U.S. patent application number 11/386644 was filed with the patent office on 2006-07-27 for methods of forming a semiconductor device having a metal gate electrode and associated devices.
This patent application is currently assigned to Samsung electronic Co., Ltd.. Invention is credited to Gil-Heyun Choi, Si-Young Choi, Seong-Jun Heo, Sung-Man Kim, Ja-Hum Ku, Chang-Won Lee, Jong-Myeong Lee, Kwon-Sun Ryu, Sun-Pil Youn.
Application Number | 20060163677 11/386644 |
Document ID | / |
Family ID | 36695889 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060163677 |
Kind Code |
A1 |
Heo; Seong-Jun ; et
al. |
July 27, 2006 |
Methods of forming a semiconductor device having a metal gate
electrode and associated devices
Abstract
Methods of forming a semiconductor device having a metal gate
electrode include sequentially forming a gate insulator, a gate
polysilicon layer and a metal-gate layer on a semiconductor
substrate. The metal-gate layer and the gate polysilicon layer are
sequentially patterned to form a gate pattern comprising a stacked
gate polysilicon pattern and a metal-gate pattern. An oxidation
barrier layer is formed to cover at least a portion of a sidewall
of the metal-gate pattern.
Inventors: |
Heo; Seong-Jun; (Seoul,
KR) ; Youn; Sun-Pil; (Seoul, KR) ; Kim;
Sung-Man; (Gyeonggi-do, KR) ; Choi; Si-Young;
(Gyeonggi-do, KR) ; Choi; Gil-Heyun; (Gyeonggi-do,
KR) ; Ku; Ja-Hum; (Gyeonggi-do, KR) ; Lee;
Chang-Won; (Gyeonggi-do, KR) ; Lee; Jong-Myeong;
(Gyeonggi-do, KR) ; Ryu; Kwon-Sun; (Gyeonggi-do,
KR) |
Correspondence
Address: |
MYERS BIGEL SIBLEY & SAJOVEC
PO BOX 37428
RALEIGH
NC
27627
US
|
Assignee: |
Samsung electronic Co.,
Ltd.
|
Family ID: |
36695889 |
Appl. No.: |
11/386644 |
Filed: |
March 22, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10780244 |
Feb 17, 2004 |
|
|
|
11386644 |
Mar 22, 2006 |
|
|
|
Current U.S.
Class: |
257/410 ;
257/411; 257/412; 257/E21.2; 257/E29.157; 257/E29.165;
257/E29.266 |
Current CPC
Class: |
H01L 21/28088 20130101;
H01L 29/4966 20130101; H01L 29/7833 20130101; H01L 29/6659
20130101; H01L 29/4941 20130101; H01L 21/28061 20130101 |
Class at
Publication: |
257/410 ;
257/411; 257/412; 257/E29.165 |
International
Class: |
H01L 29/94 20060101
H01L029/94 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 19, 2003 |
KR |
10-2003-0010403 |
Claims
1. A highly integrated semiconductor circuit device with metal gate
electrodes and a reduced gate pattern size, comprising: a
substrate; a gate insulation layer disposed over the substrate; a
plurality of spaced apart first gate layer patterns stacked on the
gate insulation layer above the substrate; a plurality of spaced
apart barrier metal patterns, a respective one stacked on each of
the first gate layer patterns above the gate insulation layer, the
barrier metal patterns having at least one upwardly extending
sidewall; a plurality of metal gate patterns, a respective one
stacked on each of the barrier metal patterns above the first gate
layer pattern, the metal gate patterns having at least one upwardly
extending sidewall; a plurality of capping patterns, a respective
one stacked on each of the metal gate patterns above the barrier
metal pattern; and an oxidation barrier layer conformably disposed
over the barrier metal pattern sidewalls and the metal gate pattern
sidewalls and being substantially absent on sidewalls of the first
gate layer patterns and the sidewalls of the capping layer pattern,
wherein the device is substantially devoid of an oxide layer
extending at a boundary portion located between respective barrier
metal patterns and the corresponding first gate layer patterns.
