U.S. patent application number 13/718980 was filed with the patent office on 2014-03-06 for semiconductor device and method for manufacturing the same.
This patent application is currently assigned to SK HYNIX INC.. The applicant listed for this patent is SK HYNIX INC.. Invention is credited to Woo Jun LEE, Seong Wan RYU.
Application Number | 20140061922 13/718980 |
Document ID | / |
Family ID | 50186356 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140061922 |
Kind Code |
A1 |
LEE; Woo Jun ; et
al. |
March 6, 2014 |
SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME
Abstract
A semiconductor device includes: a contact hole formed over a
structure including a conductive pattern; a contact plug formed in
the contact hole; a first metal silicide film surrounding the
contact plug; and a second metal silicide film formed over the
contact plug.
Inventors: |
LEE; Woo Jun; (Icheon-si,
KR) ; RYU; Seong Wan; (Yongin-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SK HYNIX INC. |
Icheon-si |
|
KR |
|
|
Assignee: |
SK HYNIX INC.
Icheon-si
KR
|
Family ID: |
50186356 |
Appl. No.: |
13/718980 |
Filed: |
December 18, 2012 |
Current U.S.
Class: |
257/755 ;
438/655 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 21/76897 20130101; H01L 21/7682 20130101; H01L 2924/0002
20130101; H01L 21/76852 20130101; H01L 21/76849 20130101; H01L
21/76877 20130101; H01L 23/53257 20130101; H01L 21/76843 20130101;
H01L 2924/00 20130101; H01L 21/76855 20130101; H01L 21/7688
20130101; H01L 21/76885 20130101; H01L 23/485 20130101; H01L
23/53271 20130101; H01L 21/76889 20130101; H01L 21/7685
20130101 |
Class at
Publication: |
257/755 ;
438/655 |
International
Class: |
H01L 23/532 20060101
H01L023/532; H01L 21/768 20060101 H01L021/768 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2012 |
KR |
10-2012-0096725 |
Claims
1. A semiconductor device comprising: an interlayer insulation film
formed over a structure including a conductive pattern; a contact
hole disposed in the interlayer insulation film and having a depth
sufficient to reach the structure including the conductive pattern,
the contact hole having a center portion and an edge portion; a
contact plug provided in the center portion of the contact hole; a
first metal silicide film provided in the edge portion of the
contact hole; and a second metal silicide film disposed over the
contact plug.
2. The semiconductor device according to claim 1, wherein the
contact plug includes a silicon material.
3. The semiconductor device according to claim 1, wherein the
contact plug includes a polysilicon material.
4. The semiconductor device according to claim 1, wherein the
second metal silicide film is diffused into the contact plug.
5-23. (canceled)
24. A semiconductor device comprising: a contact plug epitaxially
grown from a semiconductor substrate; a first metal silicide film
surrounding the contact plug; and a second metal silicide film
disposed over the contact plug.
25. The semiconductor device according to claim 24, wherein the
second metal silicide film is diffused into the contact plug.
26. A method for forming a semiconductor device comprising:
epitaxially growing a contact plug over a semiconductor substrate
using the semiconductor substrate as a seed layer; forming a
sacrificial insulation film spacer surrounding the contact plug;
forming an interlayer insulation film over the semiconductor
substrate; forming an air spacer by removing the sacrificial
insulation film spacer; forming a first metal silicide film in the
air spacer; and forming a second metal silicide film over the
contact plug.
27. The method according to claim 26, wherein forming the
sacrificial insulation film spacer includes: forming a sacrificial
insulation film over the contact plug; and etching back the
sacrificial insulation film.
28. The method according to claim 26, wherein the sacrificial
insulation film includes an oxide film or a nitride film.
29. The method according to claim 26, wherein forming the air
spacer includes performing a dip-out process removing the
sacrificial insulation film spacer.
30. The method according to claim 26, wherein forming the first
metal silicide film and the second metal silicide film includes:
forming a metal layer over the contact plug and the interlayer
insulation film to fill the air spacer; and performing a
silicification process on the metal layer.
31. The method according to claim 30, wherein the metal layer
includes titanium (Ti), nickel (Ni), tantalum (Ta), tungsten (W) or
cobalt (Co).
32. The method according to claim 26, wherein the second metal
silicide film is diffused into the contact plug.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The priority of Korean patent application No.
10-2012-0096725 filed on 31 Aug. 2012, the disclosure of which is
hereby incorporated in its entirety by reference, is claimed.
