U.S. patent application number 17/136296 was filed with the patent office on 2021-05-20 for imaging element, solid state imaging device, and electronic device.
This patent application is currently assigned to SONY CORPORATION. The applicant listed for this patent is SONY CORPORATION. Invention is credited to Toshiki MORIWAKI.
Application Number | 20210151614 17/136296 |
Document ID | / |
Family ID | 1000005371142 |
Filed Date | 2021-05-20 |
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United States Patent
Application |
20210151614 |
Kind Code |
A1 |
MORIWAKI; Toshiki |
May 20, 2021 |
IMAGING ELEMENT, SOLID STATE IMAGING DEVICE, AND ELECTRONIC
DEVICE
Abstract
An imaging element includes a first electrode, a second
electrode, and a light receiving layer between the first electrode
and the second electrode to receive incident light from the second
electrode. The second electrode includes an indium-tin oxide layer
which includes at least one of silicon or silicon oxide.
Inventors: |
MORIWAKI; Toshiki;
(Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SONY CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
SONY CORPORATION
Tokyo
JP
|
Family ID: |
1000005371142 |
Appl. No.: |
17/136296 |
Filed: |
December 29, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16343516 |
Apr 19, 2019 |
10937913 |
|
|
PCT/JP2017/038489 |
Oct 25, 2017 |
|
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17136296 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/02565 20130101;
H01L 33/42 20130101; H01L 27/14643 20130101; H01L 27/14665
20130101; H01L 31/022475 20130101; H01L 27/307 20130101; H01L
31/022466 20130101 |
International
Class: |
H01L 31/0224 20060101
H01L031/0224; H01L 33/42 20060101 H01L033/42; H01L 21/02 20060101
H01L021/02; H01L 27/146 20060101 H01L027/146 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2016 |
JP |
2016-215162 |
Claims
1. An imaging element comprising: a stacked structure including a
first electrode, a light receiving layer formed on the first
electrode, and a second electrode formed on the light receiving
layer, and configured such that light is incident from the second
electrode, wherein the second electrode includes an amorphous
indium-tin oxide doped or mixed with at least one material selected
from the group including cobalt, cobalt oxide, tungsten, tungsten
oxide, zinc, or zinc oxide.
2. The imaging element according to claim 1, wherein the second
electrode has absorption characteristics of 20% or more at a
wavelength of 300 nm and 15% or more at a wavelength of 350 nm.
3. The imaging element according to claim 1, wherein a thickness of
the second electrode is 1.times.10.sup.-8 m to 1.5.times.10.sup.-7
m.
4. The imaging element according to claim 1, wherein the at least
one material is mixed or doped at 5 mass % or less in the second
electrode.
5. The imaging element according to claim 1, wherein the at least
one material is mixed or doped at 1 mass % or more and 3 mass % or
less in the second electrode.
6. The imaging element according to claim 1, wherein a surface
roughness Ra of the second electrode is 0.5 nm or less, and a
surface roughness Rq of the second electrode is 0.5 nm or less.
7. The imaging element according to claim 1, wherein light
transmittance of the second electrode for light of wavelengths of
400 nm to 660 nm is 65% or more.
8. The imaging element according to claim 1, wherein an electric
resistance value of the second electrode is 1.times.10.sup.6
.OMEGA.cm or less.
9. The imaging element according to claim 1, wherein a sheet
resistance value of the second electrode is
3.times.10.OMEGA./.quadrature. to
1.times.10.sup.3.OMEGA./.quadrature..
10. The imaging element according to claim 1, wherein the stacked
structure has an internal stress of compressive stress of 10 MPa to
50 MPa.
11. The imaging element according to claim 1, wherein the first
electrode includes an amorphous indium-tin oxide mixed or doped
with at least one material selected from the group including
silicon, silicon oxide, cobalt, cobalt oxide, tungsten, tungsten
oxide, zinc, or zinc oxide.
12. A solid-state imaging device comprising: a plurality of imaging
elements, wherein each of the plurality of imaging elements
includes a stacked structure including a first electrode, a light
receiving layer formed on the first electrode, and a second
electrode formed on the light receiving layer, and configured such
that light is incident from the second electrode, wherein the
second electrode includes an amorphous indium-tin oxide doped or
mixed with at least one material selected from the group including
cobalt, cobalt oxide, tungsten, tungsten oxide, zinc, or zinc
oxide.
13. An electronic device comprising: a stacked structure including
a first electrode, a light emitting/light receiving layer formed on
the first electrode, and a second electrode formed on the light
emitting/light receiving layer, and configured such that light is
incident from the second electrode, wherein the second electrode
includes an amorphous indium-tin oxide doped or mixed with at least
one material selected from the group including cobalt, cobalt
oxide, tungsten, tungsten oxide, zinc, or zinc oxide.
14. The electronic device according to claim 13, wherein the second
electrode has absorption characteristics of 20% or more at a
wavelength of 300 nm and 15% or more at a wavelength of 350 nm.
15. The electronic device according to claim 13, wherein a
thickness of the second electrode is 1.times.10.sup.-8 m to
1.5.times.10.sup.-7 m.
16. The electronic device according to claim 13, wherein the at
least one material is mixed or doped at 5 mass % or less in the
second electrode.
17. The electronic device according to claim 13, wherein the at
least one material is mixed or doped at 1 mass % or more and 3 mass
% or less in the second electrode.
18. The electronic device according to claim 13, wherein a surface
roughness Ra of the second electrode is 0.5 nm or less, and a
surface roughness Rq of the second electrode is 0.5 nm or less.
19. The electronic device according to claim 13, wherein light
transmittance of the second electrode for light of wavelengths of
400 nm to 660 nm is 65% or more.
20. The electronic device according to claim 13, wherein an
electric resistance value of the second electrode is
1.times.10.sup.-6 .OMEGA.cm or less.
21. The electronic device according to claim 13, wherein a sheet
resistance value of the second electrode is
3.times.10.OMEGA./.quadrature. to
1.times.10.sup.3.OMEGA./.quadrature..
22. The electronic device according to claim 13, wherein the
stacked structure has an internal stress of compressive stress of
10 MPa to 50 MPa.
23. The electronic device according to claim 13, wherein the first
electrode includes an amorphous indium-tin oxide mixed or doped
with at least one material selected from the group including
silicon, silicon oxide, cobalt, cobalt oxide, tungsten, tungsten
oxide, zinc, or zinc oxide.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 16/343,516 filed Apr. 19, 2019, which
is a national stage application under 35 U.S.C. 371 and claims the
benefit of PCT Application No. PCT/JP2017/038489 having an
international filing date of 25 Oct. 2017, which designated the
United States, which PCT application claimed the benefit of
Japanese Patent Application No. 2016-215162 filed 2 Nov. 2016, the
entire disclosures of each of which are incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present disclosure relates to an imaging element, a
solid state imaging device, and an electronic device.
BACKGROUND ART
[0003] An imaging element included in an image sensor or the like
has a structure in which, for example, a light receiving layer (a
photoelectric conversion layer) is sandwiched by two electrodes. In
such an imaging element, the transparent electrode on which light
is incident is usually formed of a transparent conductive material
of an indium-tin oxide (ITO) having crystallinity. However, such a
transparent electrode made of an ITO has large internal stress, and
often causes a characteristic reduction of the imaging element. An
imaging element (photoelectric conversion element) for solving the
problem derived from the internal stress of such a transparent
electrode is known from, for example, JP 2010-003901A. That is, the
imaging element (photoelectric conversion element) disclosed in
this Japanese Unexamined Patent Application Publication includes a
photoelectric conversion layer placed between a pair of electrodes
and at least one stress buffer layer sandwiched by one of the pair
of electrodes and the photoelectric conversion layer; in the
imaging element, the stress buffer layer has a stacked structure
including crystal layers, specifically, a structure in which two
crystal layers and two amorphous layers (a total of four layers)
are alternately stacked.
CITATION LIST
Patent Literature
[PTL 1]
JP 2010-003901A
SUMMARY
Technical Problem
[0004] However, in the technology disclosed in Japanese Unexamined
Patent Application Publication mentioned above, the stress buffer
layer has an at least four-layer configuration and the structure is
complicated; therefore, there is a problem that the formation
process is complicated and the formation of the stress buffer layer
takes a long time.
[0005] Thus, it is desirable to provide an imaging element having a
configuration and a structure that do not cause a characteristic
reduction in spite of a simple structure, a solid state imaging
device including the imaging element, and an electronic device.
Solution to Problem
[0006] An imaging element according to a first embodiment of the
present disclosure includes: a stacked structure body composed of a
first electrode, a light receiving layer formed on the first
electrode, and a second electrode formed on the light receiving
layer, and configured such that light is incident from the second
electrode. The second electrode is made of an amorphous oxide made
of an indium-tin oxide in which at least one material selected from
the group consisting of silicon and a silicon oxide is mixed or
doped.
[0007] An imaging element according to a second embodiment of the
present disclosure includes: a stacked structure body composed of a
first electrode, a light receiving layer formed on the first
electrode, and a second electrode formed on the light receiving
layer, and configured such that light is incident from the second
electrode. The second electrode is made of an amorphous oxide made
of an indium-tin oxide in which at least one material selected from
the group consisting of cobalt, a cobalt oxide, tungsten, a
tungsten oxide, zinc, and a zinc oxide is mixed or doped.