2. A device according to claim 1, wherein the oxidation barrier
layer has a thickness of between about 5.about.100 .ANG..
3. A device according to claim 1, wherein the first gate layer
patterns comprise gate polysilicon patterns.
4. A device according to claim 3, wherein the barrier metal pattern
is directly stacked on the gate polysilcon pattern.
5. A device according to claim 4, wherein the oxidation barrier
layer comprises metal.
6. A device according to claim 4, wherein the barrier and/or metal
gate patterns comprise tungsten.
7. A device according to claim 1, wherein the barrier metal pattern
comprises tungsten nitride (WN) or titanium nitride (TiN).
8. A semiconductor device with a metal gate electrode, comprising:
a semiconductor substrate; and a metal gate electrode on the
substrate, the metal gate electrode comprising a stacked gate
pattern comprising a gate polysilicon pattern, a barrier metal
pattern on the gate polysilicon pattern, and a metal gate pattern
on the barrier metal pattern, wherein the device is substantially
devoid of an oxide layer extending at a boundary portion located
between the barrier metal pattern and the gate polysilicon
pattern.
9. A device according to claim 8, wherein the barrier and/or metal
gate patterns comprises tungsten.
10. A device according to claim 8, wherein the barrier metal layer
comprises tungsten nitride (WN) or titanium nitride (TiN).
11. A device according to claim 8, further comprising an oxidation
barrier layer, wherein the oxidation barrier layer covers
substantially only sidewall(s) of the metal gate pattern and the
barrier metal pattern.
12. A device according to claim 8, further comprising a capping
layer on the metal gate pattern layer, wherein the capping layer is
patterned thereby forming a device with the stacked gate pattern
that comprises, in serial order, the gate polysilicon pattern, the
metal-gate pattern and the capping pattern.
13. A device according to claim 11, further comprising a spacer
layer abutting a sidewall of the stacked gate pattern including a
sidewall(s) of the polysilicon gate pattern, a sidewall(s) of the
oxidation barrier layer that resides over the sidewall(s) of the
metal-gate pattern and the barrier metal pattern, and a sidewall(s)
of the capping pattern.
14. A device according to claim 8, further comprising an
impurity-doped region in the semiconductor substrate at opposing
sides of the stacked gate pattern.
15. A device according to claim 11, wherein the oxidation layer
comprises aluminum.
16. A device according to claim 12, further comprising an oxidation
barrier layer, wherein the oxidation barrier layer covers
substantially only sidewall(s) of the metal gate pattern and the
barrier metal pattern such that the gate polysilicon pattern and
the capping pattern are devoid of the oxidation barrier layer.
17. A semiconductor device with a metal gate electrode, comprising:
a semiconductor substrate; a metal gate electrode on the substrate,
the metal gate electrode comprising a stacked gate pattern
comprising a gate polysilicon pattern, a barrier metal pattern on
the gate polysilicon pattern, and a metal gate pattern on the
barrier metal pattern, and a capping pattern on the metal gate
pattern; and an oxidation barrier layer, wherein the oxidation
barrier layer covers substantially only sidewall(s) of the metal
gate pattern and the barrier metal pattern such that the gate
polysilicon pattern and the capping pattern are devoid of the
oxidation barrier layer, wherein the device is substantially devoid
of an oxide layer extending at a boundary portion located between
the barrier metal pattern and the gate polysilicon pattern.
18. A device according to claim 17, wherein the oxidation barrier
layer has a thickness of between about 5.about.100 .ANG..
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/780,244, filed Feb. 17, 2004, which claims priority to
Korean Patent Application No. 10-2003-0010403, filed Feb. 19, 2003,
the contents of which are hereby incorporated by reference as if
recited in full herein.
FIELD OF THE INVENTION
[0002] The present invention relates to methods of forming
semiconductor devices. More particularly, the present invention
relates to methods of forming semiconductor devices having a metal
gate electrode.