BACKGROUND OF THE INVENTION
[0002] Embodiments of the present invention relate to a contact of
a semiconductor device.
[0003] Typically, in order to reduce contact resistance of a
contact in a semiconductor device, a metal silicide layer is formed
between a contact region of a semiconductor substrate and a contact
or plug. That is, silicification in which silicon (Si) contained in
the contact region of the semiconductor substrate is reacted with a
metal material contained in a metal layer, which forms a metal
silicide film between the contact region and the contact, such that
contact resistance or interfacial resistance between the contact
and the contact region can be reduced.
[0004] Generally, it is known to those skilled in the art that a
cleaning process is performed to remove impurities from the surface
of the contact region, a metal layer is formed over the cleaned
contact region, and a silicification process is then performed on
the resultant metal layer in such a manner that a metal silicide
film can be effectively formed over the contact region.
BRIEF SUMMARY OF THE INVENTION
[0005] Various embodiments of the present invention are directed to
providing a semiconductor device and a method for manufacturing the
same that substantially obviate one or more problems due to
limitations and disadvantages of the related art.
[0006] An embodiment of the present invention relates to an
apparatus and method for solving the problems of the related art in
which the size of a contact hole is reduced due to increasing
integration of semiconductor devices, and the size of a metal
silicide film is correspondingly reduced, so that contact
resistance is increased.
[0007] In accordance with an aspect of the present invention, a
semiconductor device includes: an interlayer insulation film formed
over a structure including a conductive pattern; a contact hole
disposed in the interlayer insulation film and having a depth
sufficient to reach the structure including the conductive pattern,
the contact hole having a center portion and an edge portion;
contact plug provided in the center portion of the contact hole;
and a first metal silicide film including an inner part of the
contact hole; a second metal silicide film disposed over the
contact plug.
[0008] The contact plug may include a silicon material.
[0009] The contact plug may include a polysilicon material.
[0010] The second metal silicide film may be diffused into the
contact plug.
[0011] In accordance with another aspect of the present invention,
a method for forming a semiconductor device includes: forming an
interlayer insulation film over a structure including a conductive
pattern; etching the interlayer insulation film to form a contact
hole exposing the structure including the conductive pattern;
forming a sacrificial insulation film spacer in an edge portion of
the contact hole; forming a contact plug in a center portion of the
contact hole; removing the sacrificial insulation film spacer to
form an air spacer; forming a first metal silicide film in the air
spacer; and forming a second metal silicide film over the contact
plug.
[0012] The forming of the sacrificial insulation film spacer may
include forming a sacrificial insulation film over the interlayer
insulation film; and etching back the sacrificial insulation
film.
[0013] The sacrificial insulation film may include an oxide film or
a nitride film.
[0014] The contact plug may include a silicon material.
[0015] The contact plug may include a polysilicon material.
[0016] The forming of the air spacer may include performing a
dip-out process removing the sacrificial insulation film
spacer.
[0017] The forming of the first metal silicide film and the second
metal silicide film may include: forming a metal layer over the
contact plug and the interlayer insulation film to fill the air
spacer; and performing a silicification process on the metal
layer.
[0018] The metal layer may include titanium (Ti), nickel (Ni),
tantalum (Ta), tungsten (W) or cobalt (Co).
[0019] The second metal silicide film may be formed to be diffused
into the contact plug.
[0020] In accordance with another aspect of the present invention,
a method for forming a semiconductor device includes: forming a
contact plug over a structure including a conductive pattern;
forming a sacrificial insulation film spacer surrounding the
contact plug; forming an interlayer insulation film over the
structure including the conductive pattern; forming an air spacer
by removing the sacrificial insulation film spacer; and forming a
first metal silicide film in the air spacer, and forming a second
metal silicide film over the contact plug.
[0021] The forming of the contact plug may include: forming a
conductive layer over the structure including the conductive
pattern; forming a photoresist pattern over the conductive layer;
and etching the conductive layer using the photoresist pattern as a
mask.
[0022] The conductive layer may include a silicon material.
[0023] The conductive layer may include a polysilicon material.
[0024] The forming of the sacrificial insulation film spacer may
include: forming a sacrificial insulation film over the contact
plug; and etching back the sacrificial insulation film.
[0025] The sacrificial insulation film may include an oxide film or
a nitride film.
[0026] The forming of the air spacer may include performing a
dip-out process removing the sacrificial insulation film
spacer.