[0008] A solid state imaging device according to the first
embodiment of the present disclosure includes a plurality of
imaging elements. Each of the imaging elements includes a stacked
structure body composed of a first electrode, a light receiving
layer formed on the first electrode, and a second electrode formed
on the light receiving layer, and configured such that light is
incident from the second electrode, and the second electrode is
made of an amorphous oxide made of an indium-tin oxide in which at
least one material selected from the group consisting of silicon
and a silicon oxide is mixed or doped.
[0009] A solid state imaging device according to the second
embodiment of the present disclosure includes a plurality of
imaging elements. Each of the imaging elements includes a stacked
structure body composed of a first electrode, a light receiving
layer formed on the first electrode, and a second electrode formed
on the light receiving layer, and configured such that light is
incident from the second electrode, and the second electrode is
made of an amorphous oxide made of an indium-tin oxide in which at
least one material selected from the group consisting of cobalt, a
cobalt oxide, tungsten, a tungsten oxide, zinc, and a zinc oxide is
mixed or doped.
[0010] An electronic device according to the first embodiment of
the present disclosure includes: a stacked structure body composed
of a first electrode, a light emitting/light receiving layer formed
on the first electrode, and a second electrode formed on the light
emitting/light receiving layer, and configured such that light is
incident from the second electrode. The second electrode is made of
an amorphous oxide made of an indium-tin oxide in which at least
one material selected from the group consisting of silicon and a
silicon oxide is mixed or doped.
[0011] An electronic device according to the second embodiment of
the present disclosure includes: a stacked structure body composed
of a first electrode, a light emitting/light receiving layer formed
on the first electrode, and a second electrode formed on the light
emitting/light receiving layer, and configured such that light is
incident from the second electrode. The second electrode is made of
an amorphous oxide made of an indium-tin oxide in which at least
one material selected from the group consisting of cobalt, a cobalt
oxide, tungsten, a tungsten oxide, zinc, and a zinc oxide is mixed
or doped.
Advantageous Effects of Invention
[0012] In the imaging element, the solid state imaging device, or
the electronic device according to the first embodiment or the
second embodiment of the present disclosure, since the second
electrode is not configured from an ITO but is configured from an
amorphous oxide in which the constituent materials are prescribed,
the internal stress in the second electrode is reduced; thus, an
imaging element, an electronic device, and a solid state imaging
device having high reliability in which, in spite of a simple
configuration and a simple structure, there is no fear that a
characteristic reduction of the imaging element, the electronic
device, or the solid state imaging device will be caused can be
provided. Further, since the second electrode is configured from an
amorphous oxide, the entry of water can be prevented (or
alternatively, reduced), and an imaging element, an electronic
device, and a solid state imaging device having high reliability
can be provided. The effects described in this specification are
only examples and are not limitative ones, and there may be
additional effects.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1A is a schematic partial cross-sectional view of a
substrate etc. for describing a method for manufacturing an imaging
element etc. of Example 1.
[0014] FIG. 1B is a schematic partial cross-sectional view of a
substrate etc. for describing a method for manufacturing an imaging
element etc. of Example 1.
[0015] FIG. 2A is a graph showing the relationship between the
wavelength of incident light and the light transmittance in imaging
elements etc. of Example 1 in which the second electrode is
configured from ITO-SiO.sub.X-based materials and an imaging
element of Comparative Example 1 in which the second electrode is
configured from an ITO and an IZO.
[0016] FIG. 2B is a graph showing the relationship between the
wavelength of incident light and the absorption characteristic in
imaging elements etc. of Example 1 in which the second electrode is
configured from ITO-SiO.sub.X-based materials and an imaging
element of Comparative Example 1 in which the second electrode is
configured from an ITO and an IZO.
[0017] FIG. 3A is a surface SEM image of the second electrode in
Example 1A (provided that it is a product of annealing treatment at
250.degree. C. for 1 hour in a nitrogen atmosphere).
[0018] FIG. 3B is a surface SEM image of the second electrode in
Comparative Example 1 (provided that it is a product of annealing
treatment at 250.degree. C. for 1 hour in a nitrogen
atmosphere).
[0019] FIG. 4 is charts showing the X-ray diffraction analysis
results of the second electrodes in Example 1.
[0020] FIG. 5 is a chart showing the X-ray diffraction analysis
result of the second electrode in Comparative Example 1.
[0021] FIG. 6 is a conceptual diagram of a solid state imaging
device of Example 2.
[0022] FIG. 7 is a diagram showing the configuration of the solid
state imaging device of Example 2.
DESCRIPTION OF EMBODIMENTS
[0023] Hereinbelow, embodiments of the present disclosure are
described based on Examples with reference to the drawings; but the
present disclosure is not limited to Examples, and the various
numerical values and materials in Examples are only examples.
[0024] 1. Overall description of imaging element, solid state
imaging device, and electronic device according to first embodiment
and second embodiment of present disclosure 2. Example 1 (imaging
element and electronic device according to first embodiment and
second embodiment of present disclosure)
[0025] 3. Example 2 (solid state imaging device according to first
embodiment and second embodiment of present disclosure)
[0026] 4. Other items
<Overall Description of Imaging Element, Solid State Imaging
Device, and Electronic Device According to First Embodiment and
Second Embodiment of Present Disclosure>
[0027] The imaging element according to the first embodiment of the
present disclosure, the imaging element in the solid state imaging
device according to the first embodiment of the present disclosure,
and the electronic device according to the first embodiment of the
present disclosure may be hereinafter collectively referred to as
"the imaging element etc. according to the first embodiment of the
present disclosure," and the imaging element according to the
second embodiment of the present disclosure, the imaging element in
the solid state imaging device according to the second embodiment
of the present disclosure, and the electronic device according to
the second embodiment of the present disclosure may be hereinafter
collectively referred to as "the imaging element etc. according to
the second embodiment of the present disclosure."
[0028] Further, the imaging element etc. according to the first
embodiment of the present disclosure and the imaging element etc.
according to the second embodiment of the present disclosure may be
collectively referred to as simply "the imaging element etc. of an
embodiment of the present disclosure."
[0029] In the imaging element etc. of an embodiment of the present
disclosure, the second electrode desirably has an absorption
characteristic (an ultraviolet absorption characteristic) of 20% or
more and preferably 35% or more at a wavelength of 300 nm, and
furthermore desirably has an absorption characteristic of 15% or
more and preferably 20% or more at a wavelength of 350 nm. By the
second electrode having such absorption characteristics, the second
electrode absorbs ultraviolet light incident on the second
electrode; consequently, the arrival of ultraviolet light at the
light receiving layer or the light emitting/light receiving layer
(hereinafter, these are collectively referred to as "the light
emitting layer etc.") can be suppressed. Then, as a result, the
increase in dark current in the imaging element and the electronic
device, the occurrence of in-plane unevenness of dark current in
the solid state imaging device, and the worsening of afterimage
characteristics can be suppressed. In addition, such ultraviolet
light is used in the patterning process of the second electrode,
alternatively used at the time of forming various films and layers
in the chemical vapor deposition method (the CVD method), or
alternatively used at the time of forming on-chip microlenses, for
example.
[0030] In the imaging element etc. of an embodiment of the present
disclosure including the preferred forms mentioned above, the
thickness of the second electrode is 1.times.10.sup.-8 m to
1.5.times.10.sup.-7 m, preferably 2.times.10.sup.-8 m to
1.times.10.sup.-7 m, and more preferably 3.times.10.sup.-8 m to
5.times.10.sup.-8 m. By thus prescribing the thickness of the
second electrode, light (light other than ultraviolet light) can be
caused to reach the light receiving layer etc. via the second
electrode still more reliably, and furthermore the second electrode
can exhibit a function as an electrode reliably.
[0031] In the imaging element etc. of an embodiment of the present
disclosure including the preferred forms described above, a form in
which the material mentioned above is mixed or doped at 5 mass % or
less and preferably 1 mass % or more and 3 mass % or less in the
second electrode is possible.
[0032] Alternatively, in the imaging element etc. of an embodiment
of the present disclosure, in a case where the second electrode is
configured from an indium-tin oxide in which silicon is mixed or
doped (an ITO-Si-based material), in a case where the second
electrode is configured from an indium-tin oxide in which a silicon
oxide is mixed or doped (an ITO-SiO.sub.X-based material), or in a
case where the second electrode is configured from an indium-tin
oxide in which silicon and a silicon oxide are mixed or doped (an
ITO-Si--SiO.sub.X-based material), the ratio of silicon atoms is
preferably 1 atomic % to 5 atomic % on the assumption that the
total amount of indium atoms, tin atoms, and silicon atoms is 100
atomic %. In a case where the second electrode is configured from
an indium-tin oxide in which cobalt is mixed or doped (an
ITO-Co-based material), in a case where the second electrode is
configured from an indium-tin oxide in which a cobalt oxide is
mixed or doped (an ITO-CoO.sub.X-based material), or in a case
where the second electrode is configured from an indium-tin oxide
in which cobalt and a cobalt oxide are mixed or doped (an
ITO-Co--CoO.sub.X-based material), the ratio of cobalt atoms is
preferably 10 atomic % to 20 atomic % on the assumption that the
total amount of indium atoms, tin atoms, and cobalt atoms is 100
atomic %. In a case where the second electrode is configured from
an indium-tin oxide in which tungsten is mixed or doped (an
ITO-W-based material), in a case where the second electrode is
configured from an indium-tin oxide in which a tungsten oxide is
mixed or doped (an ITO-WO.sub.X-based material), or in a case where
the second electrode is configured from an indium-tin oxide in
which tungsten and a tungsten oxide are mixed or doped (an
ITO-W--WO.sub.X-based material), the ratio of tungsten atoms is
preferably 5 atomic % to 20 atomic % on the assumption that the
total amount of indium atoms, tin atoms, and tungsten atoms is 100
atomic %. In a case where the second electrode is configured from
an indium-tin oxide in which zinc is mixed or doped (an
ITO-Zn-based material), in a case where the second electrode is
configured from an indium-tin oxide in which a zinc oxide is mixed
or doped (an ITO-ZnO.sub.X-based material), or in a case where the
second electrode is configured from an indium-tin oxide in which
zinc and a zinc oxide are mixed or doped (an ITO-Z--ZnO.sub.X-based
material), the ratio of zinc atoms is preferably 5 atomic % to 20
atomic % on the assumption that the total amount of indium atoms,
tin atoms, and zinc atoms is 100 atomic %. However, the ratios are
not limited to these values. Further, the various materials
described above are transparent conductive materials.
