U.S. patent application number 14/796599 was filed with the patent office on 2015-11-05 for solid-state imaging device and electronic apparatus.
The applicant listed for this patent is Sony Corporation. Invention is credited to Hideo Kido, Akihiro Yamada, Atsuhiko Yamamoto.
Application Number | 20150319392 14/796599 |
Document ID | / |
Family ID | 44308692 |
Filed Date | 2015-11-05 |
United States Patent
Application |
20150319392 |
Kind Code |
A1 |
Kido; Hideo ; et
al. |
November 5, 2015 |
SOLID-STATE IMAGING DEVICE AND ELECTRONIC APPARATUS
Abstract
A solid-state imaging device includes a pixel region in which
shared pixels which share pixel transistors in a plurality of
photoelectric conversion portions are two-dimensionally arranged.
The shared pixel transistors are divisionally arranged in a column
direction of the shared pixels, the pixel transistors shared
between neighboring shared pixels are arranged so as to be
horizontally reversed or/and vertically crossed, and connection
wirings connected to a floating diffusion portion, a source of a
reset transistor and a gate of an amplification transistor in the
shared pixels are arranged along the column direction.
Inventors: |
Kido; Hideo; (Kanagawa,
JP) ; Yamamoto; Atsuhiko; (Kanagawa, JP) ;
Yamada; Akihiro; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sony Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
44308692 |
Appl. No.: |
14/796599 |
Filed: |
July 10, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14242407 |
Apr 1, 2014 |
9111835 |
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14796599 |
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12929181 |
Jan 6, 2011 |
8723999 |
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14242407 |
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Current U.S.
Class: |
250/208.1 ;
257/292 |
Current CPC
Class: |
H01L 27/14643 20130101;
H01L 27/14603 20130101; H01L 27/14612 20130101; H04N 5/378
20130101; H01L 27/14625 20130101; H01L 27/14614 20130101; H01L
27/148 20130101; H04N 5/3765 20130101; H04N 5/3742 20130101; H01L
27/14636 20130101; H01L 27/1461 20130101; H01L 27/14641 20130101;
H04N 5/3745 20130101 |
International
Class: |
H04N 5/378 20060101
H04N005/378; H04N 5/3745 20060101 H04N005/3745; H04N 5/374 20060101
H04N005/374; H01L 27/146 20060101 H01L027/146; H04N 5/376 20060101
H04N005/376 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 28, 2010 |
JP |
2010-017019 |
Claims
1. An imaging device comprising: a first shared pixel including: a
first plurality of photoelectric conversion portions, and a first
transistor portion shared by the first plurality of photoelectric
conversion portions, the first transistor portion including a first
reset transistor, a first amplification transistor, and a first
selection transistor; and a second shared pixel disposed adjacent
to the first shared pixel and including: a second plurality of
photoelectric conversion portions, and a second transistor portion
shared by the second plurality of photoelectric conversion
portions, the second transistor portion including a second reset
transistor, a second amplification transistor, and a second
selection transistor, wherein a gate terminal of the first
selection transistor, a gate terminal of the first amplification
transistor, a gate terminal of the second amplification transistor,
and a gate terminal of the second selection transistor are adjacent
one another in a first row in this order, and wherein a gate
terminal of the first reset transistor and a gate terminal of the
second reset transistor are disposed in a second row.
2. The imaging device according to claim 1, wherein the first
plurality of photoelectric conversion portions includes a first
photoelectric conversion portion and a second photoelectric
conversion portion, and the second plurality of photoelectric
conversion portions includes a third photoelectric conversion
portion and a fourth photoelectric conversion portion.
3. The imaging device according to claim 2, wherein the first
photoelectric conversion portion and the third photoelectric
conversion portion are disposed in a third row, and the third row
is disposed between the first row and the second row.
4. The imaging device according to claim 2, wherein the first
shared pixel includes a first floating diffusion shared by the
first photoelectric conversion portion and the second photoelectric
conversion portion, and the second shared pixel includes a second
floating diffusion shared by the third photoelectric conversion
portion and the fourth photoelectric conversion portion.
5. The imaging device according to claim 4, wherein the first
floating diffusion is connected to the first amplification
transistor and the first reset transistor, and the second floating
diffusion is connected to the second amplification transistor and
the second reset transistor.
6. The imaging device according to claim 4, wherein the first
floating diffusion is connected to the first amplification
transistor and the first reset transistor via a first floating
diffusion line extending in a vertical direction, and the second
floating diffusion is connected to the second amplification
transistor and the second reset transistor via a second floating
diffusion line extending in the vertical direction.
7. The imaging device according to claim 1, wherein the first
selection transistor is connected to a first vertical signal line
at a first signal connection point, the second selection transistor
is connected to a second vertical signal line at a second signal
connection point, and the gate terminal of the first amplification
transistor and the gate terminal of the second amplification
transistor are disposed between the first signal connection point
and the second signal connection point in the first row.
8. The imaging device according to claim 1, wherein the first
amplification transistor is connected to a power source line at a
power connection point, and the power connection point is disposed
between the gate terminal of the first amplification transistor and
the gate terminal of the second amplification transistor in the
first row.
9. The imaging device according to claim 8, wherein the second
amplification transistor is connected to the power source line at
the power connection point.
10. The imaging device according to claim 1, further comprising: a
peripheral circuit portion including a vertical driving circuit, at
least one column signal processing circuit, a horizontal driving
circuit, an output circuit, and a control circuit.
11. The imaging device according to claim 10, wherein the control
circuit is configured to generate a clock signal or a control
signal according to a vertical synchronization signal, a horizontal
synchronization signal, and a master clock; and to provide the
clock signal or the control signal to the vertical driving circuit,
the at least one column signal processing circuit, and/or the
horizontal driving circuit.
12. The imaging device according to claim 10, wherein the vertical
driving circuit is configured to drive the first shared pixel and
the second shared pixel in row units.
13. The imaging device according to claim 10, wherein the at least
one column signal processing circuit includes a first column signal
processing circuit connected to the first shared pixel, and a
second column signal processing circuit connected to the second
shared pixel.
14. The imaging device according to claim 13, wherein the
horizontal driving circuit is configured to sequentially select the
first column signal processing circuit and the second column signal
processing circuit, and to output a respective pixel signal from
the corresponding column processing circuit to a corresponding
horizontal signal line.
15. The imaging device according to claim 10, wherein the output
circuit is configured to perform signal processing on a respective
signal supplied from the at least one column signal processing
circuit, and to output the respective processed signal.
16. The imaging device according to claim 1, further comprising: a
semiconductor substrate including a first side as a light incident
side and a second side opposite the first side, wherein the
semiconductor substrate includes the first plurality of
photoelectric conversion portions and the second plurality of
photoelectric conversion portions; and a wiring layer disposed
adjacent to the first side of the semiconductor substrate.
17. The imaging device according to claim 1, further comprising: a
semiconductor substrate including a first side as a light incident
side and a second side opposite the first side, wherein the
semiconductor substrate includes the first plurality of
photoelectric conversion portions and the second plurality of
photoelectric conversion portions; and a wiring layer disposed
adjacent to the second side of the semiconductor substrate.
18. An electronic apparatus comprising: an imaging device; an
optical system configured to guide incident light to the imaging
device; and a signal processing circuit configured to process an
output signal of the imaging device, wherein the imaging device
includes: a first shared pixel including: a first plurality of
photoelectric conversion portions, and a first transistor portion
shared by the first plurality of photoelectric conversion portions,
the first transistor portion including a first reset transistor, a
first amplification transistor, and a first selection transistor;
and a second shared pixel disposed adjacent to the first shared
pixel and including: a second plurality of photoelectric conversion
portions, and a second transistor portion shared by the second
plurality of photoelectric conversion portions, the second
transistor portion including a second reset transistor, a second
amplification transistor, and a second selection transistor,
wherein a gate terminal of the first selection transistor, a gate
terminal of the first amplification transistor, a gate terminal of
the second amplification transistor, and a gate terminal of the
second selection transistor are adjacent one another in a first row
in this order, and wherein a gate terminal of the first reset
transistor and a gate terminal of the second reset transistor are
disposed in a second row.
19. The electronic apparatus according to claim 18, wherein the
first plurality of photoelectric conversion portions includes a
first photoelectric conversion portion and a second photoelectric
conversion portion, and the second plurality of photoelectric
conversion portions includes a third photoelectric conversion
portion and a fourth photoelectric conversion portion.
20. The electronic apparatus according to claim 19, wherein the
first photoelectric conversion portion and the third photoelectric
conversion portion are disposed in a third row, and the third row
is disposed between the first row and the second row.
21. The electronic apparatus according to claim 19, wherein the
first shared pixel includes a first floating diffusion shared by
the first photoelectric conversion portion and the second
photoelectric conversion portion, and the second shared pixel
includes a second floating diffusion shared by the third
photoelectric conversion portion and the fourth photoelectric
conversion portion.
22. The electronic apparatus according to claim 21, wherein the
first floating diffusion is connected to the first amplification
transistor and the first reset transistor, and the second floating
diffusion is connected to the second amplification transistor and
the second reset transistor.
23. The electronic apparatus according to claim 21, wherein the
first floating diffusion is connected to the first amplification
transistor and the first reset transistor via a first floating
diffusion line extending in a vertical direction, and the second
floating diffusion is connected to the second amplification
transistor and the second reset transistor via a second floating
diffusion line extending in the vertical direction.
24. The electronic apparatus according to claim 18, wherein the
first selection transistor is connected to a first vertical signal
line at a first signal connection point, the second selection
transistor is connected to a second vertical signal line at a
second signal connection point, and the gate terminal of the first
amplification transistor and the gate terminal of the second
amplification transistor are disposed between the first signal
connection point and the second signal connection point in the
first row.
25. The electronic apparatus according to claim 18, wherein the
first amplification transistor is connected to a power source line
at a power connection point, and the power connection point is
disposed between the gate terminal of the first amplification
transistor and the gate terminal of the second amplification
transistor in the first row.
26. The electronic apparatus according to claim 25, wherein the
second amplification transistor is connected to the power source
line at the power connection point.
27. The electronic apparatus according to claim 18, further
comprising: a semiconductor substrate including a first side as a
light incident side and a second side opposite the first side,
wherein the semiconductor substrate includes the first plurality of
photoelectric conversion portions and the second plurality of
photoelectric conversion portions; and a wiring layer disposed
adjacent to the first side of the semiconductor substrate.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] The present invention is a Continuation of application Ser.
No. 14/242,407, filed Apr. 1, 2014, which is a Continuation of
application Ser. No. 12/929,181, filed on Jan. 6, 2011, now U.S.
Pat. No. 8,723,999, issued on May 13, 2014, and contains subject
matter related to Japanese Patent Application JP 2010-017019 filed
in the Japanese Patent Office on Jan. 28, 2010, the entire contents
of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a CMOS type solid-state
imaging device and an electronic apparatus including the
solid-state imaging device, which is applicable to, for example, a
camera or the like.
[0004] 2. Description of the Related Art
[0005] As a solid-state imaging device, a CMOS solid-state imaging
device is known. Since the CMOS solid-state imaging device has a
low power supply voltage and low power consumption, the CMOS
solid-state imaging device is used in digital still cameras,
digital video cameras, various mobile terminals such as a mobile
phone including a camera therein, printers, and the like.