BACKGROUND OF THE INVENTION
[0003] As semiconductor devices become more highly integrated, the
size of gate patterns can be reduced which can change an electrical
property associated with the gate pattern. For example, where a
metal silicide, such as tungsten silicide, is used as a gate
pattern, resistance of the gate pattern can increase (sometimes
relatively rapidly) as size of the gate pattern is reduced. Thus,
in order to adjust for the resistance increase caused by the
reduced size gate pattern in a highly integrated semiconductor
device, a metal (such as tungsten) having a low resistance can be
used to offset the increased resistance caused by the reduced size
gate pattern. FIG. 1 is a cross-sectional diagram of a
semiconductor device having a metal gate electrode according to the
prior art. Referring to FIG. 1, a gate insulator 3, a gate
polysilicon layer 5, a barrier metal layer 7, a metal gate layer 9,
and a capping layer 11 are sequentially formed and patterned to
form a gate pattern 13. In order to treat etch damage that can
occur at the semiconductor substrate 1 and the gate polysilicon
layer 5 during the patterning process, a thermal treatment process
can be performed in an oxygen environment. At this time, as through
a side surface of the metal gate layer 9 while thermal treating
under the oxygen environment, thereby forming an oxide layer "O" at
a boundary between the metal barrier layer 7 and the gate
polysilicon layer 5. The oxide layer "O" may increase resistance
between the metal gate layer 9 and the gate polysilicon layer 5.
The increased resistance attributed to the oxide layer may result
in one or more of an RC (time constant) delay, a lower operational
speed and reliability in a semiconductor device.
SUMMARY
[0004] Embodiments of the invention provide methods of forming a
semiconductor device that can inhibit and/or prevent oxide
formation between a metal gate layer and a gate polysilicon layer
in a gate pattern.
[0005] Certain embodiments of the invention are directed to methods
that include forming an oxidation barrier layer covering at least a
portion of a sidewall of a metal gate layer.
[0006] In particular embodiments, the method can include:
sequentially forming a gate insulator, a gate polysilicon layer and
a metal-containing layer on a semiconductor substrate. The
metal-containing layer and the gate polysilicon layer can be
(sequentially) patterned to form a gate pattern comprising a
stacked gate polysilicon pattern and a metal-gate (comprising a
metal containing) pattern.
[0007] The method can include forming an oxidation barrier layer to
cover at least a portion of a sidewall of the metal-containing
pattern. In particular embodiments, the oxidation barrier layer can
be formed by chemical vapor deposition (CVD) and/or an atomic layer
deposition (ALD).
[0008] In certain embodiments, the oxidation barrier layer can be
deposited on sidewalls of the metal-containing layer with a greater
thickness than on surfaces of other layers due to a difference of
chemical properties in the material of the other layers, such as
nucleation rate.
[0009] The oxidation barrier layer may comprise at least one of a
metal, an oxide, a nitride or an oxynitride of the metal. In
particular embodiments, the metal can be selected from the group
consisting of aluminum (Al), tantalum (Ta), titanium (Ti), hafnium
(Hf) and gold (Au).
[0010] The oxidation barrier layer may be formed by selectively
depositing a metal layer onto the sidewall(s) of the metal-gate
pattern and then oxidizing or nitrifying the deposited metal
layer.
[0011] In particular embodiments, the oxidation barrier layer may
comprise and/or be formed of aluminum oxide (Al.sub.2O.sub.3). For
example, an aluminum layer can be formed by using a CVD method and
by supplying methylpyrrolidine alane (MPA) as a source gas and
argon (Ar) of 100 sccm as a carrier gas at a temperature of between
about 135.about.145.degree. C. and at a pressure of between about
0.1.about.1.1 Torr, and the aluminum layer can be oxidized under an
oxygen-enriched environment or ambience.
[0012] According to another embodiment of the present invention,
the metal-containing layer can be formed of a barrier metal layer
and a metal gate layer that are sequentially stacked. The gate
pattern can comprise a gate polysilicon pattern, a barrier metal
pattern and a metal gate pattern that are sequentially stacked. In
particular embodiments, the metal gate layer can comprise tungsten.
The barrier metal layer can comprise tungsten nitride (WN) and/or
titanium nitride (TiN). The oxidation barrier layer may be
selectively formed to cover substantially only the metal gate
pattern.