[0033] Further, in the imaging element etc. of an embodiment of the
present disclosure including the preferred forms described above,
the surface roughness Ra of the second electrode is 0.5 nm or less
and preferably 0.3 nm or less, and the surface roughness Rq of the
second electrode is 0.5 nm or less and preferably 0.3 nm or less.
The surface roughnesses Ra and Rq are based on the provision of JIS
B06 01-2013. The smoothness of the second electrode like this can
suppress the surface scattering reflection at the second electrode,
can reduce the surface reflection of light incident on the second
electrode, can suppress the loss of the amount of light incident on
the light receiving layer etc. via the second electrode, and can
achieve an improvement in light current characteristics in
photoelectric conversion.
[0034] Further, in the imaging element etc. of an embodiment of the
present disclosure including the preferred forms described above,
the light transmittance of the second electrode for light of
wavelengths of 400 nm to 660 nm is preferably 65% or more. Further,
also the light transmittance of the first electrode for light of
wavelengths of 400 nm to 660 nm is preferably 65% or more.
[0035] Further, in the imaging element etc. according to the
embodiment of the present disclosure including the preferred forms
described above, it is preferable that the electric resistance
value of the second electrode be 1.times.10.sup.-6 .OMEGA.cm or
less. Alternatively, it is preferable that the sheet resistance
value of the second electrode be 3.times.10.OMEGA./.quadrature. to
1.times.10.sup.3.OMEGA./.quadrature..
[0036] Further, in the imaging element etc. of an embodiment of the
present disclosure including the preferred forms described above,
the first electrode is preferably made of an amorphous oxide made
of an indium-tin oxide in which at least one material selected from
the group consisting of silicon, a silicon oxide, cobalt, a cobalt
oxide, tungsten, a tungsten oxide, zinc, and a zinc oxide is mixed
or doped. Alternatively, the first electrode may be a form
configured from a transparent conductive material such as an
indium-tin oxide (ITO), an indium-SiO.sub.X oxide (IZO), or tin
oxide (SnO.sub.2). As the method for forming the first electrode,
depending on the material that forms the first electrode, PVD
methods such as the vacuum deposition method, the reactive
deposition method, various sputtering methods, the electron beam
evaporation method, and the ion plating method, various CVD methods
such as the pyrosol method, a method of pyrolyzing an
organometallic compound, the spraying method, the dipping method,
and the MOCVD method, the electroless plating method, and the
electrolytic plating method may be given.
[0037] In the imaging element etc. according to the embodiment of
the present disclosure including the various preferred forms
described above, the stacked structure body is preferably in a form
having an internal stress of compressive stress of 10 MPa to 50
MPa; thereby, during the formation of the second electrode, the
occurrence of stress damage in the light receiving layer etc. can
be suppressed still more reliably.
[0038] In the imaging element etc. of an embodiment of the present
disclosure including the various preferred forms described above, a
form in which, when the value of the dark current flowing between
the first electrode and the second electrode when 0 volts is
applied between the first electrode and the second electrode is
denoted by J.sub.d-0 (amperes) and the value of the dark current
flowing between the first electrode and the second electrode when 5
volts is applied between the first electrode and the second
electrode is denoted by J.sub.d-5 (amperes),
J.sub.d-5/J.sub.d-0.ltoreq.1.2 is satisfied is possible. Further,
when the value of the dark current flowing between the first
electrode and the second electrode when a voltage more than 0 volts
and 5 volts or less is applied between the first electrode and the
second electrode is denoted by J.sub.d (amperes),
J.sub.d/J.sub.d-0.ltoreq.1.2 is satisfied. Here, the dark current
can be found by measuring the current flowing between the first
electrode and the second electrode when a reverse bias voltage is
applied between the first electrode and the second electrode in a
state where light is not applied, specifically, in a state of a
dark place.
[0039] By the electronic device according to the first embodiment
or the second embodiment of the present disclosure, a light sensor
or an image sensor can be formed. In this case, the light
emitting/light receiving layer may be formed of, for example, an
organic photoelectric conversion material.
[0040] In the imaging element etc. of an embodiment of the present
disclosure, the reception or the emission/reception of light (more
widely, electromagnetic waves, including visible light, ultraviolet
light, and infrared light) in the light receiving layer etc. is
performed via the second electrode.
[0041] In the electronic device of an embodiment of the present
disclosure including the various preferred forms and configurations
described above, specifically for example, a configuration in which
the first electrode is formed on a substrate, the light receiving
layer etc. is formed on the first electrode, and the second
electrode is formed on the light receiving layer etc. is possible.
That is, the electronic device of an embodiment of the present
disclosure has a two-terminal electronic device structure including
the first electrode and the second electrode. However, the
configuration is not limited to this, and a three-terminal
electronic device structure further including a control electrode
is possible, and thereby the current flowing can be modulated by
applying a voltage to the control electrode. As the three-terminal
electronic device structure, specifically, the same configuration
and structure as a field effect transistor (FET) of what is called
a bottom gate/bottom contact type, a bottom gate/top contact type,
a top gate/bottom contact type, or a top gate/top contact type may
be given. The second electrode may be made to function as a cathode
electrode (negative electrode) (that is, made to function as an
electrode for extracting electrons), and on the other hand the
first electrode may be made to function as an anode electrode
(positive electrode) (that is, made to function as an electrode for
extracting holes). Also a structure in which a plurality of imaging
elements or electronic devices including light receiving layers
etc. having different light absorption spectra are stacked may be
employed. Further, for example, a structure in which the substrate
is formed of a silicon semiconductor substrate, a driving circuit,
a light receiving layer, etc. of the imaging element or the
electronic device are provided in the silicon semiconductor
substrate, and imaging elements or electronic devices according to
the first embodiment or the second embodiment of the present
disclosure are stacked on the silicon semiconductor substrate may
be employed.
[0042] The light receiving layer etc. may be in an amorphous state
or a crystalline state. As the organic material that forms the
light receiving layer etc. (organic photoelectric conversion
material), an organic semiconductor material, an organometallic
compound, and organic semiconductor fine particles may be given; or
as the material that forms the light receiving layer etc., also a
metal oxide semiconductor, inorganic semiconductor fine particles,
a material in which a core member is coated with a shell member,
and an organic-inorganic hybrid compound may be given.
[0043] Here, as the organic semiconductor material, specifically,
an organic coloring agent typified by quinacridone and a derivative
thereof, a coloring agent in which an ion of the earlier period
(referring to the metals on the left side of the periodic table) is
chelated with an organic material, typified by Alq3
(tris(8-quinolinolato)aluminum (III)), an organometallic dye
complexed by a transition metal ion and an organic material,
typified by zinc (II) phthalocyanine, dinaphthothienothiophene
(DNTT), and the like may be given.
[0044] As the organometallic compound, specifically, the coloring
agent in which an ion of the earlier period is chelated with an
organic material and the organometallic dye complexed by a
transition metal ion and an organic material described above may be
given. As the organic semiconductor fine particles, specifically,
associated bodies of the organic coloring agent typified by
quinacridone and a derivative thereof described above, associated
bodies of a coloring agent in which an ion of the earlier period is
chelated with an organic material, associated bodies of an
organometallic dye complexed by a transition metal ion and an
organic material, or Prussian blue, in which metal ions are
cross-linked by a cyano group, and a derivative thereof, or
composite associated bodies of these may be given.
[0045] As the metal oxide semiconductor or the inorganic
semiconductor fine particles, specifically, ITO, IGZO, ZnO, IZO,
IrO.sub.2, TiO.sub.2, SnO.sub.2, SiO.sub.X, a metal chalcogenide
semiconductor containing a chalcogen (e.g. sulfur (S), selenium
(Se), or tellurium (Te)) (specifically, CdS, CdSe, ZnS, CdSe/CdS,
CdSe/ZnS, or PbSe), ZnO, CdTe, GaAs, and Si may be given.