[0006] In the CMOS solid-state imaging device, a pixel arranged in
a pixel region includes a plurality of pixel transistors in
addition to photodiodes PD which are photoelectric conversion
portions, unlike a CCD solid-state imaging device. In a general
unit pixel, the pixel transistor includes four transistors, namely,
a transfer transistor including a floating diffusion portion FD
which is a voltage conversion portion, a reset transistor, an
amplification transistor and a selection transistor. Alternatively,
the pixel transistor includes three transistors, namely, a transfer
transistor, a reset transistor and an amplification transistor
omitting the selection transistor. Since the photodiodes and the
plurality of pixel transistors are necessary as the unit pixel, it
is difficult to reduce the size of the pixels.
[0007] However, recently, a technology necessarily including a
so-called multi-pixel shared structure of sharing the pixel
transistors among a plurality of pixels so as to suppress the size
of an area occupied by one pixel other than the photodiode PD is
used. FIG. 29 shows an example of a solid-state imaging device in
which shared pixels are two-dimensionally arranged by the
multi-pixel shared structure described in Japanese Unexamined
Patent Application Publication No. 2006-54276. The solid-state
imaging device 91 is a four-pixel shared example in which
photodiodes PD are arranged in a zigzag. In the solid-state imaging
device 91, sets of two obliquely neighboring photodiodes PD sharing
one floating diffusion portion FD are two-dimensionally arranged.
The shared pixels include four photodiodes PD1 to PD4 arranged in a
zigzag by two sets neighboring in a vertical direction and two
circuit groups (pixel transistors) in pixel transistor forming
regions 114 divided at upper and lower positions of one set.
[0008] Transfer gate electrodes TG [TG1 to TG4] are formed between
the floating diffusion portions FD and two photodiodes PD
sandwiching the floating diffusion portions FD therebetween of two
sets. In the shared pixels, the two sets are electrically connected
to the two circuit groups in the pixel transistor regions 94
through a connection wiring 92 so as to share the four photodiodes
PD1 to PD4 in the vertical direction. That is, the floating
diffusion portions FD1 and FD2, a gate electrode (not shown) of the
amplification transistor and a source (not shown) of the reset
transistor are connected by the connection wiring 92 (so-called FD
wiring) along the vertical direction.
[0009] The related art of the CMOS solid-state imaging device are
disclosed in Japanese Unexamined Patent Application Publication
Nos. 2004-172950, 2005-157953, 2009-135319, 2003-31785, and
2005-223860.
[0010] In the Japanese Unexamined Patent Application Publication
Nos. 2004-172950 and 2005-157953, a CMOS solid-state imaging device
in which two pixels are shared is disclosed.
[0011] In the Japanese Unexamined Patent Application Publication
No. 2009-135319, a CMOS solid-state imaging device in which two
pixels located in a vertical direction and two pixels located in a
horizontal direction, namely, a total of four pixels are
shared.
[0012] In the Japanese Unexamined Patent Application Publication
No. 2003-31785, a back-illuminated type CMOS solid-state imaging
device is disclosed.
[0013] In the Japanese Unexamined Patent Application Publication
No. 2003-31785, a CMOS solid-state imaging device for performing
vertical stripe correction is disclosed.
SUMMARY OF THE INVENTION
[0014] As the configuration of the shared pixel shown in FIG. 29, a
configuration in which, among the pixel transistors divided as
shown in FIG. 30, a reset transistor Tr2 is arranged on an upper
side and a serial circuit of an amplification transistor Tr3 and a
selection transistor Tr4 is arranged on a lower side is considered.
The reset transistor Tr2 includes a reset gate electrode 106, a
source region 104 and a drain region 105. The amplification
transistor Tr3 has an amplification gate electrode 109, and
configures diffusion regions 116 and 117 as a source region and a
drain region. The selection transistor Tr4 has a selection gate
electrode 118, and configures diffusion regions 115 and 116 as a
source region and a drain region.
[0015] The reset transistor Tr2 and the serial circuit of the
amplification transistor Tr3 and the selection transistor Tr4 are
formed in the same layout in each column of the shared pixel. Tr11
to Tr14 denote transfer transistors. In the shared pixel of each
column, the two floating diffusion portions FD1 and FD2, the
amplification gate electrode 109 and the source region 104 of the
reset transistor Tr2 are electrically connected by the FD lines 92A
and 92B.
[0016] In the layout of the pixel transistors, in the amplification
transistor Tr3, the gate length is preferably as long as possible
from the viewpoint of random noise. The amplification transistor
Tr3 and the selection transistor Tr4 have to be arranged at a
constant interval d1.
[0017] The diffusion regions which become the source/drain regions
of the serial circuit of the amplification transistor Tr3 and the
selection transistor Tr4 have to be arranged at a constant interval
d2 so as to be electrically isolated from the diffusion regions of
the same serial circuit of the shared pixel of the neighboring
column.
[0018] Whenever the array of the shared pixels is increased,
symmetry between the shared photodiode PD and the serial circuit of
the amplification and selection transistors is broken. As a result,
the wiring length of the FD line 92A and 92B connecting the
floating diffusion portions FD1 and FD2 is different in each column
of the shared pixel as denoted by frames A and B of FIG. 30 and a
difference in conversion efficiency between columns occurs. In
terms of image quality, since a difference in sensitivity between
columns appears, a vertical stripe occurs.
[0019] FIGS. 31 and 32 show an example of a longitudinal four-pixel
shared type CMOS solid-state imaging device as another pixel shared
type. In the solid-state imaging device 81 shown in FIG. 31, sets
sharing two photodiodes PD neighboring in a vertical (longitudinal)
direction and a floating diffusion portion FD are two-dimensionally
arranged. The shared pixel is formed by arranging four
longitudinally arranged photodiodes PD1 to PD4 of two sets
neighboring in the vertical direction and pixel transistors
corresponding to two pixel columns of a lower side of each set.
Transfer transistors Tr11 to Tr14 are arranged in correspondence
with the photodiodes PD1 to PD4.
[0020] Each transfer gate electrode TG is commonly formed with a
transfer gate electrode of a neighboring column. In the pixel
transistors arranged on a lower side of each set having two
photodiodes PD, a serial circuit of an amplification transistor Tr3
and a selection transistor Tr4 and a reset transistor Tr2 are
formed along a row direction. That is, in the shared pixel of
neighboring columns, the serial circuit of the amplification
transistor Tr3 and the selection transistor Tr4 and the reset
transistor Tr2 are lined up and respectively arranged in the row
direction. The FD lines 92A and 92B are arranged respectively in
the shown layout. In FIG. 31, the portions corresponding to FIG. 30
are denoted by the same reference numerals and the description
thereof will be omitted.
[0021] In the solid-state imaging device 82 shown in FIG. 32, the
layout of the pixel transistors arranged on the lower side of each
set having two photodiodes PD is different from FIG. 31. That is,
only a serial circuit of an amplification transistor Tr3 and a
selection transistor Tr4 is lined up and arranged on a lower side
of one set in the same row direction and only a reset transistor
Tr2 is lined up and arranged on a lower side of the other set in
the same row direction. That is, in the shared pixel of neighboring
columns, the serial circuit of the amplification transistor Tr3 and
the selection transistor Tr4 and the reset transistor Tr2 are
respectively arranged in the row direction in the same orientation.
The FD lines 92A and 92B are respectively arranged in the shown
layout. In FIG. 32, the portions corresponding to FIG. 30 are
denoted by the same reference numerals and the description thereof
will be omitted.
[0022] As shown in FIGS. 31 and 32, in the solid-state imaging
devices 81 and 82, symmetry of the length of the FD lines 92A and
92B between columns is broken, a difference in conversion
efficiency between columns occurs, and a difference in sensitivity
between rows occurs.
[0023] If, for example, color filters of a Bayer array are used, in
any of the solid-state imaging devices 100, 81 and 82 of FIGS. 30
to 32, since a Gb pixel and a pixel Gr which become green pixels
are different in a region (area) overlapping with a gate electrode
formed of polysilicon, a difference in light absorption of the gate
electrode occurs and a sensitivity difference occurs.
[0024] It is desirable to provide a solid-state imaging device in
which a sensitivity difference hardly occurs, in a solid-state
imaging device having shared pixels.
[0025] In addition, it is desirable to provide an electronic
apparatus including the solid-state imaging device, which is
applicable to a camera or the like.
[0026] A solid-state imaging device according to an embodiment of
the present invention includes a pixel region in which shared
pixels which share pixel transistors in a plurality of
photoelectric conversion portions are two-dimensionally arranged.
The shared pixel transistors are divisionally arranged in a column
direction of the shared pixels, and the pixel transistors shared
between neighboring shared pixels are arranged so as to be
horizontally reversed or/and vertically crossed. Connection wirings
(so-called FD wirings) connected to a floating diffusion portion, a
source of a reset transistor and a gate of an amplification
transistor in the shared pixels are arranged along the column
direction.
[0027] In the solid-state imaging device of the embodiment of the
present invention, since the shared pixel transistors are
divisionally arranged in the column direction of the shared pixels
and the pixel transistors shared between the neighboring shared
pixels are arranged so as to be horizontally reversed or/and
vertically crossed, symmetry of every shared pixel including the FD
wirings is improved. For example, the wiring lengths of the FD
wirings between the neighboring shared pixels become equal,
capacitance applied to the FD wirings becomes constant in each
shared pixel, and a difference in photoelectric conversion
efficiency hardly occurs. In the case of using color filters of the
Bayer array, the area occupied by the gate electrodes included in
the Gr pixel and the Gb pixel become equal. Light absorption
amounts of the gate electrodes become equal and a difference in
sensitivity between the Gr pixel and the Gb pixel hardly
occurs.
[0028] An electronic apparatus according to another embodiment of
the present invention includes a solid-state imaging device, an
optical system configured to guide incident light to a
photoelectric conversion portion of the solid-state imaging device,
and a signal processing circuit configured to process an output
signal of the solid-state imaging device. The solid-state imaging
device includes a pixel region in which shared pixels which share
pixel transistors in a plurality of photoelectric conversion
portions are two-dimensionally arranged. The shared pixel
transistors are divisionally arranged in a column direction of the
shared pixels, and the pixel transistors shared between neighboring
shared pixels are arranged so as to be horizontally reversed or/and
vertically crossed. Connection wirings connected to a floating
diffusion portion, a source of a reset transistor and a gate of an
amplification transistor in the shared pixels are arranged along
the column direction.
[0029] In the electronic apparatus of the present invention, since
the solid-state imaging devices of the above-described embodiments
of the present invention are included, a difference in sensitivity
between the shared pixels hardly occurs.
[0030] According to the solid-state imaging device of the
embodiment of the present invention, in the solid-state imaging
device having shared pixels, it is possible to provide a
solid-state imaging device having shared pixels between which a
difference in sensitivity hardly occurs.