[0027] The forming of the first metal silicide film and the second
metal silicide film may include: forming a metal layer over the
contact plug and the interlayer insulation film to fill the air
spacer; and performing a silicification process on the metal
layer.
[0028] The metal layer may include titanium (Ti), nickel (Ni),
tantalum (Ta), tungsten (W) or cobalt (Co).
[0029] The second metal silicide film may be formed to be diffused
into the contact plug.
[0030] In accordance with another aspect of the present invention,
a semiconductor device includes: a contact plug epitaxially grown
from a semiconductor substrate; a first metal silicide film formed
surrounding the contact plug; and a second metal silicide film
formed over the contact plug.
[0031] The second metal silicide film may be formed to be diffused
into the contact plug.
[0032] In accordance with another aspect of the present invention,
a method for forming a semiconductor device includes: epitaxially
growing a contact plug over a semiconductor substrate using the
semiconductor substrate as a seed layer; forming a sacrificial
insulation film spacer surrounding the contact plug; forming an
interlayer insulation film over the semiconductor substrate;
forming an air spacer by removing the sacrificial insulation film
spacer; forming a first metal silicide film in the air spacer; and
forming a second metal silicide film over the contact plug.
[0033] The forming of the sacrificial insulation film spacer may
include: forming a sacrificial insulation film over the contact
plug; and etching back the sacrificial insulation film.
[0034] The sacrificial insulation film may include an oxide film or
a nitride film.
[0035] The forming of the air spacer may include performing a
dip-out process on the sacrificial insulation film spacer.
[0036] The forming of the first metal silicide film and the second
metal silicide film may include: forming a metal layer over the
contact plug and the interlayer insulation film so as to fill the
air spacer; and performing a silicification process on the metal
layer.
[0037] The metal layer may include titanium (Ti), nickel (Ni),
tantalum (Ta), tungsten (W) or cobalt (Co).
[0038] The second metal silicide film may be formed to be diffused
into the contact plug.
[0039] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] FIG. 1 illustrates a semiconductor device according to an
embodiment of the present invention. In FIG. 1, (i) is an isometric
view illustrating a contact plug, (ii) is a plan view illustrating
the contact plug, and (iii) is a cross-sectional view illustrating
the contact plug taken along the line X-X' of (i).
[0041] FIGS. 2A to 2D illustrate a method for forming a
semiconductor device according to an embodiment of the present
invention. In each of FIGS. 2A to 2D, (i) is an isometric view
illustrating a contact plug, (ii) is a plan view illustrating the
contact plug, and (iii) is a cross-sectional view illustrating the
contact plug taken along the line X-X' of (i).
[0042] FIGS. 3A to 3E are cross-sectional views illustrating a
method for forming a semiconductor device according to an
embodiment of the present invention.
[0043] FIG. 4 illustrates a semiconductor device according to
another embodiment of the present invention.
[0044] FIGS. 5A to 5E are cross-sectional views illustrating a
method for forming a semiconductor device according to an
embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0045] Reference will now be made in detail to embodiments of the
present invention, examples of which are illustrated in the
accompanying drawings. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same
or like parts.
[0046] FIG. 1 illustrates a semiconductor device according to an
embodiment of the present invention. In FIG. 1, (i) is an isometric
view illustrating a contact plug, (ii) is a plan view illustrating
the contact plug, and (iii) is a cross-sectional view illustrating
the contact plug taken along the line X-X' of (i).
[0047] Referring to FIGS. 1(i) and 1(ii), an embodiment of a
semiconductor device according to the present invention includes a
contact hole 104, a first metal silicide film 114, a contact plug
108, and a second metal silicide film 116. In more detail, the
contact hole 104 is disposed in an interlayer insulation film 102
formed over a structure 100 which includes a conductive pattern. A
first metal silicide film 114 is formed to surround the inside of
the contact hole 104. The contact plug 108 is formed in the first
metal silicide film 114 such that it is buried in the contact hole
104. The second metal silicide film 116 is disposed over the
contact plug 108, and in particular it is disposed over an upper
surface of the contact plug 108. Although the contact hole 104,
contact plug 108, and first metal silicide film 114 are illustrated
as having a cylindrical shape with a circular profile, the scope of
the present invention is not limited to a particular shape or
profile; for example, other embodiments may have a rectangular
profile.
