U.S. patent application number 13/605982 was filed with the patent office on 2013-06-20 for three-dimensional non-volatile memory device, memory system and method of manufacturing the same.
The applicant listed for this patent is Young Soo Ahn, Jong Moo Choi, Yoo Hyun NOH. Invention is credited to Young Soo Ahn, Jong Moo Choi, Yoo Hyun NOH.
Application Number | 20130153979 13/605982 |
Document ID | / |
Family ID | 48588566 |
Filed Date | 2013-06-20 |
United States Patent
Application |
20130153979 |
Kind Code |
A1 |
NOH; Yoo Hyun ; et
al. |
June 20, 2013 |
THREE-DIMENSIONAL NON-VOLATILE MEMORY DEVICE, MEMORY SYSTEM AND
METHOD OF MANUFACTURING THE SAME
Abstract
A three-dimensional (3-D) non-volatile memory device includes
channel structures each including channel layers stacked over a
substrate and extending in a first direction, wherein the channel
layers include well regions, respectively, vertical gates located
and spaced from each other between the channel structures, and a
well pick-up line contacting on the well regions of the channel
layers and extending in a second direction crossing the channel
structures.
Inventors: |
NOH; Yoo Hyun; (Seoul,
KR) ; Choi; Jong Moo; (Chungcheongbuk-do, KR)
; Ahn; Young Soo; (Gyeonggi-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NOH; Yoo Hyun
Choi; Jong Moo
Ahn; Young Soo |
Seoul
Chungcheongbuk-do
Gyeonggi-do |
|
KR
KR
KR |
|
|
Family ID: |
48588566 |
Appl. No.: |
13/605982 |
Filed: |
September 6, 2012 |
Current U.S.
Class: |
257/314 ;
257/E21.411; 257/E29.262; 438/268 |
Current CPC
Class: |
H01L 27/11578 20130101;
H01L 21/266 20130101; H01L 27/11582 20130101 |
Class at
Publication: |
257/314 ;
438/268; 257/E29.262; 257/E21.411 |
International
Class: |
H01L 29/78 20060101
H01L029/78; H01L 21/336 20060101 H01L021/336 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 19, 2011 |
KR |
10-2011-0137331 |
Claims
1. A three-dimensional (3-D) non-volatile memory device,
comprising: channel structures each including channel layers
stacked over a substrate and extending in a first direction,
wherein the channel layers include well regions, respectively;
vertical gates located and spaced from each other between the
channel structures; and a well pickup line contacting on the well
regions of the channel layers and extending in a second direction
crossing the channel structures.
2. The 3-D non-volatile memory device of claim 1, further
comprising: word lines coupled to the vertical gates and extending
in the second direction crossing the channel structures; and a
memory layer interposed between the channel structures and the
vertical gates, and between the channel structures and each of the
word lines.
3. The 3-D non-volatile memory device of claim 1, further
comprising junctions formed in the channel layers exposed between
the vertical gates.
4. The 3-D non-volatile memory device of claim 3, wherein the
channel layers include P type impurities at a low concentration,
the junctions include N type impurities and the well regions
include the P type impurities at a high concentration.
5. The 3-D non-volatile memory device of claim 1, further
comprising: source regions formed in each of the channel layers;
and a source line contacting on the source regions of the channel
layers and extending in the second direction crossing the channel
structures.
6. The 3-D non-volatile memory device of claim 5, wherein the
channel layers include P type impurities at a low concentration,
the source regions include N type impurities and the well regions
include the P type impurities at a high concentration.
7. A memory system, comprising: a three-dimensional (3-D)
non-volatile memory device including channel structures each having
channel layers that are stacked over a substrate and includes
respective well regions, vertical gates located and spaced from
each other between the channel structures, and a well pickup line
contacting on the well regions of the channel layers and extending
in a direction crossing the channel structures; and a memory
controller configured to control the 3-D non-volatile memory
device.
8. The memory system of claim 7, further comprising junctions
formed in the channel layers exposed between the vertical
gates.
9. The memory system of claim 7, further comprising: source regions
formed in each of the channel layers; and a source line contacting
on the source regions of the channel layers and extending in the
direction crossing the channel structures.