[0031] According to the electronic apparatus of the embodiment of
the present invention, since the solid-state imaging device having
shared pixels between which a difference in sensitivity hardly
occurs is included, it is possible to obtain high quality and to
provide an electronic apparatus with high reliability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a schematic configuration diagram of a CMOS
solid-state imaging device according to the present invention;
[0033] FIG. 2 is a configuration diagram of the main parts of a
solid-state imaging device according to a first embodiment of the
present invention;
[0034] FIG. 3 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example 1;
[0035] FIGS. 4A & 4B is a configuration diagram of the main
parts of a solid-state imaging device according to a second
embodiment of the present invention;
[0036] FIG. 5 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example 2;
[0037] FIG. 6 is a configuration diagram of the main parts of a
solid-state imaging device according to a third embodiment of the
present invention;
[0038] FIG. 7 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example 3;
[0039] FIGS. 8A & 8B is a configuration diagram of the main
parts of a solid-state imaging device according to a fourth
embodiment of the present invention;
[0040] FIG. 9 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example
4-1;
[0041] FIG. 10 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example
4-2;
[0042] FIGS. 11A & 11B is a configuration diagram of the main
parts of a solid-state imaging device according to a fifth
embodiment of the present invention;
[0043] FIG. 12 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example
5-1;
[0044] FIG. 13 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example
5-2;
[0045] FIG. 14 is a configuration diagram of the main parts of a
solid-state imaging device according to a sixth embodiment of the
present invention;
[0046] FIG. 15 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example 6;
[0047] FIG. 16 is a configuration diagram of the main parts of a
solid-state imaging device according to a seventh embodiment of the
present invention;
[0048] FIG. 17 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example 7;
[0049] FIG. 18 is a configuration diagram of the main parts of a
solid-state imaging device according to an eighth embodiment of the
present invention;
[0050] FIG. 19 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example 8;
[0051] FIG. 20 is a configuration diagram of the main parts of a
solid-state imaging device according to a ninth embodiment of the
present invention;
[0052] FIG. 21 is a configuration diagram of the main parts of a
solid-state imaging device according to Comparative Example 9;
[0053] FIG. 22 is an equivalent circuit diagram of a 4-pixel shared
structure of a 3-transistor type;
[0054] FIG. 23 is an equivalent circuit diagram of a 4-pixel shared
structure of a 4-transistor type;
[0055] FIG. 24 is an equivalent circuit diagram of a 2-pixel shared
structure of a 3-transistor type;
[0056] FIG. 25 is an equivalent circuit diagram of a 2-pixel shared
structure of a 4-transistor type;
[0057] FIG. 26 is an equivalent circuit diagram of a
2.times.2-pixel shared structure, that is, a 4-pixel shared
structure, of a 3-transistor type;
[0058] FIG. 27 is an equivalent circuit diagram of a
2.times.2-pixel shared structure, that is, a 4-pixel shared
structure, of a 4-transistor type;
[0059] FIG. 28 is a schematic configuration diagram of an
electronic apparatus according to the present invention;
[0060] FIG. 29 is a configuration diagram of the main parts of a
solid-state imaging device of a zigzag 4-pixel shared structure of
the related art;
[0061] FIG. 30 is a configuration diagram of the main parts of a
solid-state imaging device of a zigzag 4-pixel shared structure of
the related art;
[0062] FIG. 31 is a configuration diagram of the main parts of a
solid-state imaging device of a 3-transistor type of longitudinal
4-pixel shared structure of the related art; and
[0063] FIG. 32 is a configuration diagram of the main parts of a
solid-state imaging device of a 4-transistor type of longitudinal
4-pixel shared structure of the related art.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0064] Hereinafter, modes (hereinafter, referred to as embodiments)
carrying out the present invention will be described. The
description will be given in the following order.
[0065] 1. Schematic Configuration Example of CMOS Solid-state
Imaging Device
[0066] 2. Basic Configuration of Solid-state Imaging Device of
Embodiment
[0067] 3. First Embodiment (Configuration Example of Solid-state
Imaging Device)
[0068] 4. Second Embodiment (Configuration Example of Solid-state
Imaging Device)
[0069] 5. Third Embodiment (Configuration Example of Solid-state
Imaging Device)
[0070] 6. Fourth Embodiment (Configuration Example of Solid-state
Imaging Device)
[0071] 7. Fifth Embodiment (Configuration Example of Solid-state
Imaging Device)
[0072] 8. Sixth Embodiment (Configuration Example of Solid-state
Imaging Device)
[0073] 9. Seventh Embodiment (Configuration Example of Solid-state
Imaging Device)
[0074] 10. Eighth Embodiment (Configuration Example of Solid-state
Imaging Device)
[0075] 11. Ninth Embodiment (Configuration Example of Solid-state
Imaging Device)
[0076] 12. Tenth Embodiment (Configuration Example of Electronic
Apparatus)
1. Schematic Configuration Example of CMOS Solid-State Imaging
Device
[0077] FIG. 1 shows the schematic configuration of an example of a
CMOS solid-state imaging device according to each embodiment of the
present invention. The solid-state imaging device 1 of the present
example includes a pixel region (so-called imaging region) 3 in
which a plurality of pixels 2 including photoelectric conversion
portions is regularly and two-dimensionally arranged on a
semiconductor substrate 11, for example, a silicon substrate, and a
peripheral circuit portion, as shown in FIG. 1. As the pixels 2,
shared pixels in which a plurality of photoelectric conversion
portions share the other pixel transistors except a transfer
transistor are used. The plurality of pixel transistors may
include, for example, three transistors, namely a transfer
transistor, a reset transistor and an amplification transistor or
four transistors, namely, a transfer transistor, a reset
transistor, an amplification transistor and a selection
transistor.
[0078] The peripheral circuit portion includes a vertical driving
circuit 4, column signal processing circuits 5, a horizontal
driving circuit 6, an output circuit 7, a control circuit 8, and
the like.
[0079] The control circuit 8 receives data for instructing an input
clock, an operation mode, and the like and outputs data such as
internal information of the solid-state imaging device. That is,
the control circuit 8 generates a clock signal or a control signal
which is used as a reference signal of an operation of the vertical
driving circuit 4, the column signal processing circuits 5, the
horizontal driving circuit 6, or the like according to a vertical
synchronization signal, a horizontal synchronization signal and a
master clock. Such a signal is input to the vertical driving
circuit 4, the column signal processing circuits 5, the horizontal
driving circuit 6, or the like.
[0080] The vertical driving circuit 4 includes a shift register,
selects a pixel driving line, supplies a pulse signal for driving
the pixels to the selected pixel driving line, and drives the
pixels in row units. That is, the vertical driving circuit 4
sequentially selects the pixels 2 of the pixel region 3 in row
units in a vertical direction. Pixel signals based on signal
charges generated according to a light reception amount in, for
example, photodiodes which are the photoelectric conversion
elements of the pixels 2 are supplied to the column signal
processing circuits 5 through vertical signal lines 9.
[0081] The column signal processing circuits 5 are arranged in, for
example, every column of the pixel 2 so as to perform signal
processing such as noise elimination with respect to the signal
output from the pixels 2 corresponding to one row in each pixel
column. That is, the column signal processing circuits 5 perform
signal processing such as CDS, signal amplification, AD conversion,
and the like, for eliminating inherent fixed pattern noise of the
pixel 2. Horizontal selection switches (not shown) are connected
between output stages of the column signal processing circuits 5
and horizontal signal lines 10.
[0082] The horizontal driving circuit 6 includes, for example, a
shift register, sequentially outputs a horizontal scanning pulse so
as to sequentially select the column signal processing circuits 5,
and outputs the pixel signals from the column signal processing
circuits 5 to horizontal signal lines 10.
[0083] The output circuit 7 performs signal processing with respect
to the signals sequentially supplied from the column signal
processing circuits 5 through the horizontal signal lines 10 and
outputs the processed signals. For example, only buffering may be
performed, black level adjustment, column deviation correction, a
variety of digital signal processing, and the like may be
performed. An input/output terminal 12 exchanges a signal with an
external device.
[0084] In a front-illuminated type CMOS solid-state imaging device,
a plurality of shared pixels which shares the pixel transistors in
photodiodes PD, which are a plurality of photoelectric conversion
portions, is formed in a first conductive type semiconductor well
region, for example, p-type semiconductor well region corresponding
to the pixel region of the semiconductor substrate. Each shared
pixel is partitioned in an element isolation region. A multi-layer
wiring layer having a plurality of wiring layers with an interlayer
insulating films interposed therebetween is formed on a front
surface side of the semiconductor substrate except on the
photodiodes PD, and color filters and an on-chip lens are laminated
and formed on the multi-layer wiring layer with a planarization
film interposed therebetween. Light is irradiated to the
photodiodes PD rather than the front surface side of the
semiconductor substrate through the on-chip lens.
[0085] In a back-illuminated type CMOS solid-state imaging device,
a plurality of shared pixels which shares the pixel transistors in
photodiodes PD, which are a plurality of photoelectric conversion
portions, is formed in a thinned semiconductor substrate, that is,
a semiconductor substrate in which a first conductive type
semiconductor well region, that is, a p-type semiconductor well
region is formed. Each shared pixel is partitioned in an element
isolation region. A multi-layer wiring layer having a plurality of
wiring layers with an interlayer insulating film interposed
therebetween is formed on one surface side of the semiconductor
substrate, and a support substrate formed of a semiconductor
substrate is adhered thereon. The wiring arrangement is not limited
and the wiring is formed even on photodiodes PD. Color filters and
the on-chip lens are laminated and formed on a rear surface side of
the semiconductor substrate. Light is irradiated to the photodiodes
PD rather than the rear surface side of the semiconductor substrate
through the on-chip lens.
2. Basic Configuration of Solid-State Imaging Device of
Embodiment
[0086] The solid-state imaging device according to the present
embodiment, that is, the CMOS solid-state imaging device includes
shared pixels sharing pixel transistors in a plurality of
photoelectric conversion portions. The shared pixels are regularly
and two-dimensionally arranged so as to form a pixel region. The
pixel transistors are configured as a 3-transistor type including a
transfer transistor, a reset transistor and an amplification
transistor or a 4-transistor type further including a selection
transistor in addition to the 3-transistor type. Among the pixel
transistors of the shared pixels, the transfer transistor includes
transfer transistors equal in number to the number of photoelectric
conversion portions and each of the other shared pixel transistors.
The shared pixel transistor, that is, the pixel transistors other
than the transfer transistors are divided and arranged in a column
direction of the shared pixels.
[0087] In the present embodiment, between neighboring shared
pixels, for example, between shared pixels of neighboring columns
or neighboring rows, the shared pixel transistors are horizontally
reversed, are vertically crossed or are horizontally reversed and
vertically crossed. A connection wiring, that is, an FD wiring,
connected to a floating diffusion portion FD of each shared pixel,
a source of a reset transistor and a gate of an amplification
transistor is arranged along a column direction. A row direction
denotes a direction along a row and a column direction denotes a
direction along a column.
[0088] According to the solid-state imaging device according to the
present embodiment, between neighboring shared pixels in which the
pixel transistors shared within the shared pixels are divided and
arranged in the column direction, the shared pixel transistors are
arranged so as to be horizontally reversed and vertically crossed.
By this configuration, symmetry of every shared pixel including the
FD wiring of the shared pixel is improved, a difference in wiring
length of the FD wiring disappears, and the wiring capacitance of
the FD wiring becomes constant in every shared pixel. Accordingly,
a difference in photoelectric conversion efficiency of every column
or row hardly occurs and a difference in sensitivity between
columns or rows disappears. As a result, in terms of image quality,
a vertical stripe that is not a light amount of the photoelectric
conversion portion until it is filled with charge, but that is a
so-called sensitivity light amount, disappears.