[0048] In an embodiment, it is preferable that the contact plug 108
includes a silicon (Si) material. More specifically, it is
preferable that the contact plug 108 includes a polysilicon
material. The second metal silicide film 116 may be formed over the
contact plug 108, and may be partially diffused into the contact
plug 108. In addition, a width of an upper part of the contact hole
104 may be larger than a width of a lower part of the contact hole
104. However, the scope of the present invention is not limited
thereto, and the upper or lower part of the contact hole 104 may
have different widths according to relevant design considerations.
For convenience of description and better understanding of the
present invention, the figures and following description assume
that the width of the upper part of the contact hole 104 is that
the same as the width of the lower part of the contact hole
104.
[0049] Since the metal silicide film according to an embodiment of
the present invention includes a first metal silicide film
surrounding the inside of a contact hole and a second metal
silicide film formed over the contact plug, the area of the metal
silicide film is increased in size. In particular, the surface area
of the interface between silicide and the contact plug is
increased. Therefore, in an embodiment in which the size of the
contact hole is reduced, the area of the metal silicide film is not
reduced in size so that contact resistance is not increased.
[0050] A method for forming the above-mentioned semiconductor
device according to an embodiment of the present invention will
hereinafter be described with reference to FIGS. 2A to 2D.
[0051] FIGS. 2A to 2D illustrate a method for forming a
semiconductor device according to an embodiment of the present
invention. In each of FIGS. 2A to 2D, (i) is an isometric view
illustrating a contact plug, (ii) is a plan view illustrating the
contact plug, and (iii) is a cross-sectional view illustrating the
contact plug taken along the line X-X' of (i). FIGS. 2A to 2D
illustrate an embodiment in which a contact plug is formed over an
interlayer insulation film.
[0052] Referring to FIG. 2A(i), after forming an interlayer
insulation film 102 over the structure 100 including a conductive
pattern, a contact hole 102 is formed to expose the structure 100
including the conductive pattern. Subsequently, a sacrificial
insulation film is deposited over the interlayer insulation film
102 including a contact hole 104. In an embodiment, the sacrificial
insulation film may include an oxide film or a nitride film. In an
embodiment, an upper part of the contact hole 104 is larger in
width than a lower part of the contact hole 104. However, the scope
of the present invention is not limited thereto, and the width of
the contact hole 104 may be another width according to design
considerations of embodiments of the present invention. For
convenience of description and better understanding of the present
invention, the following description assumes that the upper part of
the contact hole 104 has the same width as the lower part
thereof.
[0053] Thereafter, the sacrificial insulation film is etched back
so that a sacrificial insulation film spacer 106 is formed to
surround a center portion of the contact hole 104. In other words,
sacrificial film spacer 106 is formed over the inner sidewall of
contact hole 104. Then a contact plug 108 is formed to fill the
center portion of contact hole 104. Preferably, the contact plug
108 may include a silicon (Si) material, more specifically, a
polysilicon material.
[0054] Therefore, as shown in FIGS. 2A(ii) and 2A(iii), the
sacrificial insulation film 106 and the contact plug 108 are buried
in the contact hole 104 contained in the interlayer insulation film
102.
[0055] Referring to FIG. 2B(i), the sacrificial insulation film
spacer 106 is etched to expose the structure 100 including the
conductive pattern, such that an air-spacer 110 is formed between
the contact hole 104 and the contact plug 108. Preferably, the
sacrificial insulation film spacer 106 may be etched using a
dip-out process. During the dip-out process, impurities remaining
on the surface of the structure 100 including the conductive
pattern and impurities on a sidewall of the contact plug 108 can be
simultaneously removed.
[0056] Accordingly, as shown in FIG. 2B(ii) and 2B(iii), the air
spacer 110 is formed between the sidewall of the interlayer
insulation film 102 exposed by the contact hole 104 and the contact
plug 108 contained in the contact hole 104, so that the structure
100 including the conductive pattern is exposed.
[0057] Referring to FIG. 2C(i), a metal layer 112 is formed not
only in the air spacer 110 but also over the contact plug 108 and
the interlayer insulation film 102. Preferably, the metal layer 112
may include titanium (Ti), nickel (Ni), tantalum (Ta), tungsten (W)
or cobalt (Co).
[0058] Therefore, as shown in FIGS. 2C(ii) and 2C(iii), the metal
layer 112 is buried between the interlayer insulation film 102 and
the contact plug 108, and is formed over the interlayer insulation
film 102 and the contact plug 108.
[0059] Referring to FIG. 2D(i), a silicification process is
performed on the metal layer 112 to form a metal silicide film 118.