[0013] In certain embodiments, the methods can include forming a
capping layer on the metal-containing layer. The capping layer can
be patterned when the metal-containing layer and the gate
polysilicon layer are sequentially patterned, thereby forming a
gate pattern comprising a gate polysilicon pattern, a
metal-containing pattern and a capping pattern that are
sequentially stacked.
[0014] In particular embodiments, a thermal treating process may be
subsequently performed with respect to the semiconductor substrate
having the gate pattern with the oxidation barrier layer under an
oxygen-enriched environment or ambience. The thermal treating
process under the oxygen environment may comprise supplying
nitrogen as a carrier gas and supplying oxygen and hydrogen at a
temperature of between about 750.about.950.degree. C. with a ratio
of oxygen/hydrogen of between about 0.5.about.1.3.
[0015] The oxidation barrier layer can inhibit oxygen penetration
into the metal-containing layer so that there is a reduced and/or
no formation of a conventional oxide layer between the gate
polysilicon pattern and the metal-containing pattern.
[0016] Still other embodiments are directed to methods of forming
an integrated circuit device having a metal gate electrode. The
methods include: (a) forming a stacked gate pattern onto a target
substrate, the gate pattern comprising a metal-gate pattern with
opposing first and second surfaces and at least one sidewall; and
(b) covering at least a portion of the at least one sidewall of the
metal-gate pattern with an oxidation barrier layer.
[0017] In particular embodiments, the covering of the at least one
sidewall of the metal-gate pattern comprises conformably covering
substantially the entire outer surface of the sidewall(s) of the
metal-gate pattern with the oxidation barrier layer, and, as
desired also covering the sidewalls of a barrier metal layer
abutting the metal-gate pattern. The gate pattern can be formed so
that it is substantially devoid of the oxidation barrier layer
proximate to a sidewall of a respective gate polysilicon pattern
and a capping pattern.
[0018] In certain embodiments, the method can include thermally
treating the gate pattern in an oxygen-enriched environment and
inhibiting an oxide layer from forming between the metal-barrier
layer and the gate polysilicon layer based on the configuration of
the oxidation barrier layer.
[0019] Other embodiments are directed to highly integrated
semiconductor circuit devices with metal gate electrodes and a
reduced gate pattern size. The devices include: (a) a substrate;
(b) a gate insulation layer disposed over the substrate; (c) a
plurality of spaced apart first gate patterns stacked on the gate
insulation layer above the substrate; (d) a plurality of
corresponding spaced apart metal barrier patterns, a respective one
stacked on each of the first gate patterns above the gate
insulation layer, the metal barrier patterns having at least one
upwardly extending sidewall; (e) a plurality of corresponding
second metal gate patterns, a respective one stacked on each of the
metal barrier patterns above the first gate layer, the second metal
gate patterns having at least one upwardly extending sidewall; (f)
a plurality of corresponding capping patterns, a respective one
stacked on each of the metal gate patterns above the metal barrier
layer; and (g) an oxidation barrier layer conformably disposed over
the metal barrier pattern sidewalls and the metal gate pattern
sidewalls and being substantially absent on sidewalls of the first
gate patterns and the sidewalls of the capping layer pattern. The
device is substantially devoid of an oxide layer extending at a
boundary portion located between respective metal barrier patterns
and the corresponding first gate layers. The oxidation barrier
layer may have a thickness of between about 5.about.100 .ANG..
[0020] The foregoing and other objects and aspects of the present
invention are described in greater detail in the drawings herein
and the specification set forth below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a cross-sectional diagram of a prior art
semiconductor device having a metal gate electrode according to a
conventional technology.
[0022] FIGS. 2A through 2C are cross-sectional diagrams
sequentially illustrating exemplary operations and/or features for
forming a semiconductor device having a metal gate electrode
according to embodiments of the present invention.
DETAILED DESCRIPTION
[0023] The present invention will now be described more fully
hereinafter with reference to the accompanying drawings, in which
embodiments of the invention are shown. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. Rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art.