[0089] In the case of using a color filter of the Bayer array,
between neighboring shared pixels, by arranging the shared pixel
transistors to be vertically crossed or to be horizontally reversed
and to be vertically crossed, the occupied area of the base
electrode overlapping a Gr pixel and a Gb pixel becomes equal. That
is, the degree of light absorption by a gate electrode formed of a
polysilicon becomes equal and a difference in sensitivity between
the Gr pixel and the Gb pixel hardly occurs. Accordingly, it is
possible to provide a solid-state imaging device with a plurality
of shared pixels, in which a difference in sensitivity hardly
occurs.
3. First Embodiment
Configuration Example of Solid-State Imaging Device
[0090] FIG. 2 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to a first embodiment of the
present invention. FIG. 2 shows the schematic configuration of main
portions applied to the CMOS solid-state imaging device in which
pixel transistors of the 3-transistor type are provided and a
plurality of shared pixels having a zigzag 4-pixel shared structure
is arranged. The present embodiment is characterized in the
arrangement of the pixel transistors and will be described in
comparison with a Comparative Example 1 of FIG. 3.
[0091] FIG. 22 shows an equivalent circuit of the shared pixels
having the 4-pixel shared structure of the 3-transistor type. The
shared pixels according to the present example include four
photodiodes PD [PD1 to PD4] which are the photoelectric conversion
portions, four transfer transistors Tr1 [Tr1 to Tr14], one reset
transistor Tr2, and one amplification transistor Tr3. In the shared
pixels, a first floating diffusion portion FD1 is shared between
the two photodiodes PD1 and PD2 and a second floating diffusion
portion FD2 is shared between two photodiodes PD3 and PD4.
[0092] The photodiodes PD1 to PD4 are connected to the transfer
transistors Tr11 to Tr14, respectively. That is, two photodiodes
PD1 and PD2 are connected to the first floating diffusion portion
FD1 through the transfer transistors Tr11 and Tr12. Two photodiodes
PD3 and PD4 are connected to the second floating diffusion portion
FD2 through the transfer transistor Tr13 and Tr14. The first
floating diffusion portion FD1 and the second floating diffusion
portion FD2 are connected and the connection point is connected to
a source of the reset transistor Tr2 and a gate of the
amplification transistor Tr3. A drain of the reset transistor Tr2
is connected to a power source Vdd. A drain of the amplification
transistor Tr3 is connected to the power source Vdd and a source
thereof is connected to a vertical signal line 9.
[0093] First, a solid-state imaging device according to Comparative
Example 1 of FIG. 3 will be described. In the solid-state imaging
device 101 of Comparative Example 1, sets sharing one floating
diffusion portion FD between two obliquely neighboring photodiodes
PD are two-dimensionally arranged, and 4-pixel shared pixels 102 of
the zigzag array are configured by two sets neighboring in a
vertical (longitudinal) direction. That is, a first set sharing the
first floating diffusion portion FD1 between two obliquely
neighboring photodiodes PD1 and PD2 and a second set sharing the
second floating diffusion portion FD2 between two obliquely
neighboring photodiodes PD3 and PD4 are included. The first set and
the second set are adjacently arranged in a longitudinal
direction.
[0094] The transfer gate electrodes TG1 and TG2 are respectively
formed between the photodiodes PD1 and PD2 and the first floating
diffusion portion FD1 so as to form the first transfer transistor
Tr11 and the second transfer transistor Tr12. The transfer gate
electrodes TG3 and TG4 are respectively formed between the
photodiodes PD3 and PD4 and the second floating diffusion portion
FD2 so as to form the third transfer transistor Tr13 and the fourth
transfer transistor Tr14.
[0095] In the shared pixels 102, the reset transistor Tr2 and the
amplification transistor Tr3 are arranged to be divided vertically.
That is, the reset transistor Tr2 including a source region 104, a
drain region 105 and a reset gate electrode 106 is arranged on an
upper side of a first set having the two photodiodes PD1 and PD2.
In addition, an amplification transistor Tr3 including a source
region 107, a drain region 108 and an amplification gate electrode
109 is arranged on an upper side of a second set having the two
photodiodes PD3 and PD4. The reset transistor Tr2 and the
amplification transistor Tr3 are arranged so as to be deviated from
each other in a row (lateral) direction of the shared pixel
102.
[0096] Between the shared pixels neighboring in the row direction,
that is, between the shared pixels 102 of the neighboring columns,
the mutual amplification transistors Tr3 are lined up in the same
direction and are arranged in the same row direction and the mutual
reset transistors Tr2 are lined up in the same direction and
arranged in the same row direction. In the shared pixel 102 of one
of the neighboring columns, the source region 104 of the reset
transistor, the amplification gate electrode 109 of the
amplification transistor, the first floating diffusion portion FD1
and the second floating diffusion portion FD2 are connected by an
FD wiring 111A. In the shared pixel 102 of the other of the
neighboring columns, the source region 104 of the reset transistor,
the amplification gate electrode 109 of the amplification
transistor, the first floating diffusion portion FD1 and the second
floating diffusion portion FD2 are connected by an FD wiring 111B.
In the solid-state imaging device 101 of Comparative Example 1, the
zigzag 4-pixel shared pixels 102 of the 3-transistor type are
configured by the four photodiodes PD1 to PD4 of the zigzag array
denoted by a broken line 112 and the pixel transistors Tr11 to
Tr14, Tr2 and Tr3.
[0097] In the solid-state imaging device 101 according to
Comparative Example 1, since the lengths of the FD wirings 111A and
111B of the shared pixels 102 of the neighboring columns are
identical, there is no difference in conversion efficiency
associated with the FD wiring length. However, in the configuration
having the color filter of the Bayer array, as shown in FIG. 3, the
Gb pixel includes the reset gate electrode 106 formed of
polysilicon of the reset transistor Tr2 in the shared pixels (that
is, unit cells) 102. The Gr pixel includes the amplification gate
electrode 109 formed of polysilicon of the amplification transistor
Tr3 in the shared pixels (unit cells) 102. The gate length of the
amplification gate electrode 109 is greater than that of the reset
gate electrode 106. The Gr pixel and the Gb pixel are the same
green pixel, but include gate electrodes having different areas.
Thus, a difference in light absorption between the Gr pixel and the
Gb pixel occur due to the gate electrodes. As a result, a deviation
in sensitivity between columns occurs and thus a vertical stripe
occurs.
[0098] Next, the solid-state imaging device according to the first
embodiment will be described. In the solid-state imaging device 21
of the first embodiment, as shown in FIG. 2, sets sharing one
floating diffusion portion FD between two obliquely neighboring
photodiodes PD are two-dimensionally arranged, and 4-pixel shared
pixels 22 of the zigzag array are configured by two sets
neighboring in a vertical direction. That is, a first set sharing
the first floating diffusion portion FD1 between two obliquely
neighboring photodiodes PD1 and PD2 and a second set sharing the
second floating diffusion portion FD2 between two obliquely
neighboring photodiodes PD3 and PD4 are adjacently arranged in a
longitudinal direction.
[0099] The transfer gate electrodes TG1 and TG2 are respectively
formed between the photodiodes PD1 and PD2 and the first floating
diffusion portion FD1 so as to form the first transfer transistor
Tr11 and the second transfer transistor Tr12. The transfer gate
electrodes TG3 and TG4 are respectively formed between the
photodiodes PD3 and PD4 and the second floating diffusion portion
FD2 so as to form the third transfer transistor Tr13 and the fourth
transfer transistor Tr14.
[0100] In the present embodiment, in the shared pixels 22, the
reset transistor Tr2 and the amplification transistor Tr3 are
arranged to be divided vertically. At this time, the mutual
amplification transistors Tr3 are arranged between the shared
pixels neighboring in the row direction, that is, the shared pixels
102 of the neighboring columns, so as to be vertically crossed and
the mutual reset transistors Tr2 are arranged so as to be
vertically crossed (see arrow). That is, the reset transistor Tr2
and the amplification transistor Tr3 are lined up on the upper side
of the first set having the two photodiodes PD1 and PD2 of one
column and the upper side of the first set having the two
photodiodes PD1 and PD2 of the other column. The amplification
transistor Tr3 and the reset transistor Tr2 are lined up on the
upper side of the second set having the two photodiodes PD3 and PD4
of one column and the other column such that the arrays of the
reset transistor Tr2 and the amplification transistor Tr3 are
vertically crossed. The reset transistor Tr2 and the amplification
transistor Tr3 arranged vertically are arranged substantially at
the same positions without being deviated in the row direction.
[0101] The reset transistor Tr2 has a source region 24, a drain
region 25 and a reset gate electrode 26. The amplification
transistor Tr3 has a source region 27, a drain region 28 and an
amplification gate electrode 29.
[0102] In the shared pixels 22 of one of the neighboring columns,
the source region 24 of the reset transistor, the amplification
gate electrode 29 of the amplification transistor, and the first
and second floating diffusion portions FD1 and FD2 are electrically
connected by an FD wiring 31A. In the shared pixels 22 of the other
of the neighboring columns, the source region 24 of the reset
transistor, the amplification gate electrode 29 of the
amplification transistor and the first and second floating
diffusion portions FD1 and FD2 are electrically connected by an FD
wiring 31B. In the present embodiment, the zigzag 4-pixel shared
pixels 22 of the 3-transistor type are configured by the four
photodiodes PD1 to PD4 of the zigzag array denoted by a broken line
32 and the pixel transistors Tr11 to Tr14, Tr2 and Tr3.
[0103] According to the solid-state imaging device 21 according to
the first embodiment, the divisionally arranged reset transistor
Tr2 and amplification transistors Tr3 are arranged so as to be
vertically crossed between the shared pixels 22 of the neighboring
columns. By this configuration, symmetry of every shared pixel
including the FD wiring 31 of the shared pixel 22 is improved, a
difference in wiring length of the FD wiring 31A and 31B
disappears, and the wiring capacitance of the FD wirings 31A and
31B becomes constant in every shared pixel. Accordingly, a
difference in photoelectric conversion efficiency of each column
hardly occurs and a difference in sensitivity between columns
disappears. As a result, a vertical stripe disappears.
[0104] In the case of using the color filter of the Bayer array,
between the shared pixels of the neighboring columns, by arranging
the reset transistor Tr2 and the amplification transistor Tr3 to be
vertically crossed, the respective reset gate electrodes 26 are
included in the Gr pixel and the Gb pixel. Since the reset gate
electrodes 26 formed of polysilicon and having the same area are
included in the Gr pixel and the Gb pixel, a difference in light
absorption does not occur due to the reset gate electrodes. As a
result, the vertical stripe does not occur. Accordingly, it is
possible to provide a solid-state imaging device with a plurality
of shared pixels, in which a difference in sensitivity between the
shared pixels hardly occurs.
4. Second Embodiment
Configuration Example of Solid-State Imaging Device
[0105] FIG. 4 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to a second embodiment of the
present invention. FIG. 4 shows the schematic configuration of main
portions applied to the CMOS solid-state imaging device in which
pixel transistors of the 4-transistor type are provided and a
plurality of shared pixels having a zigzag 4-pixel shared structure
is arranged. The arrangement of the pixel transistors and the like
of the present embodiment will be described in comparison with
Comparative Example 2 of FIG. 5.