[0046] As the combination of the material in which a core member is
coated with a shell member, that is, (core member, shell member),
specifically, an organic material such as (polystyrene,
polyaniline) and a metal material such as (a hardly ionizable metal
material, an easily ionizable metal material) may be given. As the
organic-inorganic hybrid compound, specifically, Prussian blue, in
which metal ions are cross-linked by a cyano group, and a
derivative thereof may be given, and in addition a coordination
polymer, which is a general term of materials in which metal ions
are infinitely cross-linked by a bipyridine and materials in which
metal ions are cross-linked by a polyvalent ionic acid typified by
oxalic acid and rubeanic acid, may be given.
[0047] As the method for forming the light receiving layer etc.,
depending on the material used, the application method, the
physical vapor deposition method (the PVD method), and various
chemical vapor deposition methods (CVD methods) including the MOCVD
method may be given. Here, as the application method, specifically,
the spin coating method; the immersion method; the casting method;
various printing methods such as the screen printing method, the
inkjet printing method, the offset printing method, and the gravure
printing method; the stamping method; the spraying method; and
various coating methods such as the air doctor coating method, the
blade coating method, the rod coating method, the knife coating
method, the squeeze coating method, the reverse roll coating
method, the transfer roll coating method, the gravure coating
method, the kiss coating method, the cast coating method, the spray
coating method, the slit orifice coating method, and the calender
coating method may be illustrated. In the application method, as
the solvent, a non-polar or low-polar organic solvent such as
toluene, chloroform, hexane, or ethanol may be illustrated. As the
PVD method, various vacuum deposition methods such as the electron
beam heating method, the resistance heating method, and flash
evaporation; the plasma deposition method; various sputtering
methods such as the dipole sputtering method, the direct current
sputtering method, the direct current magnetron sputtering method,
the radio-frequency sputtering method, the magnetron sputtering
method, the ion beam sputtering method, and the bias sputtering
method; and various ion plating methods such as the DC (direct
current) method, the RF method, the multi-cathode method, the
activated reaction method, the electric field deposition method,
the radio-frequency ion plating method, and the reactive ion
plating method may be given.
[0048] The thickness of the light receiving layer etc. is not
limited, and 1.times.10.sup.-10 m to 5.times.10.sup.-7 m may be
illustrated, for example.
[0049] As the substrate, an organic polymer such as polymethyl
methacrylate (PMMA), polyvinyl alcohol (PVA), a polyvinyl phenol
(PVP), a poly(ether sulfone) (PES), a polyimide, a polycarbonate
(PC), polyethylene terephthalate (PET), and polyethylene
naphthalate (PEN) (having a form of a polymer material such as a
plastic film, a plastic sheet, or a plastic substrate formed of a
polymer material and having flexibility) may be given. When a
substrate formed of such a polymer material having flexibility is
used, the electronic device can be incorporated into or integrated
with an electronic apparatus having, for example, a curved surface
shape. Alternatively, as the substrate, various glass substrates,
various glass substrates with an insulating film formed on their
surface, a quartz substrate, a quartz substrate with an insulating
film formed on its surface, a silicon semiconductor substrate, a
silicon semiconductor substrate with an insulating film formed on
its surface, and metal substrates made of various alloys and/or
various metals such as stainless steel may be given. As the
insulating film, a silicon oxide-based material (e.g. SiO.sub.X or
spin-on glass (SOG)); silicon nitride (SiN.sub.Y); silicon
oxynitride (SiON); aluminum oxide (Al.sub.2O.sub.3); and a metal
oxide and a metal salt may be given. Also an electrically
conductive substrate (a substrate made of a metal such as gold or
aluminum or a substrate made of highly oriented graphite) with any
of these insulating films formed on its surface may be used. The
surface of the substrate is preferably smooth, but may have a
roughness that does not adversely influence the characteristics of
the light receiving layer etc. The adhesion between the first
electrode and the substrate may be improved by forming a silanol
derivative formed by the silane coupling method, forming a thin
film made of a thiol derivative, a carboxylic acid derivative, a
phosphoric acid derivative, or the like formed by the SAM method or
the like, or forming a thin film made of an insulating metal salt
or metal complex formed by the CVD method or the like, on the
surface of the substrate.
[0050] The second electrode or the first electrode may be coated
with a coating layer depending on the circumstances. As the
material that forms the coating layer, a silicon oxide-based
material; silicon nitride (SiN.sub.Y); and an inorganic-based
insulating material such as a metal oxide high dielectric
insulating film of aluminum oxide (Al.sub.2O.sub.3) or the like may
be given; further, polymethyl methacrylate (PMMA); a polyvinyl
phenol (PVP); polyvinyl alcohol (PVA); a polyimide; a polycarbonate
(PC); polyethylene terephthalate (PET); polystyrene; a silanol
derivative (a silane coupling agent) such as
N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS),
3-mercaptopropyltrimethoxysilane (MPTMS), and
octadecyltrichlorosilane (OTS); and an organic-based insulating
material (an organic polymer) such as a linear hydrocarbon having a
functional group capable of binding to the control electrode at one
end, such as octadecanethiol and dodecyl isocyanate, may be given;
and further, combinations of these may be used. As the silicon
oxide-based material, silicon oxide (SiO.sub.X), BPSG, PSG, BSG,
AsSG, PbSG, silicon oxynitride (SiON), and SOG (spin-on glass) may
be illustrated; further, a low-permittivity material (e.g. a
poly(aryl ether), a cycloperfluorocarbon polymer, benzocyclobutene,
a cyclic fluorine resin, polytetrafluoroethylene, an aryl ether
fluoride, a polyimide fluoride, amorphous carbon, and an organic
SOG) may be used. As the method for forming the insulating layer,
any of the various PVD methods described above; various CVD
methods; the spin coating method; the various application methods
described above; the sol-gel method; the electrodeposition method;
the shadow mask method; and the spraying method may be given.
Example 1
[0051] Example 1 relates to the imaging element and the electronic
device according to the first embodiment and the second embodiment
of the present disclosure. A schematic partial cross-sectional view
of an imaging element or an electronic device of Example 1 is shown
in FIG. 1B.
[0052] The imaging element or the electronic device of Example 1
(hereinafter, referred to as "the imaging element etc. of Example
1") includes a stacked structure body that is composed of a first
electrode 21, a light receiving layer or a light emitting/light
receiving layer 23 formed on the first electrode 21 (hereinafter,
referred to as "the light receiving layer etc. 23"), and a second
electrode 22 formed on the light receiving layer etc. 23 and on
which light is incident from the second electrode 22. Here, it
should be understood that layer 23 may be a light receiving layer
23 (e.g., of an imaging device), or alternatively, layer 23 may be
a light emitting layer 23 that includes a light source such as a
light-emitting diode (LED). Here, the second electrode 22 is made
of an amorphous oxide (transparent conductive material) made of an
indium-tin oxide in which at least one material selected from the
group consisting of silicon and a silicon oxide is mixed or doped.
Alternatively, the second electrode 22 is made of an amorphous
oxide (transparent conductive material) made of an indium-tin oxide
in which at least one material selected from the group consisting
of cobalt, a cobalt oxide, tungsten, a tungsten oxide, zinc, and a
zinc oxide is mixed or doped. For example, at least one of the
cobalt, the cobalt oxide, the tungsten, the tungsten oxide, the
zin, or the zinc oxide is mixed or doped at 5 mass % or less in the
second electrode. In Example 1, specifically, the second electrode
22 is made of an amorphous oxide made of an indium-tin oxide in
which a silicon oxide is mixed or doped (an ITO-SiO.sub.X-based
material).
[0053] Then, the second electrode 22 has an absorption
characteristic (an ultraviolet absorption characteristic) of 20% or
more and preferably 35% or more at a wavelength of 300 nm, and
further has an absorption characteristic of 15% or more and
preferably 20% or more at a wavelength of 350 nm. Further, the
thickness of the second electrode 22 is 1.times.10.sup.-8 m to
1.5.times.10.sup.-7 m, preferably 2.times.10.sup.-8 m to
1.times.10.sup.-7 m, and more preferably 3.times.10.sup.-8 m to
5.times.10.sup.-8 m; specifically, it is set to 0.05.mu. m in
Example 1.
[0054] Here, in the imaging element etc. of Example 1, more
specifically, the first electrode 21 is formed on a substrate 10
formed of a silicon semiconductor substrate, the light receiving
layer etc. 23 is formed on the first electrode 21, and the second
electrode 22 is formed on the light receiving layer etc. 23. That
is, the electronic device of Example 1 has a two-terminal
electronic device structure including the first electrode 21 and
the second electrode 22. In the light receiving layer etc. 23,
specifically, photoelectric conversion is performed. The second
electrode 22 functions as a cathode electrode (negative electrode).
That is, the second electrode 22 functions as an electrode for
extracting electrons. On the other hand, the first electrode 21
functions as an anode electrode (positive electrode). That is, the
first electrode 21 functions as an electrode for extracting holes.
The light receiving layer etc. 23 is made of an organic
photoelectric conversion material, specifically for example,
quinacridone with a thickness of 0.1 .mu.m. The first electrode 21
and the second electrode 22 are patterned in a desired
configuration. The first electrode 21 may not be patterned
depending on the circumstances, and the second electrode 22 may not
be patterned.