10. A method of manufacturing a three-dimensional (3-D)
non-volatile memory device, the method comprising: forming channel
structures each including channel layers and interlayer insulating
layers stacked alternately over a substrate, wherein the channel
layers include well regions, respectively; forming vertical gates
spaced from each other between the channel structures; and forming
a well pickup line contacting on the well regions of the channel
layers and extending in a direction crossing the channel
structures.
11. The method of claim 10, wherein the forming of the channel
structures comprises: alternately forming the interlayer insulating
layers and the channel layers over the substrate; and etching the
interlayer insulating layers and the channel layers to form the
channel structures extending in parallel along one direction.
12. The method of claim 11, wherein the forming of the interlayer
insulating layers and the channel layers comprises: doping a
portion of each of the channel layers with impurities to form a
well region after forming the each of the channel layers.
13. The method of claim 11, wherein the forming of the channel
structures further comprises: forming a mask pattern exposing
portions of the channel structures corresponding to the well
regions of the channel layers; and forming the well regions in the
channel layers by doping the channel layers with impurities by
using the mask pattern as a barrier.
14. The method of claim 10, wherein the forming of the vertical
gates comprises: forming a memory layer over an entire surface of
the channel structures; forming a conductive layer on the memory
layer; and forming the vertical gates and word lines coupled to the
vertical gates by etching the conductive layer and the memory
layer, wherein the word lines extend in the direction crossing the
channel structures.
15. The method of claim 10, further comprising: forming a mask
pattern covering the well regions of the channel layers after the
forming of the vertical gates; and forming junctions in each of the
channel layers between the vertical gates and source regions in
portions of the channel layers by doping the channel layers exposed
between the mask pattern and the vertical gates with
impurities.
16. The method of claim 15, wherein the forming of the junctions
and the source regions is performed by using a tilting ion
implantation process or a plasma doping process.
17. The method of claim 15, further comprising forming a source
line coupled to the source regions of the channel layers and
extending in the direction crossing the channel structures.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Priority is claimed to Korean patent application number
10-2011-0137331 filed on Dec. 19, 2011, the entire disclosure of
which is incorporated herein by reference in its entirety.
BACKGROUND
[0002] 1. Field of Invention
[0003] Embodiments of the present invention relate to a
semiconductor device, a memory system and a method of manufacturing
the same and, more particularly, to a three-dimensional
non-volatile memory device, and a memory system and a manufacturing
method of the same.
[0004] 2. Description of Related Art
[0005] A non-volatile memory device retains data even in the
absence of power supply. Two-dimensional memory devices in which
memory cells are fabricated in a single layer over a silicon
substrate have reaches physical limits in increasing their degree
of integration. Accordingly, three-dimensional non-volatile memory
devices in which memory cells are stacked in a vertical direction
over a silicon substrate have been proposed.
[0006] Hereinafter, the structure of a three-dimensional (3-D)
non-volatile memory device is described with reference to FIG.
1.
[0007] FIG. 1 is a perspective view illustrating the structure of a
conventional 3-D non-volatile memory device.
[0008] As shown in FIG. 1, the conventional 3-D non-volatile memory
device may include channel structures C, vertical gates 14 and word
lines WL. The channel structures C may extend in parallel along a
first direction I-I'. The vertical gates 14 may be located between
adjacent channel structures C and protrude from the substrate 10.
The word lines WL may be coupled to the vertical gates 14 and
extend in parallel along a second direction II-II'.
[0009] Here, each of the channel structures C may include
interlayer insulating layers 11 and channel layers 12 that are
alternately stacked over the substrate 10. In addition, a tunnel
insulating layer 13A, a charge trap layer 13B and a charge blocking
layer 13C may be interposed between the vertical gates 14 and the
channel structures C.
[0010] According to the above-described structure, a string may be
arranged in a horizontal direction against the substrate 10. These
strings may be stacked over the substrate 10. Therefore, as
compared to a two-dimensional structure memory device, an
integration degree of the 3-D memory device having the above
structure may be increased. However, because a well region is not
provided in a 3-D memory device, the 3-D memory device may have a
low operating speed.
BRIEF SUMMARY
[0011] An embodiment of the present invention relates to a
three-dimensional non-volatile memory device with improved
operating speed, and a memory system and a manufacturing method of
the same.
[0012] A three-dimensional (3-D) non-volatile memory device
according to an embodiment of the present invention includes
channel structures each including channel layers stacked over a
substrate and extending in a first direction, wherein the channel
layers include well regions, respectively, vertical gates located
and spaced from each other between the channel structures, and a
well pickup line contacting on the well regions of the channel
layers and extending in a second direction crossing the channel
structures.