[0106] FIG. 23 shows an equivalent circuit of the shared pixels
having the 4-pixel shared structure of the 4-transistor type. The
shared pixels according to the present example include four
photodiodes PD [PD1 to PD4] which are the photoelectric conversion
portions, four transfer transistors Tr1 [Tr11 to Tr14], one reset
transistor Tr2, one amplification transistor Tr3, and one selection
transistor Tr4. A drain of the selection transistor Tr4 is
connected to a source of the amplification transistor Tr3 and a
source thereof is connected to a vertical signal line 9. Since the
other configuration has the same connection circuit as that
described in FIG. 22, the portions corresponding to FIG. 22 are
denoted by the same reference numerals and the description thereof
will be omitted.
[0107] First, a solid-state imaging device according to Comparative
Example 2 of FIG. 5 will be described. The solid-state imaging
device 114 of Comparative Example 2 is a CMOS solid-state imaging
device having a zigzag 4-pixel shared structure. The solid-state
imaging device 114 of Comparative Example 2 is the same as
Comparative Example 1 except that the pixel transistors of the
4-transistor type including the transfer transistor Tr1 [Tr11 to
Tr14], the reset transistor Tr2, the amplification transistor Tr3
and the selection transistor Tr4 are used. In the solid-state
imaging device 114 of the present comparative example, the reset
transistor Tr2 is arranged on the upper side of the first set
having the two photodiodes PD1 and PD2 and a serial circuit of the
amplification transistor Tr3 and the selection transistor Tr4 is
arranged on the upper side of the second set having the two
photodiodes PD3 and PD4. This serial circuit includes diffusion
regions 115, 116 and 117 which become the source/drain regions, the
amplification gate electrode 109, and the selection gate electrode
118. That is, the amplification transistor Tr3 is formed by the
diffusion regions 116 and 117 as the source region and the drain
region and the amplification gate electrode 109. The selection
transistor Tr4 is formed by the diffusion regions 115 and 116 as
the source region and the drain region and the selection gate
electrode 118. In the shared pixels 122 of the neighboring columns,
the reset transistors Tr2 are lined up in the same direction and
are arranged in the same row direction and the serial circuits of
the amplification transistors Tr3 and the selection transistors Tr4
are lined up in the same direction and are arranged in the same row
direction.
[0108] Since the other configuration is the same as that described
in FIG. 3, the portions corresponding to FIG. 3 are denoted by the
same reference numerals and the description thereof will be
omitted.
[0109] In the solid-state imaging device 114 according to
Comparative Example 2, the wiring lengths of the FD wiring 111A of
the shared pixel 122 of the left column and the FD wiring 111B of
the shared pixel 122 of the right column are different in FIG. 5.
That is, the FD wiring 111B of the right column is greater than the
FD wiring 111A of the left column by the length denoted by an
elliptic frame C. Accordingly, a difference in wiring capacitance
between the FD wiring 111A and the FD wiring 111B occurs and thus
conversion efficiency is different between the shared pixels of the
neighboring columns. As a result, a difference in conversion
efficiency between columns occurs and thus a vertical stripe
occurs.
[0110] Next, the solid-state imaging device according to the second
embodiment will be described. The solid-state imaging device 34 of
the second embodiment is a CMOS solid-state imaging device having
the zigzag 4-pixel shared structure. The solid state imaging device
34 of the second embodiment includes the pixel transistors of the
4-transistor type including the transfer transistors Tr1 [TR11 to
Tr14], the reset transistor Tr2, the amplification transistor Tr3
and the selection transistor Tr4.
[0111] In the solid-state imaging device 34 according to the second
embodiment, as shown in FIG. 4, in each of the shared pixels of the
neighboring columns, the reset transistor Tr2 is arranged on the
upper side of the first set having the two photodiodes PD1 and PD2.
In the shared pixels of the neighboring columns, the serial
circuits of the amplification transistor Tr3 and the selection
transistor Tr4 are integrally arranged on the upper side of the
second set having the two photodiodes PD3 and PD4 so as to be
horizontally reversed between the neighboring columns. That is, as
shown in FIG. 4B, the drain regions of the amplification
transistors Tr3 of the second serial circuits are formed of the
common diffusion region 37 and the serial circuits are arranged so
as to be horizontally reversed between the shared pixels of the
neighboring columns. The serial circuit includes the amplification
transistor Tr3 including the diffusion regions 36 and 37 as the
source region and the drain region and the amplification gate
electrode 29 and the selection transistor Tr4 including the
diffusion regions 35 and 36 as the source region and the drain
region and the selection gate electrode 38.
[0112] Since the other configuration has the same connection
circuit as that described in the first embodiment, the portions
corresponding to FIG. 2 are denoted by the same reference numerals
and the description thereof will be omitted.
[0113] According to the solid-state imaging device 34 of the second
embodiment, between the shared pixels 42 of the neighboring
columns, the wiring lengths of the FD wiring 31A and the FD wiring
31B become equal. Accordingly, a difference in wiring capacitance
between the FD wiring 31A and the FD wiring 31B does not occur and
a difference in conversion efficiency between columns does not
occur. As a result, a difference in sensitivity between columns
does not occur and a vertical stripe does not occur. Accordingly,
it is possible to provide a solid-state imaging device with a
plurality of shared pixels, in which a difference in sensitivity
between the shared pixels hardly occurs.
5. Third Embodiment
Configuration Example of Solid-State Imaging Device
[0114] FIG. 6 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to a third embodiment of the
present invention. FIG. 6 shows the schematic configuration of main
portions applied to the CMOS solid-state imaging device in which
pixel transistors of the 4-transistor type are provided and a
plurality of shared pixels having a zigzag 4-pixel shared structure
is arranged. The arrangement of the pixel transistors and the like
of the present embodiment will be described in comparison with a
Comparative Example 3 of FIG. 7.
[0115] First, the solid-state imaging device according to
Comparative Example 3 of FIG. 7 will be described. The solid-state
imaging device 124 of Comparative Example 3 is a CMOS solid-state
imaging device having a zigzag 4-pixel shared structure using color
filters of the Bayer array. Since the other configuration is the
same as that of the above-described Comparative Example 2 except
that the Gr pixel and Gb pixel are included, the portions
corresponding to FIG. 5 are denoted by the same reference numerals
and the description thereof will be omitted.
[0116] In the solid-state imaging device 124 of Comparative Example
3, similar to that described in FIG. 5, the wiring lengths of the
FD wiring 111A of the shared pixel 122 of the left column and the
FD wiring 111B of the shared pixel 122 of the right column are
different. That is, the FD wiring 111B of the right column is
greater than the FD wiring 111A of the left column by the length
denoted by an elliptic frame C. Accordingly, a difference in wiring
capacitance between the FD wiring 111A and the FD wiring 111B
occurs and thus conversion efficiency is different between the
shared pixels of the neighboring columns. As a result, a difference
in conversion efficiency between columns occurs and thus a vertical
stripe occurs.
[0117] In addition, the Gb pixel has a reset gate electrode 106
formed of polysilicon of the reset transistor Tr2 in the shared
pixels 122. The Gr pixel has an amplification gate electrode 109
formed of polysilicon of the amplification transistor Tr3 in the
shared pixels 122. The gate length of the amplification gate
electrode 109 is greater than that of the reset gate electrode 106.
The Gr pixel and the Gb pixel are the same green pixel, but include
gate electrodes having different areas. Thus, a difference in light
absorption between the Gr pixel and the Gb pixel occurs due to the
gate electrodes. As a result, a deviation in sensitivity between
columns occurs and thus a vertical stripe occurs.
[0118] Next, the solid-state imaging device according to the third
embodiment will be described. The solid-state imaging device 44
according to the third embodiment is a CMOS solid-state imaging
device having a zigzag 4-pixel shared structure. The solid-state
imaging device 44 of the third embodiment is the same as that of
the second embodiment except that the arrangement of the pixel
transistors is changed.
[0119] In the solid-state imaging device 44 according to the third
embodiment, the serial circuits of the amplification transistor Tr3
and the selection transistor Tr4 are arranged between the shared
pixels 45 of the neighboring columns so as to be vertically crossed
without being horizontally reversed and, similarly, the reset
transistors Tr2 are arranged so as to be vertically crossed (see
arrow). That is, the reset transistor Tr2 and the serial circuit
are lined up on the upper side of the first set having the two
photodiodes PD1 and PD2 of one column and the upper side of the
first set having the two photodiodes PD1 and PD2 of the other
column. The serial circuit and the reset transistor Tr2 are lined
up on the upper side of the second set having the two photodiodes
PD3 and PD4 of one column and the other column such that the arrays
of the reset transistor Tr2 and the serial circuit are vertically
crossed.
[0120] Since the other configuration is the same as that of the
second embodiment, the portions corresponding to FIG. 4 are denoted
by the same reference numerals and the description thereof will be
omitted.
[0121] According to the solid-state imaging device 44 according to
the third embodiment, the reset transistors Tr2 and the serial
circuits of the amplification transistor Tr3 and the selection
transistor Tr4 are arranged so as to be vertically crossed between
the shared pixels 45 of the neighboring columns. By this
configuration, the wiring lengths of the FD wiring 31A and the FD
wiring 31B between the shared pixels 45 of the neighboring columns
become equal, a difference in wiring capacitance between the FD
wiring 31A and the FD wiring 31B does not occur, and a difference
in conversion efficiency between columns does not occur. As a
result, a difference in sensitivity between columns disappears and
a vertical stripe does not occur.
[0122] In the case of using the color filters of the Bayer array,
portions of the reset gate electrode 26 and the amplification gate
electrode 29 are respectively included in the Gr pixel and the Gb
pixel according to the above-described configuration. Since the
portions of the reset gate electrode 26 and the amplification gate
electrode 29 formed of polysilicon and having the same area are
included in the Gr pixel and the Gb pixel, a difference in light
absorption does not occur due to the reset gate electrodes. As a
result, a vertical stripe does not occur. Accordingly, it is
possible to provide a solid-state imaging device having a 4-pixel
shared structure, in which a difference in sensitivity between the
shared pixels hardly occurs.
6. Fourth Embodiment
Configuration Example of Solid-State Imaging Device
[0123] FIG. 8 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to a fourth embodiment of the
present invention. FIG. 8 shows the schematic configuration of main
portions applied to the CMOS solid-state imaging device in which
pixel transistors of the 3-transistor type are provided and a
plurality of shared pixels having a longitudinal 4-pixel shared
structure is arranged. The arrangement of the pixel transistors and
the like of the present embodiment will be described in comparison
with Comparative Examples 4-1 and 4-2 of FIGS. 9 and 10.
[0124] First, Comparative Example 4-1 of FIG. 9 will be described.
The solid-state imaging device 126 of Comparative Example 4-1
includes shared pixels having a longitudinal 4-pixel shared
structure and including four photodiodes PD [PD1 to PD4] arranged
in the vertical (longitudinal) direction. That is, a first set
sharing a first floating diffusion portion FD1 between two
longitudinally neighboring photodiodes PD1 and PD2 and a second set
sharing a second floating diffusion portion FD2 between two
longitudinally neighboring photodiodes PD3 and PD4 are included.
The first set and the second set are adjacently arranged in the
vertical direction.
[0125] The transfer gate electrodes TG1 and TG2 are respectively
formed between the photodiodes PD1 and PD2 and the first floating
diffusion portion FD1 so as to form the first transfer transistor
Tr11 and the second transfer transistor Tr12. The transfer gate
electrodes TG3 and TG4 are respectively formed between the
photodiodes PD3 and PD4 and the second floating diffusion portion
FD2 so as to form the third transfer transistor Tr13 and the fourth
transfer transistor Tr14. The transfer gate electrodes TG1 to TG4
are formed commonly with the transfer gate electrodes TG1 to TG4 of
the shared pixels of the neighboring column.