Here, the silicification process may include a heat treatment or
annealing process, and fabrication conditions such as temperature
and time of the silicification process may be changed according to
properties of the material of metal layer 112. In addition, in
order to facilitate transformation from the metal layer 112 into
the metal silicide film 118, the metal layer 112 may be formed to
have a thickness of less than 10 nm. Then, the reminded metal layer
112 is etched.
[0060] The metal silicide film 118 includes a first metal silicide
film 114 surrounding a sidewall of the contact plug 108 and a
second metal silicide film 116 formed over the contact plug 108.
The second metal silicide film 116 may be formed over the contact
plug 108 according to silicification conditions or properties of
the metal layer 112, and may be partially diffused into the contact
plug 108.
[0061] Therefore, as can be seen from FIGS. 2D(ii) and 2D(iii), the
metal silicide film 118 includes: a first metal silicide film 114
interposed between a sidewall of the contact hole 104 and a
sidewall of the contact plug 108; and a second metal silicide film
116 formed over the contact plug 108.
[0062] As a result, the area of the metal silicide film is
increased relative to a conventional configuration. Thus, when a
contact hole is reduced in size to create a higher density device,
the area of the metal silicide film is not reduced, such that
contact resistance is not increased.
[0063] An embodiment in which a contact plug is formed over an
interlayer insulation film will hereinafter be described with
reference to FIGS. 3A to 3E.
[0064] FIGS. 3A to 3E are cross-sectional views illustrating a
method for forming a semiconductor device according to an
embodiment of the present invention.
[0065] Referring to FIG. 3A, a contact plug 202 is formed over a
structure 200 including a conductive pattern. In an embodiment, the
contact plug 202 may include a silicon (Si) material. More
preferably, the contact plug 202 may include polysilicon. In
accordance with a method for forming the contact plug 202, after a
polysilicon film is formed over the structure 200 including a
conductive pattern, the polysilicon film is etched using a
predetermined photoresist pattern as an etch mask such that the
contact plug 202 is formed.
[0066] Referring to FIG. 3B, a sacrificial insulation film spacer
204 is formed over a sidewall of the contact plug 202. In
accordance with a method for forming the sacrificial insulation
film spacer 204, a sacrificial insulation film is formed over the
upper surface of the semiconductor device including the contact
plug 202, and an etchback process is performed on the resultant
structure so that the sacrificial insulation film spacer 204 is
formed. In an embodiment, the sacrificial insulation film spacer
204 surrounds the contact plug 202. Preferably, the sacrificial
insulation film may include an oxide film or a nitride film.
[0067] Referring to FIG. 3C, an interlayer insulation film 210 is
formed over the structure 200 including a conductive pattern over
which the sacrificial insulation film spacer 204 is formed.
Thereafter, the sacrificial insulation film spacer 204 is removed
to expose the structure 200 including the conductive pattern, such
that the air spacer 208 is formed. In an embodiment, the
sacrificial insulation film spacer 204 may be removed using the
dip-out process.
[0068] Referring to FIG. 3D, the metal layer 312 is formed over the
contact plug 202 and the interlayer insulation film 210 to fill the
air spacer 208. Preferably, the metal layer 212 may include
titanium (Ti), nickel (Ni), tantalum (Ta), tungsten (W) or cobalt
(Co).
[0069] Referring to FIG. 3E, a silicification process is performed
on the metal layer 212 to form a metal silicide film 218. Here, the
silicification process may include a heat treatment or annealing
process, and fabrication conditions such as temperature and time of
the silicification process may be changed according to properties
of the metal layer 212. In addition, in order to facilitate
transformation from the metal layer 212 to the metal silicide film
218, the metal layer 212 may be formed to have a thickness of less
than 10 nm.
[0070] The metal silicide film 218 includes a first metal silicide
film 214 surrounding a sidewall of the contact plug 202 and a
second metal silicide film 216 formed over the contact plug 202.
The second metal silicide film 216 may be formed over the contact
plug 202 according to silicification conditions or properties of
the metal layer 212, and may be partially diffused into the contact
plug 202.
[0071] As described above, in an embodiment, a contact plug and
silicide films can be formed without first forming a contact hole
in an insulation layer.
[0072] A semiconductor device in which a contact plug is formed
over a semiconductor substrate according to another embodiment of
the present invention will hereinafter be described with reference
to FIG. 4.
[0073] FIG. 4 illustrates a semiconductor device according to an
embodiment of the present invention.