[0013] A memory system according to another embodiment of the
present invention includes a three-dimensional (3-D) non-volatile
memory device including channel structures each having channel
layers that are stacked over a substrate and includes respective
well regions, vertical gates located and spaced from each other
between the channel structures, and a well pickup line contacting
on the well regions the channel layers and extending in a direction
crossing the channel structures, and a memory controller configured
to control the 3-D non-volatile memory device.
[0014] A method of manufacturing a three-dimensional (3-D)
non-volatile memory device according to yet another embodiment of
the present invention includes forming channel structures each
including channel layers and interlayer insulating layers stacked
alternately over a substrate, wherein the channel layers include
well regions, respectively, forming vertical gates spaced from each
other between the channel structures, and a well pickup line
contacting on the well regions of the channel layers and extending
in a direction crossing the channel structures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a perspective view illustrating the structure of a
conventional three-dimensional (3-D) non-volatile memory
device;
[0016] FIGS. 2A to 5B are views illustrating a method of
manufacturing a 3-D non-volatile memory device according to an
embodiment of the present invention;
[0017] FIG. 6 is a block diagram illustrating a memory system
according to an embodiment of the present invention; and
[0018] FIG. 7 is a block diagram illustrating a computing system
according to an embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0019] Hereinafter, various embodiments of the present invention
will be described in detail with reference to the accompanying
drawings. The figures are provided to enable those of ordinary
skill in the art to make and use the present invention according to
the embodiments of the present invention.
[0020] FIGS. 2A to 5B are views illustrating a method of
manufacturing a three-dimensional (3-D) non-volatile memory device
according to an embodiment of the present invention. FIGS. 2A to 5A
are perspective views. FIGS. 2B to 4B are plan views taken along
line A-A' of FIGS. 2A to 4A, respectively, and FIG. 5B is a top
plan view of FIG. 5A.
[0021] As illustrated in FIGS. 2A and 2B, an interlayer insulating
layer 21 and a channel layer 22 may be formed over a substrate 20.
Here, the interlayer insulating layer 21 may comprise an oxide
layer. The channel layer 22 may comprise a semiconductor layer such
as a polysilicon layer, or a polysilicon layer doped with P type
impurities at a low concentration.
[0022] According to an embodiment of the present invention, channel
structures C may be formed in subsequent processes. The channel
structures C may include channel layers stacked over the substrate
20. Memory cells MC may be formed along sidewalls of the channel
structures C. In addition, each of the channel layers may be doped
with impurities to form a well region W and a source region S. For
example, the well region W may be located at one end of each of the
channel layers included in the channel structure C. The source
region S may be located between the well region W and a region MC
in which memory cells are formed. In FIG. 2B, positions of
corresponding regions are indicated by dotted lines for
illustration purposes.
[0023] A portion of the channel layer 22 may be doped with
impurities to form the well region W. For example, a mask pattern
(not shown) that exposes the portion of the channel layer 22 may be
formed over the channel layer 22. Subsequently, the channel layer
22 may be doped with impurities by using the mask pattern as a
barrier to thus form the well region W. The mask pattern may expose
a portion of the channel layer 22 in which the well region W is
formed, while the mask pattern may cover other portions of the
channel layer 22 in which the source region S and the memory cells
MC are formed. The channel layer 22 may be doped with impurities by
using an ion implantation process or a plasma doping process. For
example, the channel layer 22 may be doped with P-type impurities
such as Boron (B). In this case, a P type well region W having a
high impurity concentration may be defined in a P type channel
having a low impurity concentration. More specifically, the well
region W may include the same type of impurities as the channel
layer 22, and the well region W may have a higher impurity
concentration than the channel layer 22.
[0024] As illustrated in FIGS. 3A and 3B, the processes of forming
the interlayer insulating layer 21, the channel layer 22 and the
well region W may be repeated a number of times. In other words,
the interlayer insulating layers 21 and the channel layers 22 may
be alternately formed. Each time the channel layer 22 is formed, a
portion of the channel layer 22 may be doped with impurities to
form the well region W.