[0126] The amplification transistor Tr3 and the reset transistor
Tr2 are lined up and arranged in the row direction on the lower
side of the first set over the shared pixels 127 of the neighboring
column and, similarly, the amplification transistor Tr3 and the
reset transistor Tr2 are lined up and arranged in the row direction
on the lower side of the second set. As shown, the FD wirings 111A
and 111B are formed. Since the other configuration is the same as
that of the above-described comparative example, the portions
corresponding thereto are denoted by the same reference numerals
and the description thereof will be omitted.
[0127] In the solid-state imaging device 128 of Comparative Example
4-2 of FIG. 10, the reset transistors Tr2 corresponding to the
shared pixels of the columns are lined up and arranged in the row
direction on the lower side of the first set over the shared pixels
127 of the neighboring columns. In addition, the amplification
transistors Tr3 corresponding to the shared pixels of the columns
are lined up and arranged in the row direction on the lower side of
the second set over the shared pixels 127 of the neighboring
columns. As shown, the FD wirings 111A and 111B are formed. Since
the other configuration is the same as that of FIG. 9, the portions
corresponding thereto are denoted by the same reference numerals
and the description thereof will be omitted.
[0128] In the solid-state imaging device 126 according to
Comparative Example 4-1 and the solid-state imaging device 128 of
Comparative Example 4-2, the wiring lengths of the FD wiring 111A
of the left shared pixel and the FD wiring 111B of the right shared
pixel are different. The wiring lengths are different due to the
presence of the wiring portions denoted by elliptic frames E to G
or an elliptic frame H. Accordingly, a difference in wiring
capacitance occurs, a difference in conversion efficiency between
columns occurs, and a vertical stripe occurs. In the case of using
the color filters of the Bayer array, since the areas of the gate
electrodes included in the Gr pixel and the Gb pixel are different,
a difference in light absorption of the gate electrodes of the Gr
pixel and the Gb pixel occurs. As a result, a deviation in
sensitivity between columns occurs and thus a vertical stripe
occurs.
[0129] Next, the solid-state imaging device according to the fourth
embodiment will be described. The solid-state imaging device 47 of
the fourth embodiment includes shared pixels having a longitudinal
4-pixel shared structure and including four photodiodes PD [PD1 to
PD4] arranged in the vertical (longitudinal) direction, as shown in
FIG. 8. That is, a first set sharing a first floating diffusion
portion FD1 between two longitudinally neighboring photodiodes PD1
and PD2 and a second set sharing a second floating diffusion
portion FD2 between two longitudinally neighboring photodiodes PD3
and PD4 are included. The first set and the second set are
adjacently arranged in the vertical direction.
[0130] The transfer gate electrodes TG1 and TG2 are respectively
formed between the photodiodes PD1 and PD2 and the first floating
diffusion portion FD1 so as to form the first transfer transistor
Tr11 and the second transfer transistor Tr12. The transfer gate
electrodes TG3 and TG4 are respectively formed between the
photodiodes PD3 and PD4 and the second floating diffusion portion
FD2 so as to form the third transfer transistor Tr13 and the fourth
transfer transistor Tr14. The transfer gate electrodes TG1 to TG4
are formed commonly with the transfer gate electrodes TG1 to TG4 of
the shared pixels of the neighboring column.
[0131] In the present embodiment, the amplification transistors Tr3
of the shared pixels of the neighboring columns are horizontally
reversed and the respective drain regions 28 are commonly
integrated. The reset transistors Tr2 of the shared pixels of the
neighboring columns are horizontally reversed and the respective
drain regions 25 are commonly integrated. The horizontally reversed
and integrated amplification transistors Tr3 and the horizontally
reversed and integrated reset transistors Tr2 are arranged in the
row direction. Simultaneously, the array of the integrated
amplification transistors Tr3 and the integrated reset transistors
Tr2 is arranged so as to be vertically crossed between the lower
side of the first set and the lower side of the second set.
[0132] In the left shared pixel 48, the first floating diffusion
portion FD1 and the amplification gate electrode 29 of the upper
stage and the second floating diffusion portion FD2 and the source
region 24 of the reset transistor Tr2 of the lower stage are
electrically connected by an FD wiring 31A. In the right shared
pixel 48, the first floating diffusion portion FD1 and the source
region 24 of the reset transistor Tr2 of the upper stage and the
second floating diffusion portion FD2 and the amplification gate
electrode 29 of the lower stage are electrically connected by an FD
wiring 31B. Since the other configuration is the same as that of
the above-described embodiment, the portions corresponding thereto
are denoted by the same reference numerals and the description
thereof will be omitted.
[0133] According to the solid-state imaging device 47 according to
the fourth embodiment, by arranging the pixel transistors as
described above, the wiring length of the FD wiring 31A of the
shared pixel 48 of the left column and the FD wiring 31B of the
shared pixel 48 of the right column become equal. Accordingly, a
difference in wiring capacitance between the FD wirings 31A and 31B
does not occur and a difference in conversion efficiency between
columns does not occur. As a result, a vertical stripe does not
occur.
[0134] In the case of using the color filters of the Bayer array,
by arranging the pixel transistors as described above, the gate
electrodes having the same area are included in the Gr pixel and
the Gb pixel. Accordingly, a difference in light absorption of the
gate electrodes formed of polysilicon between the Gr pixel and the
Gb pixel does not occur and a vertical stripe does not occur.
Accordingly, it is possible to provide a solid-state imaging device
having a longitudinal 4-pixel shared structure, in which a
difference in sensitivity between the shared pixels hardly
occurs.
7. Fifth Embodiment
Configuration Example of Solid-State Imaging Device
[0135] FIG. 11 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to a fifth embodiment of the
present invention. FIG. 11 shows the schematic configuration of
main portions applied to the CMOS solid-state imaging device in
which pixel transistors of the 4-transistor type are provided and a
plurality of shared pixels having a longitudinal 4-pixel shared
structure is arranged. The arrangement of the pixel transistors and
the like of the present embodiment will be described in comparison
with Comparative Examples 5-1 and 5-2 of FIGS. 12 and 13.
[0136] First, the solid-state imaging device according to
Comparative Example 5-1 of FIG. 12 will be described. In the
solid-state imaging device 131 of Comparative Example 5-1, instead
of the above-described array of the reset transistor and the
amplification transistor of FIG. 9, the serial circuit of the
amplification transistor Tr3 and the selection transistor Tr4 and
the reset transistor Tr2 are arranged. The configuration of the
serial circuit is the same as that described in FIG. 5. A reference
numeral 133 denotes the shared pixel. Since the other configuration
is the same as that of FIG. 9, the portions corresponding thereto
are denoted by the same reference numerals and the description
thereof will be omitted.
[0137] In the solid-state imaging device 132 of Comparative Example
5-2 of FIG. 13, instead of the array of the reset transistors and
the amplification transistors of FIG. 10, the reset transistors Tr2
and the serial circuits of the amplification transistor Tr3 and the
selection transistor Tr4 are arranged. The configuration of the
serial circuit is the same as that described in FIG. 5. A reference
numeral 134 denotes the shared pixel. Since the other configuration
is the same as that of FIG. 10, the portions corresponding thereto
are denoted by the same reference numerals and the description
thereof will be omitted.
[0138] In the solid-state imaging device 131 according to
Comparative Example 5-1 and the solid-state imaging device 132 of
Comparative Example 5-2, the wiring lengths of the FD wiring 111A
of the left shared pixel and the FD wiring 111B of the right shared
pixel are different. The wiring lengths are different due to the
presence of the wiring portions denoted by elliptic frames E to G
or an elliptic frame H. Accordingly, a difference in wiring
capacitance occurs, a difference in conversion efficiency between
columns occurs, and a vertical stripe occurs. In the case of using
the color filters of the Bayer array, since the areas of the gate
electrodes included in the Gr pixel and the Gb pixel are different,
a difference in light absorption of the gate electrodes of the Gr
pixel and the Gb pixel occurs. As a result, a deviation in
sensitivity between columns occurs and thus a vertical stripe
occurs.
[0139] Next, the solid-state imaging device according to the fifth
embodiment will be described. In the solid-state imaging device 49
of the fifth embodiment, as shown in FIG. 11, the serial circuit of
the amplification transistor Tr3 and the selection transistor Tr4
and the reset transistor Tr2 are horizontally reversed in the
shared pixels of the neighboring columns. The horizontally reversed
serial circuit and reset transistor Tr2 are arranged so as to be
vertically crossed. That is, two reset transistors Tr2 in which the
drain region 25 is commonly integrated and two serial circuits in
which the drain region of the amplification transistor Tr3 is
commonly integrated are arranged in the row direction on the lower
side of the first set having two photodiodes PD1 and PD2. The
integrated reset transistor Tr2 and the serial circuit are arranged
on the lower side of the second set having two photodiodes PD3 and
PD4 so as to become the array crossing the array of the integrated
serial circuit and reset transistor Tr2. The configuration of the
serial circuit is the same as that described in FIG. 4. A reference
numeral 51 denotes the shared pixel.
[0140] Since the other configuration is the same as that of FIG. 8,
the portions corresponding to FIG. 8 are denoted by the same
reference numerals and the description thereof will be omitted.
[0141] According to the solid-state imaging device 49 according to
the fifth embodiment, by arranging the pixel transistors as
described above, the wiring length of the FD wiring 31A of the
shared pixel 51 of the left column and the FD wiring 31B of the
shared pixel 51 of the right column become equal. Accordingly, a
difference in wiring capacitance between the FD wirings 31A and 31B
does not occur and a difference in conversion efficiency between
columns does not occur. As a result, a vertical stripe does not
occur.
[0142] In the case of using the color filters of the Bayer array,
by arranging the pixel transistors as described above, the gate
electrodes having the same area are included in the Gr pixel and
the Gb pixel. Accordingly, a difference in light absorption of the
gate electrodes formed of polysilicon between the Gr pixel and the
Gb pixel does not occur and a vertical stripe does not occur.
Accordingly, it is possible to provide a solid-state imaging device
having a longitudinal 4-pixel shared structure, in which a
difference in sensitivity between the shared pixels hardly
occurs.
8. Sixth Embodiment
Configuration Example of Solid-State Imaging Device
[0143] FIG. 14 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to a sixth embodiment of the
present invention. FIG. 14 shows the schematic configuration of the
main parts applied to the CMOS solid-state imaging device in which
pixel transistors of the 3-transistor type are provided and a
plurality of shared pixels having a longitudinal 2-pixel shared
structure is arranged. The arrangement of the pixel transistors and
the like of the present embodiment will be described in comparison
with Comparative Example 6 of FIG. 15.
[0144] FIG. 24 shows an equivalent circuit of the shared pixels
having pixel transistors of the 3-transistor type and the 2-pixel
shared structure. The portions corresponding to FIG. 22 are denoted
by the same reference numerals and the description thereof will be
omitted.
[0145] First, Comparative Example 6 of FIG. 15 will be described.