[0055] In the imaging element etc. of Example 1, the light
transmittance of the second electrode 22 for light of wavelengths
of 400 nm to 660 nm is 65% or more, and also the light
transmittance of the first electrode 21 for light of wavelengths of
400 nm to 660 nm is 65% or more. The light transmittance of the
second electrode 22 or the first electrode 21 can be measured by
forming a film of the second electrode 22 or the first electrode 21
on a transparent glass plate. The electric resistance value of the
second electrode 22 is 1.times.10.sup.-6 .OMEGA.cm or less, and the
sheet resistance value of the second electrode 22 is
3.times.10.OMEGA./.quadrature. to
1.times.10.sup.3.OMEGA./.quadrature.. The surface roughness Ra of
the second electrode 22 is 0.5 nm or less, preferably 0.3 nm or
less, and the surface roughness Rq of the second electrode 22 is
0.5 nm or less, preferably 0.3 nm or less.
[0056] A method for manufacturing the imaging element etc. of
Example 1 will now be described with reference to FIG. 1A and FIG.
1B.
[0057] <Process-100>
[0058] A substrate 10 formed of a silicon semiconductor substrate
is prepared. Here, in the substrate 10, for example, a driving
circuit, a light receiving layer, etc. (these not illustrated) of
the imaging element or the electronic device and an interconnection
11 are provided, and an insulating layer 12 is formed on the
surface. In the insulating layer 12, an opening 13 at the bottom of
which the interconnection 11 is exposed is provided. On the
insulating layer 12 including the interior of the opening 13, a
first electrode 21 made of an ITO is formed (as a film) based on
the sputtering method (see FIG. 1A).
[0059] <Process-110>
[0060] Subsequently, the patterning of the first electrode 21 is
performed, then a light receiving layer etc. 23 made of
quinacridone is formed (as a film) on the entire surface by the
vacuum deposition method, further a second electrode 22 made of an
indium-tin oxide in which a silicon oxide (SiO.sub.X) is mixed or
doped (an ITO-SiO.sub.X-based material) is formed (as a film) on
the light receiving layer etc. 23 based on the sputtering method at
room temperature (specifically, 22.degree. C. to 28.degree. C.),
and then the second electrode 22 is patterned based on
photolithography technology and etching technology; thereby, a
second electrode 22 patterned in a desired configuration can be
obtained. Thus, the electronic device of Example 1 having the
structure shown in FIG. 1B can be obtained. A parallel plate
sputtering apparatus or a DC magnetron sputtering apparatus is used
as the sputtering apparatus, argon (Ar) gas is used as the process
gas, and an ITO-SiO.sub.X-based material (assuming that the total
mass of the indium-tin oxide and SiO.sub.X is 100%) is used as the
target. Although in the photolithography technology ultraviolet
light is used for the patterning of the resist material for
etching, the ultraviolet light is absorbed in the second electrode
22, and the arrival of ultraviolet light at the light receiving
layer etc. 23 can be suppressed. A passivation film or the like is
further formed as a film on the entire surface as necessary, and
patterning is performed as necessary. Although also in these
processes ultraviolet light is often used, the ultraviolet light is
absorbed in the second electrode 22 and is less likely to reach the
light receiving layer etc. 23. On-chip microlenses are formed as
necessary; also the ultraviolet light used at this time is absorbed
in the second electrode 22 and is less likely to reach the light
receiving layer etc. 23.
[0061] The film thickness of the second electrode 22 was set to
0.05.mu. m. Further, after the film formation, annealing treatment
at 150.degree. C. for 150 minutes was performed. The relationships
between the SiO.sub.X concentration "X" (mass %), the wavelength of
incident light (.lamda.) the light transmittance (T), and the
absorption characteristic (.alpha.) in cases where the second
electrode 22 is configured from amorphous oxides made of
ITO-SiO.sub.X-based materials (assuming that the total mass of the
indium-tin oxide and SiO.sub.X is 100%) are shown in FIG. 2A and
FIG. 2B, and Table 1. Further, as Comparative Example 1, the
relationships between these in a case where the second electrode 22
is configured from an ITO and an IZO are shown in FIG. 2A and FIG.
2B, and Table 1. Here, the wavelength of incident light .lamda. is
the wavelength of light that passes through the second electrode
22, and .alpha. .sub.300, .alpha. .sub.350, and .alpha. .sub.400
are absorption characteristics at wavelengths of 300 nm, 350 nm,
and 400 nm, respectively. The absorption characteristic of the
second electrode 22 (.alpha., unit: %) is expressed by Formula (1)
below. In addition, "T" represents the light transmittance (unit:
%) of the second electrode 22, and "R" represents the light
reflectance (unit: %) of the second electrode 22. The light
reflectance (R) is the value measured using an absorption
spectrometer.
.alpha.=100-(T+R)(%) (1)
TABLE-US-00001 TABLE 1 Absorption characteristic .alpha. (%) X
(mass %) .alpha..sub.300 .alpha..sub.350 .alpha..sub.400 1 46 16
4.0 2 46 17 4.3 3 44 17 4.3 5 42 19 12 Comparative Example 1 13 3
1.5
[0062] It can be seen from FIG. 2B and Table 1 that, by configuring
the second electrode 22 from an amorphous oxide made of an
ITO-SiO.sub.X-based material, the second electrode 22 exhibits a
high absorption characteristic in an ultraviolet region around 300
nm. Further, in FIG. 2A and FIG. 2B, the data of X=1 mass %, X=2
mass %, and X=3 mass % almost overlap, and the data of X=5 mass %
overlap with the data of X=1 mass %, X=2 mass %, and X=3 mass % in
a fairly large portion; thus, it can be seen that the value of the
SiO.sub.X concentration "X" at the time of forming the second
electrode 22 on the basis of the sputtering method has little
influence on the absorption characteristic .alpha.. In addition, in
FIG. 2A and FIG. 2B, the data of X=5 mass % are shown by "A."
[0063] The imaging element etc. of Example 1A including a second
electrode 22 made of an ITO-SiO.sub.X-based material (provided that
X=2 mass %) and the imaging element of Comparative Example 1
including a second electrode 22 made of an ITO were exposed to a
high temperature, high humidity environment of 85.degree. C. and
85% RH for 500 hours in a state where a reverse bias voltage of 2.6
volts was applied; and it has been found that, for the dark current
in this case on the assumption that the initial dark current value
is 100%, the imaging element etc. of Example 1A exhibited no change
in dark current, whereas Comparative Example 1 exhibited an
increase in dark current of 50%.
[0064] The measurement results of the surface roughnesses Ra and Rq
and the measurement results of the light transmittance of the
second electrodes 22 in the imaging element etc. of Example 1A and
the imaging element of Comparative Example 1 are shown in Table 2.
Further, the measurement results of the surface roughnesses Ra and
Rq of the second electrode 22 in the imaging element etc. of
Example 1B including a second electrode 22 made of an
ITO-SiO.sub.X-based material (provided that X=3 mass %) are shown
in Table 2. Further, a surface SEM image of the second electrode
(provided that it is a product of annealing treatment at
250.degree. C. for 1 hour in a nitrogen atmosphere) in Example 1A
and a surface SEM image of the second electrode (provided that it
is a product of annealing treatment at 250.degree. C. for 1 hour in
a nitrogen atmosphere) in Comparative Example 1 are shown in FIG.
3A and FIG. 3B, respectively. Thus, since the surface of the second
electrode 22 is very smooth, the surface scattering reflection on
the second electrode 22 can be suppressed; consequently, the
surface reflection of light incident on the second electrode 22 can
be reduced, the loss of the amount of light incident on the light
receiving layer etc. 23 via the second electrode 22 can be
suppressed, and the light current characteristics in photoelectric
conversion can be improved still further.
TABLE-US-00002 TABLE 2 Example 1A Example 1B Comparative Example 1
Ra 0.3 nm 0.3 nm 0.8 nm Rq 0.3 nm 0.3 nm 1.0 nm
[0065] Further, the electric resistance value of the second
electrode 22 made of an ITO-SiO.sub.X-based material with a
thickness of 0.05 m in Example 1A was 2.0.times.10.sup.-4
.OMEGA.cm, and the sheet resistance value was
400.OMEGA./.quadrature..
[0066] Further, the value of the internal quantum efficiency and
the value of the ON/OFF ratio of the imaging element etc. of
Example 1A and the imaging element etc. of Comparative Example 1
were as shown in Table 3 below. The internal quantum efficiency
.eta. is the ratio of the number of generated electrons to the
number of incident photons, and can be expressed by the following
formula.
.eta.={(hc)/(q.lamda.)}(I/P)=(1.24/.lamda.)(I/P)
[0067] where
[0068] h: the Planck constant;
[0069] c: the speed of light;
[0070] q: the charge of an electron;
[0071] .lamda.: the wavelength of incident light (.mu. m);
[0072] I: light current, which is, in the measurement of Example 1A
and Comparative Example 1, the current value (amperes/cm.sup.2)
obtained by a reverse bias voltage of 1 volt; and
[0073] P: the power of incident light (amperes/cm.sup.2).