[0025] After the interlayer insulating layers 21 and the channel
layers 22 are alternately formed by the number of strings to be
stacked, the interlayer insulating layers 21 and the channel layers
22 that are alternately stacked may be etched to form the channel
structures C. The channel structures C may extend in parallel along
one direction. Therefore, the channel structures C may include
channel layers 22A that are stacked over the substrate 20. Each of
the channel layers 22A may include the well region W. Here,
interlayer insulating layers 21A may be interposed between the
channel layers 22A that are stacked.
[0026] For reference, after the channel structures C are formed,
the well regions W of the channel layers 22A may be formed at the
same time. For example, after the interlayer insulating layers 21
and the channel layers 22 may be alternately formed and
subsequently etched to form the channel structures C, a mask
pattern that exposes the well regions W may be formed.
Subsequently, exposed regions of the channel layers 22A may be
doped with impurities by using a tilting ion implantation process
or a plasma doping process by using a mask pattern as a barrier. In
this manner, the well regions W of the channel layers 22A stacked
upon one another may be formed at the same time.
[0027] Here, since the well regions W are formed by doping the
channel layers 22A exposed on sidewalls of the channel structures C
with impurities, conditions of an impurity doping process may be
controlled so that the center area of the channel layers 22 may be
doped sufficiently.
[0028] As illustrated in FIGS. 4A and 4B, memory layers 23 may be
formed. Each of the memory layers 23 may be formed over an entire
surface of a resultant structure including the channel structures
C. The memory layer 23 may be formed to store data by
injecting/discharging charges. For example, the memory layer 23 may
include a tunnel insulating layer, a charge trap layer and a charge
blocking layer.
[0029] Subsequently, conductive layers 24 may be formed on the
memory layers 23. The conductive layer 24 may have such a thickness
that the conductive layer 24 may be filled between the channel
structures C and may be formed on the top of the channel structures
C. Subsequently, a mask pattern (not shown) in the form of lines
that extend in parallel along a direction crossing the channel
structures C may be formed over the conductive layer 24.
Subsequently, the conductive layer 24 and the memory layer 23 may
be etched by using the mask pattern as a barrier.
[0030] As a result, vertical gates and word lines WL may be formed.
The vertical gates may be located between the channel structures C.
The word lines WL may couple the vertical gates and extend in a
direction crossing the channel structures C. Here, the memory
layers 23 may be interposed between the word lines WL and the
channel structures C. The memory cells MC may be formed along the
sidewalls of the channel structures C.
[0031] Subsequently, a mask pattern 25 used to form a junction and
a source region may be formed over a resultant structure having the
word lines WL. For example, the mask pattern 25 may be a
photoresist pattern. The mask pattern 25 may prevent the well
regions W from being doped with impurities in subsequent impurity
doping processes. The mask pattern 25 may have a large area enough
to completely cover the well regions W. In addition, the mask
pattern 25 may completely expose the source regions S and the
region MC in which the memory cells MC are formed.
[0032] Subsequently, the channel layers 22A exposed between the
mask pattern 25 and the word lines WL may be doped with impurities.
For example, the channel layers 22A may be doped with N type
impurities such as phosphorous (P) or phosphorous (As). In this
case, N type junctions 26 and N type source regions S may be formed
in P type channel layers 22A.
[0033] Here, sidewalls of the channel layers 22A exposed on both
sidewalls of the channel structures C may be doped with impurities
to form the junctions 26 and the source regions S. Here, the
junctions 26 may be formed in each of the channel layers 22A
exposed between the vertical gates 24. The source regions S may be
formed on portions of the channel layers 22A. For example, each of
the source regions S may be formed between the word lines WL and
the well region W.
[0034] The sidewalls of the channel layers 22A may be doped with
impurities by using a plasma doping process or a tilting ion
implantation process in which ions are implanted while tilting the
substrate. Here, the channel layers 22A may be doped with
impurities from surfaces of both sidewalls thereof to a given
depth. Conditions of an impurity doping process may be controlled
to separate the junctions 26, the source regions S and the well
regions W from each other.
[0035] As illustrated in FIGS. 5A and 5B, after the mask pattern 25
is removed, an interlayer insulating layer (not illustrated) may be
formed over a resultant structure having the junctions 26. Here,
the interlayer insulating layer may comprise an oxide layer.