[0074] Referring to FIG. 4, a semiconductor device according to an
embodiment of the present invention includes an epitaxial growth
layer 302 grown from a semiconductor substrate 300; a first metal
silicide film 314 surrounding the epitaxial growth layer 302; and a
second metal silicide film 316 formed over the epitaxial growth
layer 302. In an embodiment, the second metal silicide film 316 is
disposed over the epitaxial growth layer 302, and may be partially
diffused into the epitaxial growth layer 302.
[0075] Since the metal silicide film according to an embodiment of
the present invention includes the first metal silicide film
surrounding the epitaxial growth layer grown from the semiconductor
substrate and the second metal silicide film formed over the
epitaxial growth layer, the entire metal silicide film is increased
in size, which may reduce contact resistance of a contact plug at
an interface between a metal and a silicon.
[0076] A method for forming a semiconductor device in which a
contact plug is formed over a semiconductor substrate according to
an embodiment of the present invention will hereinafter be
described with reference to FIGS. 5A to 5E. FIGS. 5A to 5E are
cross-sectional views illustrating a method for forming a
semiconductor device according to an embodiment of the present
invention using an epitaxial growth process.
[0077] Referring to FIG. 5A, a contact plug 302 is epitaxially
grown from a semiconductor substrate 300. In accordance with a
method for forming the contact plug 302, after an interlayer
insulation film (not shown) with holes exposing contact regions of
the semiconductor substrate is formed over the semiconductor
substrate 300, an epitaxial growth process is performed using the
semiconductor substrate 300 as a seed layer to form contact plug
302.
[0078] Referring to FIG. 5B, a sacrificial insulation film spacer
304 is formed over a sidewall of the epitaxial growth layer spacer
302 to en. In order to form the sacrificial insulation film spacer
304, a sacrificial insulation film is formed over the semiconductor
substrate 300 including the contact plug 302, and is then etched
back such that the sacrificial insulation film spacer 304 can be
formed. In an embodiment, the sacrificial insulation film may
include an oxide film or a nitride film.
[0079] Referring to FIG. 5C, an interlayer insulation film 310 is
formed over the semiconductor substrate 300, and planarized to
expose upper surfaces of the contact plug 302 and the sacrificial
insulation film spacer 304. Thereafter, the sacrificial insulation
film spacer 304 is removed to expose the semiconductor substrate
300 so that an air spacer 308 is formed. Preferably, the
sacrificial insulation film spacer 304 may be removed using the
dip-out process.
[0080] Referring to FIG. 5D, a metal layer 312 is formed over the
contact plug 302 and the interlayer insulation film 310 to fill the
air spacer 308. In an embodiment, the metal layer 312 may include
titanium (Ti), nickel (Ni), tantalum (Ta), tungsten (W) or cobalt
(Co).
[0081] Referring to FIG. 5E, a silicification process is performed
on the metal layer 312 to form a metal silicide film 318. The
silicification process may include a heat treatment or annealing
process, and fabrication conditions such as temperature and time of
the silicification process may be determined according to
properties of the metal layer 312. In addition, in order to
facilitate transformation from the metal layer 312 to the metal
silicide film 318, the metal layer 312 may be formed to have a
thickness of less than 10 nm.
[0082] The metal silicide film 318 includes a first metal silicide
film 314 surrounding the contact plug 302 and a second metal
silicide film 316 formed over the contact plug 302. The second
metal silicide film 316 may be formed over the epitaxial growth
layer 302 by performing silicification on corresponding regions of
the metal layer 312, and may be partially diffused into the contact
plug 302. Then, the reminded metal layer 312 is etched.
[0083] Since the metal silicide film according to an embodiment of
the present invention includes the first metal silicide film
surrounding the epitaxial growth layer grown from the semiconductor
substrate and the second metal silicide film formed over the
epitaxial growth layer, embodiments of the present invention may
have favorable contact resistance characteristics.
[0084] As is apparent from the above description, although a
contact plug is reduced in size due to higher integration of a
semiconductor device, the region of the metal silicide film can be
increased relative to a device where silicide is only present at a
junction, such that contact resistance can be reduced and
semiconductor device characteristics can be improved.
[0085] The above embodiments of the present invention are
illustrative and not limitative. Various alternatives and
equivalents are possible. The invention is not limited by the
embodiments described herein. Nor is the invention limited to any
specific type of semiconductor device. Other additions,
subtractions, or modifications are obvious in view of the present
disclosure and are intended to fall within the scope of the
appended claims.
* * * * *