TABLE-US-00003 TABLE 3 Internal quantum efficiency (%) ON/OFF ratio
Example 1A 75 3.9 Comparative Example 1 45 1.6
[0074] Further, the resulting second electrodes were subjected to
an X-ray diffraction test. Charts showing the X-ray diffraction
analysis results of the second electrodes in Example 1 are shown in
FIG. 4. In addition, in each chart of FIG. 4, the uppermost stage
shows the X-ray diffraction analysis results of X=5 mass %, the
second stage shows the X-ray diffraction analysis results of X=3
mass %, the third stage shows the X-ray diffraction analysis
results of X=2 mass %, and the lowermost stage shows the X-ray
diffraction analysis results of X=1 mass %. Further, the oxygen gas
concentration at the time of forming the second electrode by the
sputtering method is varied between charts. Further, a chart
showing the X-ray diffraction analysis result of the second
electrode in Comparative Example 1 is shown in FIG. 5. From FIG. 4,
it can be seen that the second electrode of Example 1 is in an
amorphous state regardless of the film formation condition (oxygen
gas concentration). Then, it can be seen that the amount of oxygen
gas introduced (oxygen gas partial pressure) at the time of forming
the second electrode 22 on the basis of the sputtering method has
little influence on the amorphous state of the second electrode. On
the other hand, from FIG. 5, it can be seen that the second
electrode of Comparative Example 1 has high crystallinity. In view
of FIG. 4, it may be said that at least one of the silicon or the
silicon dioxide is present in the second electrode 22 at a mass %
that allows the second electrode 22 to maintain an amorphous state
regardless of an oxygen gas concentration used to form the second
electrode 22. In view of FIG. 4, it may further be said that the
second electrode 22 has a peak intensity of 2000 or less in X-ray
diffraction.
[0075] It has been found that, in the imaging element etc. of
Example 1A, the stacked structure body has an internal stress of
compressive stress of 10 MPa to 50 MPa. On the other hand, it has
been found that, in the imaging element and the electronic device
of Comparative Example 1, the stacked structure body has a very
high internal stress of compressive stress, i.e. 150 MPa to 180
MPa. In this regard, the first electrode 21, the light receiving
layer etc. 23, and the second electrode 22 were formed as films in
this order on a silicon wafer to form a stacked structure body, and
the internal stress was measured based on a known method using a
commercially available thin film stress measuring apparatus. Each
sample of the stacked structure body that was formed as a film on a
silicon wafer and subjected to stress measurement was immersed in
acetone for 30 seconds, and then the condition of the insulating
layer was observed using an optical microscope (magnification: 5
times). As a result, in Example 1A, there was no change between
before and after immersion; but in Comparative Example 1, peeling
was found in a part between the light receiving layer etc. and the
second electrode. Thus, it has been found that, by forming the
second electrode 22 out of an amorphous oxide, the occurrence of
stress damage in the light receiving layer etc. 23 can be
suppressed reliably during the formation of the second electrode
22.
[0076] Further, a low temperature oxide (LTO, low temperature
CVD-SiO.sub.2) film with a thickness of 0.1 m was formed as a film
on a silicon semiconductor substrate, and the constituent material
of the second electrode (the material in Example 1A) and the
material in Comparative Example 1 (an ITO) were formed as a film on
the LTO film. Then, the amount of warpage of the stacked structure
body composed of the silicon semiconductor substrate, the LTO film,
and the constituent material of the second electrode that, while
the stacked structure body was allowed to stand in the air,
occurred and changed over time due to the LTO film absorbing water
in the air via the constituent material of the second electrode was
measured. As a result, it has been found that the test sample using
the material of Example 1A (an ITO-SiO.sub.X-based material) has a
smaller amount of warpage than the test sample using the material
of Comparative Example 1 (an ITO), and the ITO-SiO.sub.X-based
material film has higher sealability (lower water permeability)
than the ITO film.
[0077] Similar results to those described above were obtained also
in cases where the second electrode 22 was configured from, in
place of an ITO-SiO.sub.X-based material, an ITO-Si-based material,
an ITO-Si--SiO.sub.X-based material, an ITO-Co-based material, an
ITO-CoO.sub.X-based material, an ITO-Co--CoO.sub.X-based material,
an ITO-W-based material, an ITO-WO.sub.X-based material, an
ITO-W--WO.sub.X-based material, an ITO-Zn-based material, an
ITO-ZnO.sub.X-based material, and an ITO-Z--ZnO.sub.X-based
material.
[0078] In the imaging element etc. of Example 1, since the second
electrode is not configured from an ITO but is configured from an
amorphous oxide in which the constituent materials are prescribed,
the internal stress in the second electrode is reduced; thus, an
imaging element, an electronic device, and a solid state imaging
device having high reliability in which, in spite of a simple
configuration and a simple structure, there is no fear that a
characteristic reduction of the imaging element, the electronic
device, or the solid state imaging device will be caused can be
provided. Further, even if a stress buffer layer having a
complicated configuration and a complicated structure is not
formed, stress damage is less likely to occur in the light
receiving layer etc. during the formation of the second electrode.
Further, since the second electrode is configured from an amorphous
oxide, the entry of water can be prevented (or alternatively,
reduced), and an imaging element, an electronic device, and a solid
state imaging device having high reliability can be provided.
Furthermore, the second electrode absorbs ultraviolet light
incident on the second electrode, and consequently the arrival of
ultraviolet light at the light receiving layer etc. can be
suppressed; and since the ultraviolet absorption characteristic of
the second electrode is prescribed, the arrival of ultraviolet
light incident on the second electrode at the light receiving layer
etc. can be suppressed still more reliably. Further, since the
thickness of the second electrode is prescribed, light (light other
than ultraviolet light) can be caused to reach the light receiving
layer etc. via the second electrode still more reliably;
furthermore, the second electrode exhibits a function as an
electrode reliably. Further, since the second electrode is made of
an amorphous oxide having transparency and electrical conductivity,
light incident on the second electrode reaches the light receiving
layer etc. reliably, and holes or electrons generated in the light
receiving layer etc. are reliably sent out to the outside via the
second electrode.
Example 2
[0079] Example 2 relates to the solid state imaging device of an
embodiment of the present disclosure. The solid state imaging
device of Example 2 includes a plurality of imaging elements
(photoelectric conversion elements) each of which is the imaging
element of Example 1.
[0080] A conceptual diagram of a solid state imaging device of
Example 2 is shown in FIG. 6, and the configuration of the solid
state imaging device of Example 2 is shown in FIG. 7. A solid state
imaging device (imaging device) 100 of Example 2 is composed of a
solid state imaging device 40 and known components of a lens group
101, a digital signal processor (DSP) 102, a frame memory 103, a
display device 104, a recording device 105, a manipulation system
106, and a power supply system 107, which components are
electrically connected by a bus line 108. The solid state imaging
device 40 in Example 2 is composed of an imaging region 41 in which
imaging elements 30 described in Example 1 are arranged in a
two-dimensional array configuration on a semiconductor substrate
(e.g. a silicon semiconductor substrate) and, as peripheral
circuits of it, a vertical driving circuit 42, a column signal
processing circuit 43, a horizontal driving circuit 44, an output
circuit 45, a control circuit 46, etc. These circuits may be formed
of known circuits, or may be formed using other circuit
configurations (for example, various circuits used in a CCD imaging
device or a CMOS imaging device in related art), as a matter of
course.
[0081] On the basis of a vertical synchronization signal, a
horizontal synchronization signal, and a master clock, the control
circuit 46 generates a clock signal and a control signal serving as
a basis of the operation of the vertical driving circuit 42, the
column signal processing circuit 43, and the horizontal driving
circuit 44. The generated clock signal and control signal are
inputted to the vertical driving circuit 42, the column signal
processing circuit 43, and the horizontal driving circuit 44.
[0082] The vertical driving circuit 42 is formed of, for example, a
shift register, and selectively scans the imaging elements 30 in
the imaging region 41 sequentially on a row basis in the vertical
direction. A pixel signal based on a current (signal) generated in
accordance with the amount of received light in each imaging
element 30 is sent to the column signal processing circuit 43 via a
vertical signal line 47.
[0083] The column signal processing circuit 43 is placed for each
column of imaging elements 30, for example, and performs the signal
processing of denoising and signal amplification on the signal
outputted from the imaging elements 30 of one row for each imaging
element, based on a signal from a black reference pixel (not
illustrated, formed around the effective pixel area). On the output
stage of the column signal processing circuit 43, a horizontal
select switch (not illustrated) is provided to be connected to a
part leading to a horizontal signal line 48.
[0084] The horizontal driving circuit 44 is formed of, for example,
a shift register; and sequentially outputs horizontal scanning
pulses to sequentially select each of the column signal processing
circuits 43, and outputs the signal from each of the column signal
processing circuits 43 to the horizontal signal line 48.
[0085] The output circuit 45 performs signal processing on the
signal sequentially supplied from each of the column signal
processing circuits 43 via the horizontal signal line 48, and
outputs the resulting signal.
[0086] Depending on the material that forms the light receiving
layer etc., the light receiving layer etc. itself can be configured
to function also as a color filter; therefore, color separation can
be made even without providing a color filter. However, depending
on the circumstances, a known color filter that transmits a
specific wavelength, such as red, green, blue, cyan, magenta, or
yellow, may be provided above the light incidence side of the
imaging element 30. The solid state imaging device may be
configured as a front-side illumination type, or may be configured
as a back-side illumination type. As necessary, a shutter for
controlling the incidence of light on the imaging element 30 may be
provided.