[0036] Subsequently, the interlayer insulating layer may be etched
to form a source line trench that exposes the source regions S of
the channel structures C and a well pickup line trench that exposes
the well regions W of the channel structures C. Subsequently, the
source line trench and the well pickup line trench may be filled
with conductive layers. Therefore, a source line SL and a well
pickup line Well_PL may be formed. The source line SL may extend in
the direction crossing the channel structures C and contact on the
source regions S of the channel layers 22A. The well pickup line
Well_PL may contact on the well regions W of the channel layers
22A.
[0037] Here, the source line SL and the well pickup line Well_PL
may have structures substantially similar to the word line WL. The
source line SL and the well pickup line Well_PL each may have
vertical gate portions located between the channel structures C and
line portions coupling the vertical gate portions.
[0038] A three-dimensional (3-D) non-volatile memory device
according to an embodiment of the present invention may be
manufactured by performing the aforementioned processes. The 3-D
non-volatile memory device may include the channel structures C,
the vertical gates 24, the junctions 26, the source line SL and the
well pickup line Well_PL. The channel structures C may include the
channel layers 22A stacked over the substrate 20. Each of the
channel layers 22A may have the source region S and the well region
W. The vertical gates 24 may be located between the channel
structures C. The junctions 26 may be formed within the channel
layer 22A exposed between the vertical gates 24. The source line SL
may contact on the source regions S of the channel layers 22A and
extend in the direction crossing the channel structures C. The well
pickup line Well_PL may contact on the well regions W of the
channel layers 22A and extend in the direction crossing the channel
structures C.
[0039] In particular, source and drain regions of memory cells may
be easily formed. In addition, the source region S and the well
region W may be easily formed in each of the channel layers 22A
stacked over the substrate 20. Therefore, a program speed of the
memory device may be increased, and cell current may be increased,
thus ensuring a sensing margin. In addition, contact resistance
between the source line and the source region and between the well
pickup line and the well region may be reduced to improve an erase
speed.
[0040] FIG. 6 is a diagram illustrating a memory system according
to an embodiment of the present invention.
[0041] As illustrated in FIG. 6, a memory system 100 according to
an embodiment of the present invention includes a non-volatile
memory device 120 and a memory controller 110.
[0042] The non-volatile memory device 120 may have the structure
described in connection with FIGS. 2A to 5B. In addition, the
non-volatile memory device 120 may be a multi-chip package composed
of a plurality of flash memory chips.
[0043] The memory controller 110 is configured to control the
non-volatile memory device 120. The memory controller 110 may
include SRAM 111, a CPU 112, a host interface 113, an ECC 114 and a
memory interface 115. The SRAM 111 may function as an operation
memory of the CPU 112. The CPU 112 may perform the general control
operation for data exchange of the memory controller 110. The host
interface 113 may include a data exchange protocol of a host being
coupled to the memory system 100. In addition, the ECC 114 may
detect and correct errors included in data read from the
non-volatile memory device 120. The memory interface 115 may
perform to interface with the non-volatile memory device 120. The
memory controller 110 may further include RCM that stores code data
to interface with the host.
[0044] The memory system 100 having the above-described
configuration may be a solid state disk (SSD) or a memory card in
which the memory device 120 and the memory controller 110 are
combined. For example, when the memory system 100 is an SSD, the
memory controller 110 may communicate with the outside (e.g., a
host) through one of the interface protocols including USB, MMC,
PCI-E, SATA, PATA, SCSI, ESDI and IDE.
[0045] FIG. 7 is a block diagram illustrating a computing system
according to an embodiment of the present invention.
[0046] As shown in FIG. 7, a computing system 200 according to an
embodiment of the present invention may include a CPU 220, RAM 230,
a user interface 240, a modem 250 and a memory system 210 that are
electrically coupled to a system bus 260. In addition, when the
computing system 200 is a mobile device, a battery may be further
included to apply operating voltage to the computing system 200.
The computing system 200 may further include application chipsets,
a Camera Image Processor (CIS), and mobile DRAM.
[0047] As described above with reference to FIG. 6, the memory
system 210 may include a non-volatile memory 212 and a memory
controller 211.
[0048] A 3-D non-volatile memory device may have a well region
defined in each channel layer and have a junction formed between
memory cells. Therefore, a program speed may be improved, and cell
current may be increased, thus ensuring sensing margin. In
addition, contact resistance between a source line and a source
region and between a well pickup line and a well region may be
reduced to thus improve an erase speed.
* * * * *