The solid-state imaging device according to Comparative Example 6
is completed by two-dimensionally arranging a plurality of shared
pixels 137 having a 2-pixel shared structure in which one floating
diffusion portion FD is shared between vertically (longitudinally)
neighboring two photodiodes PD1 and PD2. Transfer gate electrodes
are formed between the two photodiodes PD1 and PD2 and the floating
diffusion portion FD so as to form transfer transistors Tr11 and
Tr12. A reset transistor Tr2 and an amplification transistor Tr3
are arranged so as to be vertically divided with the two
photodiodes PD1 and PD2 interposed therebetween. The shared pixels
137 having the 2-pixel shared structure are formed of the two
photodiodes PD1 and PD2, one floating diffusion portion FD, two
transfer transistors Tr11 and Tr12, one reset transistor Tr2 and
one amplification transistor Tr3.
[0146] The reset transistor Tr2 includes a source region 104, a
drain region 105 and a reset gate electrode 106. The amplification
transistor Tr3 includes a source region 107, a drain region 108 and
an amplification gate electrode 109. In the shared pixels 137 of
the neighboring columns, the reset transistors Tr2 are lined up in
the same direction and arranged in the same row direction and the
amplification transistors Tr3 are lined up in the same direction
and arranged in the same row direction. In the shared pixels 137 of
the columns, the FD wirings 111 [111A and 111B] are electrically
connected to the source regions 104 of the reset transistors Tr2,
the floating diffusion portion FD and the amplification gate
electrodes 109.
[0147] In the solid-state imaging device 136 of Comparative Example
6, the wiring lengths of the FD wirings 111A and 111B of the
neighboring columns become equal. For example, in the case of using
the color filters of the Bayer array, a portion of the reset gate
electrode 106 is included in the Gr pixel and a portion of the
amplification gate electrode 109 is included in the Gb pixel. Since
the Gr pixel and the Gb pixel include respective gate electrodes
having different areas, a difference in light absorption of the
gate electrodes between the Gr pixel and the Gb pixel occurs. As a
result, a deviation in sensitivity between columns occurs and a
vertical stripe occurs.
[0148] Next, the solid-state imaging device according to the sixth
embodiment of the present invention will be described. As shown in
FIG. 14, the solid-state imaging device 53 according to the sixth
embodiment is completed by two-dimensionally arranging a plurality
of shared pixels 54 having a 2-pixel shared structure in which one
floating diffusion portion FD is shared between two vertically
(longitudinally) neighboring photodiodes PD1 and PD2. Transfer gate
electrodes TG1 and TG2 are formed between the two photodiodes PD1
and PD2 and the floating diffusion portion FD so as to form the
transfer transistors Tr11 and Tr12.
[0149] In the present embodiment, the reset transistor Tr2 and the
amplification transistor Tr3 are divisionally arranged on the upper
and lower side of the shared pixels 54. In addition, the reset
transistor Tr2 and the amplification transistor Tr3 are lined up
and arranged in the row direction on the upper side of the shared
pixels of the neighboring columns and the reset transistor Tr2 and
the amplification transistor Tr3 are arranged on the lower side
thereof such that the array thereof crosses the array of the upper
side. The reset transistor Tr2 includes a source region 24, a drain
region 25 and a reset gate electrode 26. The amplification
transistor Tr3 includes a source region 27, a drain region 28 and
an amplification gate electrode 29. In the shared pixels 54, the FD
wirings 31 [31A and 31B] are electrically connected to the source
regions 24 of the reset transistors Tr2, the floating diffusion
portion FD and the amplification gate electrodes 29.
[0150] According to the solid-state imaging device 53 according to
the sixth embodiment, in the 2-pixel shared configuration, the
reset transistor Tr2 and the amplification transistor Tr3 are
arranged so as to be vertically crossed between the shared pixels
54 of the neighboring columns. By this configuration, the wiring
length of the FD wiring 31A of the shared pixel 54 of the left
column and the FD wiring 31B of the shared pixel 54 of the right
column become equal. Accordingly, a difference in wiring
capacitance between the FD wirings 31A and 31B does not occur and a
difference in conversion efficiency between columns does not occur.
As a result, a vertical stripe does not occur.
[0151] In the case of using the color filters of the Bayer array,
by arranging the pixel transistors as described above, the gate
electrodes having the same area are included in the Gr pixel and
the Gb pixel. Accordingly, a difference in light absorption of the
gate electrodes formed of polysilicon between the Gr pixel and the
Gb pixel does not occur and a vertical stripe does not occur.
Accordingly, it is possible to provide a solid-state imaging device
having a 2-pixel shared structure, in which a difference in
sensitivity between the shared pixels hardly occurs.
9. Seventh Embodiment
Configuration Example of Solid-State Imaging Device
[0152] FIG. 16 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to a seventh embodiment of the
present invention. FIG. 16 shows the schematic configuration of
main portions applied to the CMOS solid-state imaging device in
which pixel transistors of the 4-transistor type are provided and a
plurality of shared pixels having a 2-pixel shared structure is
arranged. The arrangement of the pixel transistors and the like of
the present embodiment will be described in comparison with
Comparative Example 7 of FIG. 17.
[0153] FIG. 25 shows an equivalent circuit of the shared pixels
having pixel transistors of the 4-transistor type and the 2-pixel
shared structure. The portions corresponding to FIG. 23 are denoted
by the same reference numerals and the description thereof will be
omitted.
[0154] First, the solid-state imaging device according to
Comparative Example 7 of FIG. 17 will be described. In the
solid-state imaging device 139 of Comparative Example 7, a reset
transistor Tr2 and a serial circuit of an amplification transistor
Tr3 and a selection transistor Tr4 are divisionally arranged on the
upper and lower sides of the shared pixels 141. The reset
transistor Tr2 includes a source region 104, a drain region 105 and
a reset gate electrode 106. The serial circuit of the amplification
transistor Tr3 and the selection transistor Tr4 include three
diffusion regions 115, 116 and 117 which become the source/drain
regions, an amplification gate electrode 109 and a selection gate
electrode 118. In the shared pixels 141 of the neighboring columns,
the reset transistors Tr2 are arranged in the same direction and in
the same row direction and the serial circuit of the amplification
transistor Tr3 and the selection transistor Tr4 are arranged in the
same direction and the same row direction. Since the other
configuration is the same as that of FIG. 15, the portions
corresponding to FIG. 15 are denoted by the same reference numerals
and the description thereof will be omitted.
[0155] In the solid-state imaging device 139 of Comparative Example
7, the wiring length of the FD wirings 111A and 111B of the
neighboring columns become equal. For example, in the case of using
the color filters of the Bayer array, a portion of the reset gate
electrode 106 is included in the Gr pixel and a portion of the
amplification gate electrode 109 is included in the Gb pixel. Since
the Gr pixel and the Gb pixel include the gate electrodes having
different areas, a difference in light absorption of the gate
electrodes between the Gr pixel and the Gb pixel occurs and, as a
result, a deviation in sensitivity between columns occurs and a
vertical stripe occurs.
[0156] Next, the solid-state imaging device according to the
seventh embodiment will be described. In the solid-state imaging
device 56 according to the seventh embodiment, a reset transistor
Tr2 and a serial circuit of an amplification transistor Tr3 and a
selection transistor Tr4 are divisionally arranged on the upper and
lower sides of the shared pixels 57. Between the shared pixels of
the neighboring columns, the reset transistors Tr2 are arranged so
as to be vertically crossed and the serial circuits are arranged so
as to be vertical crossed. That is, the reset transistors Tr2 and
the serial circuits of the amplification transistor Tr3 and the
selection transistors Tr4 corresponding to the neighboring columns
are lined up and arranged in the row direction such that the array
thereof is arranged so as to be crossed on the upper side and the
lower side. The reset transistor Tr2 includes a source region 24, a
drain region 25 and a reset gate electrode 26. The serial circuit
of the amplification transistor Tr3 and the selection transistor
Tr4 includes three diffusion regions 35, 36 and 37 which become the
source/drain regions, an amplification gate electrode 29 and a
selection gate electrode 38.
[0157] Since the other configuration is the same as that of FIG.
14, the portions corresponding to FIG. 14 are denoted by the same
reference numerals and the description thereof will be omitted.
[0158] According to the solid-state imaging device 56 according to
the seventh embodiment, in the 2-pixel shared configuration, the
reset transistor Tr2 and the serial circuit of the amplification
transistor Tr3 and the selection transistor Tr4 are arranged so as
to be vertically crossed between the shared pixels 57 of the
neighboring columns. By this configuration, the wiring length of
the FD wiring 31A of the shared pixel 57 of the left column and the
FD wiring 31B of the shared pixel 57 of the right column become
equal. Accordingly, a difference in wiring capacitance between the
FD wirings 31A and 31B does not occur and a difference in
conversion efficiency between columns does not occur. As a result,
a vertical stripe does not occur.
[0159] In the case of using the color filters of the Bayer array,
by arranging the pixel transistors as described above, the gate
electrodes having the same area are included in the Gr pixel and
the Gb pixel. Accordingly, a difference in light absorption of the
gate electrodes formed of polysilicon between the Gr pixel and the
Gb pixel does not occur and a vertical stripe does not occur.
Accordingly, it is possible to provide a solid-state imaging device
having a 2-pixel shared structure, in which a difference in
sensitivity between the shared pixels hardly occurs.
10. Eighth Embodiment
Configuration Example of Solid-State Imaging Device
[0160] FIG. 18 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to an eighth embodiment of the
present invention. FIG. 18 shows the schematic configuration of
main portions applied to the CMOS solid-state imaging device in
which pixel transistors of the 3-transistor type are provided and a
plurality of shared pixels having a 2.times.2 pixel shared
structure, that is, a 4-pixel shared structure, is arranged. The
arrangement of the pixel transistors and the like of the present
embodiment will be described in comparison with Comparative Example
8 of FIG. 19.
[0161] FIG. 26 shows an equivalent circuit of the shared pixels
having pixel transistors of the 3-transistor type and the
2.times.2-pixel shared structure, that is, the 4-pixel shared
structure. The portions corresponding to FIG. 22 are denoted by the
same reference numerals and the description thereof will be
omitted.
[0162] First, the solid-state imaging device according to
Comparative Example 8 of FIG. 19 will be described. In the
solid-state imaging device 143 of Comparative Example 8, one
floating diffusion portion FD is shared between 2.times.2
photodiodes, that is, a total of four photodiodes PD [PD1 to PD4].
The pixel transistors are configured as the 3-transistor type of
four transfer transistors Tr1 [Tr11 to Tr14], one reset transistor
Tr2 and one amplification transistor Tr3. The shared pixels 144
having the 4-pixel shared structure are formed of the four
photodiodes PD1 to PD4, one floating diffusion portion FD, the
transfer transistors Tr11 to Tr14, the reset transistor Tr2 and the
amplification transistor Tr3.
[0163] Among the four transfer transistors Tr11 to Tr14, the
transfer gate electrodes of the transfer transistors Tr11 and Tr12
connected to two horizontal photodiodes PD1 and PD2 are formed of a
common gate electrode TG1. The transfer gate electrodes of the
transfer transistors Tr13 and Tr14 connected to two horizontal
photodiodes PD3 and PD4 are formed of a common gate electrode TG2.
The amplification transistor Tr3 and the reset transistor Tr2 are
divisionally arranged on the upper side and the lower side of the
shared pixels 144. In the vertically neighboring shared pixels 144,
the reset transistors Tr2 are arranged in the same row direction.