[0087] Hereinabove, embodiments of the present disclosure are
described based on preferred Examples, but the present disclosure
is not limited to these Examples. The structure, configuration,
manufacturing conditions, manufacturing method, and used material
of the imaging element, the electronic device, and the solid state
imaging device described in Examples are only examples, and may be
altered as appropriate. In the case where the electronic device of
an embodiment of the present disclosure is made to function as a
solar cell, the light receiving layer etc. may be irradiated with
light in a state where a voltage is not applied between the second
electrode and the first electrode. Also a light sensor and an image
sensor can be formed by using the electronic device of an
embodiment of the present disclosure. The first electrode may be
formed of an amorphous oxide made of an indium-tin oxide in which
at least one material selected from the group consisting of
silicon, a silicon oxide, cobalt, a cobalt oxide, tungsten, a
tungsten oxide, zinc, and a zinc oxide is mixed or doped.
[0088] Further, the composition of the second electrode included in
the imaging element of an embodiment of the present disclosure may
be used for various fields in which transparency and electrical
conductivity are required. That is, a transparent conductive
material made of an amorphous oxide made of an indium-tin oxide in
which at least one material selected from the group consisting of
silicon, a silicon oxide, cobalt, a cobalt oxide, tungsten, a
tungsten oxide, zinc, and a zinc oxide is mixed or doped (for
example, an ITO-Si-based material, an ITO-SiO.sub.X-based material,
an ITO-Si--SiO.sub.X-based material, an ITO-Co-based material, an
ITO-CoO.sub.X-based material, an ITO-Co--CoO.sub.X-based material,
an ITO-W-based material, an ITO-WO.sub.X-based material, an
ITO-W--WO.sub.X-based material, an ITO-Zn-based material, an
ITO-ZnO.sub.X-based material, and an ITO-Z--ZnO.sub.X-based
material) may be used in various fields. The various prescriptions
related to the second electrode in the imaging element of an
embodiment of the present disclosure may be used for this
transparent conductive material.
[0089] Additionally, the present technology may also be configured
as below.
[0090] (A01) <<Imaging Element: First Embodiment>>
[0091] An imaging element including:
[0092] a stacked structure body composed of
[0093] a first electrode,
[0094] a light receiving layer formed on the first electrode,
and
[0095] a second electrode formed on the light receiving layer,
[0096] and configured such that light is incident from the second
electrode, in which the second electrode is made of an amorphous
oxide made of an indium-tin oxide in which at least one material
selected from the group consisting of silicon and a silicon oxide
is mixed or doped.
[0097] (A02)
[0098] The imaging element according to (A01), in which the second
electrode has absorption characteristics of 20% or more at a
wavelength of 300 nm and 15% or more at a wavelength of 350 nm.
[0099] (A03)
[0100] The imaging element according to (A01) or (A02), in which a
thickness of the second electrode is 1.times.10.sup.-8 m to
1.5.times.10.sup.-7 m.
[0101] (A04)
[0102] The imaging element according to any one of (A01) to (A03),
in which the material is mixed or doped at 5 mass % or less in the
second electrode.
[0103] (A05)
[0104] The imaging element according to (A04), in which the
material is mixed or doped at 1 mass % or more and 3 mass % or less
in the second electrode.
[0105] (A06)
[0106] The imaging element according to any one of (A01) to (A05),
in which a surface roughness Ra of the second electrode is 0.5 nm
or less, and a surface roughness Rq of the second electrode is 0.5
nm or less.
[0107] (A07)
[0108] The imaging element according to any one of (A01) to (A06),
in which a light transmittance of the second electrode for light of
wavelengths of 400 nm to 660 nm is 65% or more.
[0109] (A08)
[0110] The imaging element according to any one of (A01) to (A07),
in which an electric resistance value of the second electrode is
1.times.10.sup.6 .OMEGA.cm or less.
[0111] (A09)
[0112] The imaging element according to any one of (A01) to (A07),
in which a sheet resistance value of the second electrode is
3.times.10.OMEGA./.quadrature. to
1.times.10.sup.3.OMEGA./.quadrature..
[0113] (A10)
[0114] The imaging element according to any one of (A01) to (A09),
in which the stacked structure body has an internal stress of
compressive stress of 10 MPa to 50 MPa.
[0115] (A11)
[0116] The imaging element according to any one of (A01) to (A10),
in which the first electrode is made of an amorphous oxide made of
an indium-tin oxide in which at least one material selected from
the group consisting of silicon, a silicon oxide, cobalt, a cobalt
oxide, tungsten, a tungsten oxide, zinc, and a zinc oxide is mixed
or doped.
[0117] (B01)<<Imaging Element: Second Embodiment>>
[0118] An imaging element including:
[0119] a stacked structure body composed of
[0120] a first electrode,
[0121] a light receiving layer formed on the first electrode,
and
[0122] a second electrode formed on the light receiving layer,
[0123] and configured such that light is incident from the second
electrode, in which the second electrode is made of an amorphous
oxide made of an indium-tin oxide in which at least one material
selected from the group consisting of cobalt, a cobalt oxide,
tungsten, a tungsten oxide, zinc, and a zinc oxide is mixed or
doped.
[0124] (B02)
[0125] The imaging element according to (B01), in which the second
electrode has absorption characteristics of 20% or more at a
wavelength of 300 nm and 15% or more at a wavelength of 350 nm.
[0126] (B03)
[0127] The imaging element according to (B01) or (B02), in which a
thickness of the second electrode is 1.times.10.sup.-8 m to
1.5.times.10.sup.-7 m.
[0128] (B04)
[0129] The imaging element according to any one of (B01) to (B03),
in which the material is mixed or doped at 5 mass % or less in the
second electrode.
[0130] (B05)
[0131] The imaging element according to (B04), in which the
material is mixed or doped at 1 mass % or more and 3 mass % or less
in the second electrode.
[0132] (B06)
[0133] The imaging element according to any one of (B01) to (B05),
in which a surface roughness Ra of the second electrode is 0.5 nm
or less, and a surface roughness Rq of the second electrode is 0.5
nm or less.
[0134] (B07)
[0135] The imaging element according to any one of (B01) to (B06),
in which a light transmittance of the second electrode for light of
wavelengths of 400 nm to 660 nm is 65% or more.
[0136] (B08)
[0137] The imaging element according to any one of (B01) to (B07),
in which an electric resistance value of the second electrode is
1.times.10.sup.6 .OMEGA.cm or less.
[0138] (B09)
[0139] The imaging element according to any one of (B01) to (B07),
in which a sheet resistance value of the second electrode is
3.times.10.OMEGA./.quadrature. to
1.times.10.sup.3.OMEGA./.quadrature..
[0140] (B10)
[0141] The imaging element according to any one of (B01) to (B09),
in which the stacked structure body has an internal stress of
compressive stress of 10 MPa to 50 MPa.
[0142] (B11)
[0143] The imaging element according to any one of (B01) to (B10),
in which the first electrode is made of an amorphous oxide made of
an indium-tin oxide in which at least one material selected from
the group consisting of silicon, a silicon oxide, cobalt, a cobalt
oxide, tungsten, a tungsten oxide, zinc, and a zinc oxide is mixed
or doped.
[0144] (C01)<<Solid State Imaging Device: First
Embodiment>>
[0145] A solid state imaging device including a plurality of
imaging elements,
[0146] in which each of the imaging elements includes
[0147] a stacked structure body composed of
[0148] a first electrode,
[0149] a light receiving layer formed on the first electrode,
and
[0150] a second electrode formed on the light receiving layer,
[0151] and configured such that light is incident from the second
electrode, and
[0152] the second electrode is made of an amorphous oxide made of
an indium-tin oxide in which at least one material selected from
the group consisting of silicon and a silicon oxide is mixed or
doped.
[0153] (C02)
[0154] A solid state imaging device including a plurality of
imaging elements each of which is the imaging element according to
any one of (A01) to (A11).
[0155] (C03)<<Solid State Imaging Device: Second
Embodiment>>
[0156] A solid state imaging device including a plurality of
imaging elements,
[0157] in which each of the imaging elements includes
[0158] a stacked structure body composed of
[0159] a first electrode,
[0160] a light receiving layer formed on the first electrode,
and
[0161] a second electrode formed on the light receiving layer,
[0162] and configured such that light is incident from the second
electrode, and
[0163] the second electrode is made of an amorphous oxide made of
an indium-tin oxide in which at least one material selected from
the group consisting of cobalt, a cobalt oxide, tungsten, a
tungsten oxide, zinc, and a zinc oxide is mixed or doped.
[0164] (C04)
[0165] A solid state imaging device including a plurality of
imaging elements each of which is the imaging element according to
any one of (B01) to (B11).
[0166] (D01)<<Electronic Device: First Embodiment>>
[0167] An electronic device including:
[0168] a stacked structure body composed of
[0169] a first electrode,
[0170] a light emitting/light receiving layer formed on the first
electrode, and
[0171] a second electrode formed on the light emitting/light
receiving layer,
[0172] and configured such that light is incident from the second
electrode, in which the second electrode is made of an amorphous
oxide made of an indium-tin oxide in which at least one material
selected from the group consisting of silicon and a silicon oxide
is mixed or doped.
[0173] (D02)
[0174] The electronic device according to (D01), in which the
second electrode has absorption characteristics of 20% or more at a
wavelength of 300 nm and 15% or more at a wavelength of 350 nm.