[0024] In the drawings, the thickness of layers and regions may be
exaggerated for clarity. It will be understood that when an element
such as a layer, region or substrate is referred to as being "on"
another element, it can be directly on the other element or
intervening elements may also be present.
[0025] Furthermore, relative terms, such as "beneath", may be used
herein to describe one element's relationship to another elements
as illustrated in the figures. It will be understood that relative
terms are intended to encompass different orientations of the
device in addition to the orientation depicted in the figures. For
example, if the device in the figures is turned over, elements
described as "below" other elements would then be oriented "above"
the other elements. The exemplary term "below", can therefore,
encompasses both an orientation of above and below.
[0026] It will be understood that although the terms first and
second may be used herein to describe various regions, layers
and/or sections, these regions, layers and/or sections should not
be limited by these terms. These terms are used to distinguish one
region, layer or section from another region, layer or section.
Thus, a first region, layer or section discussed below could be
termed a second region, layer or section, and similarly, a second
without departing from the teachings of the present invention. Like
numbers refer to like elements throughout. In addition, although
described herein with respect to semiconductor substrates and
devices, the present invention is directed to integrated circuits
and can include structures formed on other substrates.
[0027] FIGS. 2A through 2C are cross-sectional diagrams
sequentially illustrating exemplary operations and/or features of
forming a semiconductor device having a metal gate electrode
according to embodiments of the present invention.
[0028] Referring to FIG. 2A, a gate insulator 110, a gate
polysilicon layer 120, a barrier metal layer 130, a metal gate
layer 140 and a capping layer 150 can be sequentially stacked on a
semiconductor substrate 100. The capping layer 150, the metal gate
layer 140, the barrier metal layer 130, and the gate polysilicon
layer 120 can be (sequentially) patterned to form a gate pattern
155. As such, the gate pattern 155 can comprise stacked gate layers
of corresponding patterns: a polysilicon pattern 120, a barrier
metal pattern 130, a metal gate pattern 140, and a capping pattern
150. The terms "layer" and "pattern" may be used interchangeably
below to indicate the stacked components on the semiconductor or
other base substrate forming the gate pattern.
[0029] The gate insulator 110 may be formed by thermally oxidizing
the semiconductor substrate 100. The gate insulator 110 may be
removed during the patterning process to expose the semiconductor
substrate 100, and subsequently formed again by a thermal treatment
process. The barrier metal layer 130 may comprise tungsten nitride
(WN) and/or titanium nitride (TiN) that may be formed by a physical
vapor deposition (PVD) or a chemical vapor deposition (CVD). The
metal gate layer 140 may comprise tungsten. The gate polysilicon
layer 120 may comprise polysilicon doped by impurities. The capping
layer 150 may comprise silicon oxide and/or silicon nitride.
[0030] Referring to FIG. 2B, an oxidation barrier layer 160 can be
selectively formed on at least portions of the sidewalls of the
metal gate pattern 140 and on at least sidewalls (and typically at
least a major portion of the primary upper and lower surfaces) of
the barrier metal pattern 130. The oxidation barrier layer 160 can
comprise metal as a constituent or the constituent forming the
oxidation barrier layer 160. In certain embodiments, the oxidation
barrier layer 160 may be configured so as to cover substantially
only the sidewalls of the metal gate pattern 140. In other
embodiments, the oxidation barrier layer 160 may be configured to
cover only the lower portion of the sidewall(s) of the metal-gate
pattern 140. The oxidation barrier layer 160 may be formed by any
suitable process, including but not limited to, chemical vapor
deposition (CVD) or atomic layer deposition (ALD).
[0031] In particular embodiments, the oxidation barrier layer 160
can be relatively well-deposited (with a desired thickness) on
sidewalls of the metal containing layers 130 and 140 but deposited
in substantially reduced amounts, regions or thickness on surfaces
of other layers, including adjacent layers or patterns 120 and 150
or more remote layer 110. This differential or selectivity may be
carried out using differences in chemical properties of materials
forming or coating the layers, such as a nucleation rate.