The amplification transistors Tr3 are arranged in the same row
direction.
[0164] The reset transistor Tr2 includes a source region 104, a
drain region 105 and a reset gate electrode 106. The amplification
transistor Tr3 includes a source region 107, a drain region 108 and
an amplification gate electrode 109. In the shared pixels, the
floating diffusion portion FD, the amplification gate electrode 109
and the source region 104 of the reset transistor are connected by
the FD wirings 111 [111A and 111B].
[0165] In the solid-state imaging device 143 of Comparative Example
8, the FD wirings 111A and 111B of the vertically neighboring
shared pixels 144 are formed along the column direction and the
wiring lengths thereof become equal. For example, in the case of
using the color filters of the Bayer array, a portion of the reset
gate electrode 106 is included in the Gr pixel and a portion of the
amplification gate electrode 109 is included in the Gb pixel. Since
the Gr pixel and the Gb pixel include respective gate electrodes
having different areas, a difference in light absorption of the
gate electrodes between the Gr pixel and the Gb pixel occurs. As a
result, a deviation in sensitivity between columns occurs and a
vertical stripe occurs.
[0166] Next, the solid-state imaging device according to the eighth
embodiment will be described. The solid-state imaging device 59
according to the eighth embodiment is configured by sharing one
floating diffusion portion FD among the 2.times.2 photodiodes, that
is, a total of four photodiodes PD [PD1 to PD4], as shown in FIG.
18. The pixel transistors are configured as the 3-transistor type
of the four transfer transistors Tr1 [Tr11 to Tr14], one reset
transistor Tr2 and one amplification transistor Tr3. The shared
pixels 61 having the 4-pixel shared structure are formed of the
four photodiodes PD1 to PD4, one floating diffusion portion FD, the
transfer transistors Tr11 to Tr14, the reset transistor Tr2 and the
amplification transistor Tr3.
[0167] Among the four transfer transistors Tr11 to Tr14, the
transfer gate electrodes of the transfer transistors Tr11 and Tr12
connected to two horizontal photodiodes PD1 and PD2 are formed of a
common gate electrode TG1. The transfer gate electrodes of the
transfer transistors Tr13 and Tr14 connected to two horizontal
photodiodes PD3 and PD4 are formed of a common gate electrode
TG2.
[0168] In the present embodiment, the two vertically neighboring
shared pixels are set as one and the reset transistor Tr2 and the
amplification transistor Tr3 are divisionally arranged on the upper
and lower sides in one set of shared pixels with the shared pixel
61 interposed therebetween. In one set, the reset transistor Tr2
and the amplification transistor Tr3 lined up and arranged in the
row direction so as to correspond to two shared pixels 61 are
arranged such that the arrays thereof are crossed on the upper side
and the lower side. The reset transistor Tr2 includes a source
region 34, a drain region 35 and a reset gate electrode 36. The
amplification transistor Tr3 includes a source region 27, a drain
region 28 and an amplification gate electrode 29.
[0169] In the shared pixels 61, the FD wirings 31 [31A and 31B] are
electrically connected to the source region 24 of the reset
transistor Tr2, the floating diffusion portion FD and the
amplification gate electrode 29. The FD wirings 31A and 31B of the
two vertically neighboring shared pixels 61 are arranged along the
column direction.
[0170] According to the solid-state imaging device 59 according to
the eighth embodiment, the reset transistor Tr2 and the
amplification transistor Tr3 lined up and arranged in the row
direction are arranged so as to be vertically crossed with the
shared pixels 61 interposed therebetween. Accordingly, the wiring
lengths of the FD wiring 31A and 31B of the vertically neighboring
shared pixels 61 become equal. Accordingly, a difference in wiring
capacitance between the FD wirings 31A and 31B does not occur and a
difference in conversion efficiency between columns does not occur.
As a result, a vertical stripe does not occur.
[0171] In the case of using the color filters of the Bayer array,
by arranging the pixel transistors as described above, the gate
electrodes having the same area are included in the Gr pixel and
the Gb pixel. Accordingly, a difference in light absorption of the
gate electrodes formed of polysilicon between the Gr pixel and the
Gb pixel does not occur and a vertical stripe does not occur.
Accordingly, it is possible to provide a solid-state imaging device
having a 2-pixel shared structure, in which a difference in
sensitivity between the shared pixels hardly occurs.
11. Ninth Embodiment
Configuration Example of Solid-State Imaging Device
[0172] FIG. 20 shows a solid-state imaging device, that is, a CMOS
solid-state imaging device according to a ninth embodiment of the
present invention. FIG. 20 shows the schematic configuration of
main portions applied to the CMOS solid-state imaging device in
which pixel transistors of the 4-transistor type are provided and a
plurality of shared pixels having a 2.times.2 pixel shared
structure, that is, a 4-pixel shared structure, is arranged. The
arrangement of the pixel transistors and the like of the present
embodiment will be described in comparison with Comparative Example
9 of FIG. 21.
[0173] FIG. 27 shows an equivalent circuit of the shared pixels
having pixel transistors of the 4-transistor type and the
2.times.2-pixel shared structure, that is, the 4-pixel shared
structure. The portions corresponding to FIG. 23 are denoted by the
same reference numerals and the description thereof will be
omitted.
[0174] First, the solid-state imaging device according to
Comparative Example 9 of FIG. 21 will be described. In the
solid-state imaging device 146 of Comparative Example 9, a serial
circuit of an amplification transistor Tr3 and a selection
transistor Tr4 and a reset transistor Tr2 are divisionally arranged
on the upper and lower sides with one shared pixel of the two
vertically neighboring shared pixels 147 interposed therebetween.
Two reset transistors Tr2 corresponding to the two shared pixels 64
are lined up and arranged in the same row direction. Two serial
circuits corresponding to the two shared pixels 64 are lined up and
arranged in the same row direction. The configuration of the serial
circuit of the amplification transistor Tr3 and the selection
transistor Tr4 is the same as that of FIG. 13 described above.
[0175] Since the other configuration is the same as that of FIG.
19, the portions corresponding to FIG. 19 are denoted by the same
reference numerals and the description thereof will be omitted.
[0176] In the solid-state imaging device 146 of Comparative Example
9, the FD wirings 111A and 111B of the vertically neighboring
shared pixels 147 are formed along the column direction and the
wiring lengths thereof become equal. For example, in the case of
using the color filters of the Bayer array, a portion of the reset
gate electrode 106 is included in the Gr pixel and a portion of the
amplification gate electrode 109 and the selection gate electrode
118 is included in the Gb pixel. Since the Gr pixel and the Gb
pixel include respective gate electrodes having different areas, a
difference in light absorption of the gate electrodes between the
Gr pixel and the Gb pixel occurs. As a result, a deviation in
sensitivity between columns occurs and a vertical stripe
occurs.
[0177] Next, the solid-state imaging device according to the ninth
embodiment will be described. In the solid-state imaging device 63
according to the ninth embodiment, as shown in FIG. 20, the serial
circuit of the amplification transistor Tr3 and the selection
transistor Tr4 and the reset transistor Tr2 are horizontally
reversed in the vertically neighboring shared pixels. The
horizontally reversed serial circuit and the reset transistor Tr2
are arranged so as to be vertically crossed. That is, two reset
transistors Tr2 in which the drain region 25 is commonly integrated
and two serial circuits in which the drain region of the
amplification transistor Tr3 is commonly integrated are arranged in
the row direction on the upper side of the vertically neighboring
shared pixel 64. The integrated reset transistor Tr2 and the serial
circuit are arranged on the lower side of the vertically
neighboring shared pixel 64 so as to become the array crossing the
array of the integrated serial circuit and reset transistor Tr2.
The configuration of the integrated serial circuit and the
integrated reset transistor Tr2 is the same as that described in
FIG. 5.
[0178] Since the other configuration is the same as that of FIG. 8,
the portions corresponding to FIG. 8 are denoted by the same
reference numerals and the description thereof will be omitted.
[0179] According to the solid-state imaging device 63 according to
the ninth embodiment, since the serial circuits and the reset
transistors Tr2 of the vertically neighboring two shared pixels 64
are arranged so as to be horizontally reversed and vertically
crossed, the wiring lengths of the FD wirings 31A and 31B of the
vertically neighboring shared pixels 61 become equal. Accordingly,
a difference in wiring capacitance between the FD wirings 31A and
31B does not occur and a difference in conversion efficiency
between columns does not occur. As a result, a vertical stripe does
not occur.
[0180] In the case of using the color filters of the Bayer array,
by arranging the pixel transistors as described above, the gate
electrodes having the same area are included in the Gr pixel and
the Gb pixel. Accordingly, a difference in light absorption of the
gate electrodes formed of polysilicon between the Gr pixel and the
Gb pixel does not occur and a vertical stripe does not occur.
Accordingly, it is possible to provide a solid-state imaging device
having a 2-pixel shared structure, in which a difference in
sensitivity between the shared pixels hardly occurs.
[0181] The solid-state imaging devices according to the
above-described embodiments of the present invention are applicable
to a front-illuminated type or a back-illuminated type.
12. Tenth Embodiment
Configuration Example of Electronic Apparatus
[0182] The above-described solid-state imaging devices according to
the present invention are applicable to, for example, electronic
apparatuses, such as digital still cameras, digital video cameras,
various mobile terminals such as mobile telephones including a
camera included therein, printers or the like.
[0183] FIG. 28 shows a camera, which is an example of an electronic
apparatus, according to a tenth embodiment of the present
invention. The camera according to the present embodiment is, for
example, a video camera capable of photographing a still image or a
moving image. The camera 71 of the present embodiment includes a
solid-state imaging device 72, an optical system 73 for guiding
incident light to a light-receiving sensor unit of the solid-state
imaging device 72, and a shutter device 74. The camera 71 further
includes a driving circuit 75 for driving the solid-state imaging
device 72 and a signal processing circuit 76 for processing an
output signal of the solid-state imaging device 72.
[0184] As the solid-state imaging device 72, any one of the
solid-state imaging devices of the above-described embodiments is
applied. The optical system (optical lens) 73 images image light
(incident light) from a subject on a imaging surface of the
solid-state imaging device 72 and the optical system 73 may be an
optical lens system including a plurality of optical lenses. The
shutter device 74 controls a light irradiation period and a light
shielding period of the solid-state imaging device 72. The driving
circuit 75 supplies a driving signal for controlling a transmission
operation of the solid-state imaging device 72 and a shutter
operation of the shutter device 74. Signal transmission of the
solid-state imaging device 72 is performed by the driving signal
(timing signal) supplied from the driving circuit 75. The signal
processing circuit 76 performs a variety of signal processes. A
signal-processed image signal is stored in a storage medium such as
a memory or is output to a monitor.
[0185] According to the electronic apparatus such as the camera
according to the tenth embodiment, in the solid-state imaging
device 72 having shared pixels, since a difference in sensitivity
between the shared pixels hardly occurs, it is possible to obtain
high quality and to provide an electronic apparatus with high
reliability.
[0186] The present application contains subject matter related to
that disclosed in Japanese Priority Patent Application JP
2010-017019 filed in the Japan Patent Office on Jan. 28, 2010, the
entire contents of which are hereby incorporated by reference.
[0187] It should be understood by those skilled in the art that
various modifications, combinations, sub-combinations and
alterations may occur depending on design requirements and other
factors insofar as they are within the scope of the appended claims
or the equivalents thereof.
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