[0175] (D03)
[0176] The electronic device according to (D01) or (D02), in which
a thickness of the second electrode is 1.times.10.sup.-8 m to
1.5.times.10.sup.-7 m.
[0177] (D04)
The electronic device according to any one of (D01) to (D03), in
which the material is mixed or doped at 5 mass % or less in the
second electrode.
[0178] (D05)
[0179] The electronic device according to (D04), in which the
material is mixed or doped at 1 mass % or more and 3 mass % or less
in the second electrode.
[0180] (D06)
[0181] The electronic device according to any one of (D01) to
(D05), in which a surface roughness Ra of the second electrode is
0.5 nm or less, and a surface roughness Rq of the second electrode
is 0.5 nm or less.
[0182] (D07)
[0183] The electronic device according to any one of (D01) to
(D06), in which a light transmittance of the second electrode for
light of wavelengths of 400 nm to 660 nm is 65% or more.
[0184] (D08)
[0185] The electronic device according to any one of (D01) to
(D07), in which an electric resistance value of the second
electrode is 1.times.10.sup.-6 .OMEGA.cm or less.
[0186] (D09)
[0187] The electronic device according to any one of (D01) to
(D07), in which a sheet resistance value of the second electrode is
3.times.10.OMEGA./.quadrature. to
1.times.10.sup.3.OMEGA./.quadrature..
[0188] (D10)
[0189] The electronic device according to any one of (D01) to
(D09), in which the stacked structure body has an internal stress
of compressive stress of 10 MPa to 50 MPa.
[0190] (D11)
[0191] The electronic device according to any one of (D01) to
(D10), in which the first electrode is made of an amorphous oxide
made of an indium-tin oxide in which at least one material selected
from the group consisting of silicon, a silicon oxide, cobalt, a
cobalt oxide, tungsten, a tungsten oxide, zinc, and a zinc oxide is
mixed or doped.
[0192] (E01)<<Electronic Device: Second
Embodiment>>
[0193] An electronic device including:
[0194] a stacked structure body composed of
[0195] a first electrode,
[0196] a light emitting/light receiving layer formed on the first
electrode, and
[0197] a second electrode formed on the light emitting/light
receiving layer,
[0198] and configured such that light is incident from the second
electrode, in which the second electrode is made of an amorphous
oxide made of an indium-tin oxide in which at least one material
selected from the group consisting of cobalt, a cobalt oxide,
tungsten, a tungsten oxide, zinc, and a zinc oxide is mixed or
doped.
[0199] (E02)
[0200] The electronic device according to (E01), in which the
second electrode has absorption characteristics of 20% or more at a
wavelength of 300 nm and 15% or more at a wavelength of 350 nm.
[0201] (E03)
[0202] The electronic device according to (E01) or (E02), in which
a thickness of the second electrode is 1.times.10.sup.-8 m to
1.5.times.10.sup.-7 m.
[0203] (E04)
[0204] The electronic device according to any one of (E01) to
(E03), in which the material is mixed or doped at 5 mass % or less
in the second electrode.
[0205] (E05)
[0206] The electronic device according to (E04), in which the
material is mixed or doped at 1 mass % or more and 3 mass % or less
in the second electrode.
[0207] (E06)
[0208] The electronic device according to any one of (E01) to
(E05), in which a surface roughness Ra of the second electrode is
0.5 nm or less, and a surface roughness Rq of the second electrode
is 0.5 nm or less.
[0209] (E07)
[0210] The electronic device according to any one of (E01) to
(E06), in which a light transmittance of the second electrode for
light of wavelengths of 400 nm to 660 nm is 65% or more.
[0211] (E08)
[0212] The electronic device according to any one of (E01) to
(E07), in which an electric resistance value of the second
electrode is 1.times.10.sup.-6 .OMEGA.cm or less.
[0213] (E09)
[0214] The electronic device according to any one of (E01) to
(E07), in which a sheet resistance value of the second electrode is
3.times.10.OMEGA./.quadrature. to
1.times.10.sup.3.OMEGA./.quadrature..
[0215] (E10)
[0216] The electronic device according to any one of (E01) to
(E09), in which the stacked structure body has an internal stress
of compressive stress of 10 MPa to 50 MPa.
[0217] (E11)
[0218] The electronic device according to any one of (E01) to
(E10), in which the first electrode is made of an amorphous oxide
made of an indium-tin oxide in which at least one material selected
from the group consisting of silicon, a silicon oxide, cobalt, a
cobalt oxide, tungsten, a tungsten oxide, zinc, and a zinc oxide is
mixed or doped.
[0219] (1)
[0220] An imaging element, comprising: [0221] a first electrode;
[0222] a second electrode; and [0223] a light receiving layer
between the first electrode and the second electrode to receive
incident light from the second electrode, [0224] wherein the second
electrode includes an indium-tin oxide layer which includes at
least one of silicon or silicon oxide.
[0225] (2)
[0226] The imaging element of (1), wherein the second electrode is
amorphous.
[0227] (3)
[0228] The imaging element according to (1), wherein the second
electrode has absorption characteristics of 20% or more at a
wavelength of 300 nm.
[0229] (4)
[0230] The imaging element according to (1), wherein a thickness of
the second electrode is 1.times.10.sup.-8 m to 1.5.times.10.sup.-7
m.
[0231] (5)
[0232] The imaging element according to (1), wherein the at least
one of the silicon or the silicon dioxide is mixed or doped at 5
mass % or less in the second electrode.
[0233] (6)
[0234] The imaging element according to (1), wherein the at least
one of the silicon or the silicon dioxide is mixed or doped at 1
mass % or more and 3 mass % or less in the second electrode.
[0235] (7)
[0236] The imaging element according to (1), wherein a surface
roughness Ra of the second electrode is 0.5 nm or less, and a
surface roughness Rq of the second electrode is 0.5 nm or less.
[0237] (8)
[0238] The imaging element according to (1), wherein a light
transmittance of the second electrode for light of wavelengths of
400 nm to 660 nm is 65% or more.
[0239] (9)
[0240] The imaging element according to (1), wherein an electric
resistance value of the second electrode is 1.times.10.sup.6
.OMEGA.cm or less.
[0241] (10)
[0242] The imaging element according to (1), wherein the first
electrode includes an indium-tin oxide layer which includes at
least one of silicon, silicon oxide, cobalt, cobalt oxide,
tungsten, tungsten oxide, zinc, or zinc oxide.
[0243] (11)
[0244] The imaging element according to (10), wherein the first
electrode is amorphous.
[0245] (12)
[0246] The imaging element according to (10), wherein the at least
one of the silicon, the silicon oxide, the cobalt, the cobalt
oxide, the tungsten, the tungsten oxide, the zinc, or the zinc
oxide is mixed or doped in the first electrode.
[0247] (13)
[0248] The imaging element according to (1), wherein the second
electrode has absorption characteristics of 15% or more at a
wavelength of 350 nm.
[0249] (14)
[0250] The imaging element according to (1), wherein the second
electrode has a peak intensity of 2000 or less in X-ray
diffraction.
[0251] (15)
[0252] A solid state imaging device, comprising: [0253] a plurality
of imaging elements each having a structure of the imaging element
according to (1).
[0254] (16)
[0255] An imaging element, comprising: [0256] a first electrode;
[0257] a second electrode; and [0258] a light receiving layer
between the first electrode and the second electrode to receive
incident light from the second electrode, [0259] wherein the second
electrode includes an indium-tin oxide layer which includes at
least one of cobalt, cobalt oxide, tungsten, tungsten oxide, zinc,
or zinc oxide.
[0260] (17)
[0261] The imaging element according to (16), wherein the second
electrode is amorphous.
[0262] (18)
[0263] The imaging element according to (16), wherein the at least
one of the cobalt, the cobalt oxide, the tungsten, the tungsten
oxide, the zin, or the zinc oxide is mixed or doped at 5 mass % or
less in the second electrode.
[0264] (19)
[0265] A solid state imaging device, comprising: [0266] a plurality
of imaging elements each having a structure of the imaging element
according to (16).
[0267] (20)
[0268] An electronic device, comprising: [0269] a first electrode;
[0270] a second electrode; and [0271] a light emitting or receiving
layer between the first electrode and the second electrode to
transmit light received from the second electrode, [0272] wherein
the second electrode includes an indium-tin oxide layer which
includes i) at least one of silicon or silicon oxide, or ii) at
least one of cobalt, cobalt oxide, tungsten, tungsten oxide, zinc,
or zinc oxide.
REFERENCE SIGNS LIST
[0272] [0273] 10 substrate [0274] 11 interconnection [0275] 12
insulating layer [0276] 13 opening [0277] 21 first electrode [0278]
22 second electrode [0279] 23 light receiving layer or light
emitting/light receiving layer (light receiving layer etc.) [0280]
30 imaging element [0281] 40 solid state imaging device [0282] 41
imaging region [0283] 42 vertical driving circuit [0284] 43 column
signal processing circuit [0285] 44 horizontal driving circuit
[0286] 45 output circuit [0287] 46 control circuit [0288] 47
vertical signal line [0289] 48 horizontal signal line [0290] 101
lens group [0291] 102 digital signal processor (DSP) [0292] 103
frame memory [0293] 104 display device [0294] 105 recording device
[0295] 106 manipulation system [0296] 107 power supply system
[0297] 108 bus line
* * * * *