[0032] In certain embodiments, in order to form the oxidation
barrier layer 160, a metal layer can be (selectively) deposited and
the deposited metal layer can be treated to form a metal oxide or
metal nitride barrier layer. The oxidation barrier layer 160 can be
formed with a thickness of between about 5.about.100 .ANG..
[0033] In certain embodiments, such as when the oxidation barrier
layer 160 is formed of aluminum oxide (Al.sub.2O.sub.3), an
aluminum layer may be formed substantially only on sidewalls of the
metal-containing layers 130 and 140 by supplying methylpyrrolidine
alane (MPA) as a source gas and argon (Ar) of as a carrier gas.
Typically the Ar is supplied at about 100 sccm, at a temperature of
between about 135.about.145.degree. C. at a pressure of between
about 0.1.about.1.1 Torr for about 5 seconds using a CVD method.
The aluminum layer can be naturally oxidized (at pressures at about
and/or under atmospheric pressure) to form the aluminum oxide for
the oxidation barrier layer 160. The aluminum layer may be
selectively deposited on surfaces of the metal containing layers
130, 140 but substantially not on other adjacent layers 110, 120
and 150.
[0034] Referring to FIG. 2C, a thermal treatment process can be
performed with respect to the semiconductor substrate 100 having
the gate pattern 155 with the oxidation barrier layer 160 under an
oxygen-enriched environment or ambience, thereby curing etch damage
caused during the patterning process (such as results in the
pattern shown in FIG. 2A). The thermal treatment process under the
oxygen-enriched environment or ambience may be performed by
supplying nitrogen (N.sub.2) as a carrier gas and supplying
hydrogen (H2) and oxygen (O.sub.2) at a temperature of between
about 750.about.950.degree. C. In particular embodiments, the ratio
of oxygen/hydrogen may be between about 0.5.about.1.3. The
oxidation barrier layer 160 can inhibit and/or prevent oxygen
penetration into the metal gate pattern 140 to inhibit formation of
an oxide layer between the metal gate pattern 140 and the gate
polysilicon pattern 120. This, in turn, may improve reliability
and/or operational speed in a semiconductor device, particularly a
highly integrated semiconductor device with reduced size gate
patterns and/or metal gate electrodes.
[0035] Still referring to FIG. 2C, a low concentration
impurity-doped region 170 can be formed in the semiconductor
substrate 100 at both sides of the gate pattern 155 by using the
gate pattern 155 as an ion-implantation mask. The low concentration
impurity-doped region 170 may be formed before forming the
oxidation barrier layer 160 by implanting impurities using the gate
pattern 155 as an ion-implantation mask.
[0036] In operation, an insulation layer can be conformably formed
at an entire upper surface above the semiconductor substrate 100,
extending from where the capping layer 150 or oxidation barrier
layer 160 is formed down to the gate insulation layer 110. The
insulation layer can be anisotropically etched to form spacers 180
covering sidewalls of the individually stacked layers 120, 130,
140, 150 that together form the sidewalls of the gate pattern 155.
The insulation layer may comprise silicon oxide or silicon nitride.
A relatively high concentration impurity-doped region 190 can be
formed in the semiconductor substrate 100 by using the gate pattern
155 and the spacer 180 as ion-implantation masks.
[0037] The gate pattern 155 may include a plurality of opposing
sidewalls where the shape of the gate pattern 155 (when viewed from
the top) is rectangular, square or other shape with more than one
sidewall. However, the gate pattern 155 can include cylindrical,
circular, or other shapes with only one sidewall as well as other
multi-sided configurations. Hence, in the claims, the term
"sidewall(s)" is intended to encompass both these sidewall
configurations. In addition, although a respective one gate pattern
155 is illustrated, a highly integrated device can comprise a
plurality of the gate patterns 155, repeated on the substrate, as
will be understood by one of skill in the art.
[0038] Accordingly, methods of forming semiconductor devices
according to embodiments of the present invention can form an
oxidation barrier layer covering at least a portion of the sidewall
of the metal gate pattern layer, thereby inhibiting and/or
preventing formation of an oxide layer between the metal gate
pattern and the gate polysilicon pattern which may occur due to
oxygen penetration in a subsequent process.
* * * * *