U.S. patent application number 11/122834 was filed with the patent office on 2006-05-11 for method for forming capacitor of semiconductor device.
Invention is credited to Kwon Hong, Deok Sin Kil.
Application Number | 20060099769 11/122834 |
Document ID | / |
Family ID | 36216002 |
Filed Date | 2006-05-11 |
United States Patent
Application |
20060099769 |
Kind Code |
A1 |
Hong; Kwon ; et al. |
May 11, 2006 |
METHOD FOR FORMING CAPACITOR OF SEMICONDUCTOR DEVICE
Abstract
Disclosed is a method for forming a capacitor of a semiconductor
device, which can ensure charging capacity required as well as an
excellent leakage current characteristic. In such a method, a
storage electrode consisting of TiN is formed on a semiconductor
substrate. Then, a first HfO2 thin film, an HfxAlyOz thin film and
a second HfO2 thin film are successively deposited on the storage
electrode using Atomic layer Deposition (ALD) processes to form an
HfO2/HfxAlyOz/HfO2 dielectric film. Finally, a plate electrode
consisting of TiN is formed on the HfO2/HfxAlyOz/HfO2 dielectric
film.
Inventors: |
Hong; Kwon; (Kyoungki-do,
KR) ; Kil; Deok Sin; (Kyoungki-do, KR) |
Correspondence
Address: |
LADAS & PARRY LLP
224 SOUTH MICHIGAN AVENUE
SUITE 1600
CHICAGO
IL
60604
US
|
Family ID: |
36216002 |
Appl. No.: |
11/122834 |
Filed: |
May 5, 2005 |
Current U.S.
Class: |
438/396 ;
257/E21.008; 438/240; 438/253; 438/685; 438/785 |
Current CPC
Class: |
H01L 21/022 20130101;
H01L 21/3142 20130101; C23C 16/405 20130101; H01L 21/3141 20130101;
H01L 28/40 20130101; H01L 21/0228 20130101; H01L 21/02178 20130101;
H01L 21/02181 20130101; H01L 21/02194 20130101; H01L 21/31645
20130101; C23C 16/45525 20130101 |
Class at
Publication: |
438/396 ;
438/240; 438/253; 438/685; 438/785 |
International
Class: |
H01L 21/8242 20060101
H01L021/8242; H01L 21/20 20060101 H01L021/20; H01L 21/44 20060101
H01L021/44 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 8, 2004 |
KR |
10-2004-0090413 |
Claims
1. A method for forming a capacitor of semiconductor device, the
method comprising the steps of: forming a storage electrode
consisting of TiN on a semiconductor substrate; successively
depositing on the storage electrode a first HfO2 film, an HfxAlyOz
film wherein each of x, v, and z is greater than zero, and a second
HfO2 film using Atomic layer Deposition ALD) processes to form an
HfO2/HfxAlyOz/HfO2 dielectric film; and forming a plate electrode
consisting of TIN on the HfO2/HfxAlyOz/HfO2 dielectric film.
2. The method as claimed in claim 1, wherein the storage electrode
and the plate electrode are deposited with a thickness of 50 to 300
.ANG., respectively.
3. The method as claimed in claim 1, wherein the first and second
HfO2 films are deposited with a thickness of 30 to 80 .ANG.,
respectively.
4. The method as claimed in claim 1, wherein the HfxAlyOz film is
deposited with a thickness of 5 to 15 .ANG..
5. The method as claimed in claim 1 or 4, wherein the HfxAlyOz film
and is deposited by performing a first deposition cycle, in which
Hf source gas flowing, N2 purging, O3 gas flowing and N2 purging
progress successively, and a second deposition cycle, in which Al
source gas flowing, N2 purging, O3 gas flowing and N2 purging
progress successively, in the ration of 1:1 to 9:1.
6. A method for forming a capacitor of a semiconductor device, the
method comprising the steps of: forming a storage electrode
consisting of TiN on a semiconductor substrate; successively
depositing on the storage electrode a first HfxAlyOz film wherein
each of x, v, and z is greater than zero, an HfO2 film, and a
second HfxAlyOz film wherein each of x, v, and z is greater than
zero En using Atomic layer Deposition (ALD) processes to form an
HfO2/HfxAlyOz/HfO2 dielectric film; and forming a plate electrode
consisting of TiN on the HfO21 HfxAlyOz/HfO2 dielectric film.
7. The method as claimed in claim 6, wherein the storage electrode
and the plate electrode are deposited with a thickness of 50 to 300
.ANG., respectively.
8. The method as claimed in claim 6, wherein the HfO2 film is
deposited with a thickness of 20 to 60 .ANG..
9. The method as claimed in claim 6, wherein the first and second
HfxAlyOz films are deposited with a thickness of 5 to 15 .ANG.,
respectively.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to a method for
forming a capacitor of a semiconductor device, and more
particularly to a method for forming a capacitor of a semiconductor
device, which can improve a leakage current characteristic of HfO2
applied as a dielectric film of the capacitor by suppressing
low-temperature crystallization thereof.
[0003] 2. Description of the Prior Art
[0004] Recently, cells of a DRAM device has occupied a smaller area
with increase in a degree of integration of the DRAM device, so it
becomes more and more difficult to ensure charging capacity
required. As is well known in the art, the charging capacity of a
capacitor is proportional to an area of an electrode and a
dielectric constant of a dielectric film, and is inversely
proportional to a distance between electrodes, that is, a thickness
of the dielectric film. For ensuring charging capacity required,
therefore, it is necessary to reduce the thickness of the
dielectric film or to apply materials having a large dielectric
constant as the dielectric film.
[0005] Thereupon, in order to ensure charging capacity required,
researches are being vigorously pursued to replace the existing
Oxide-Nitride-Oxide (ONO) dielectric film by a single dielectric
film of Al2O3 (.epsilon.=9), a single dielectric film of HfO2
(.epsilon.=20) or a dual dielectric film of simply laminated
HfO2/Al2O3.
[0006] However, Al2O3 has a restriction on ensuring charging
capacity because its dielectric constant is not so different from
that of the existing Si3N4 material (.epsilon.=7), and HfO2 has a
poor leakage current characteristic caused by a low crystallization
temperature although it has a large dielectric constant. The dual
dielectric film of HfO2/Al2O3 also has a limitation on reducing an
equivalent oxide thickness (EOT; Tox) due to the small dielectric
constant of Al2O3.
[0007] In the end, the single dielectric film structure of Al2O3 or
HfO2 and the dual dielectric film structure of HfO2/Al2O3 may
ensure charging capacity required for a capacitor of a highly
integrated device such as a 65 nm-grade device, but cannot satisfy
the leakage current characteristic of the capacitor. Consequently,
the development of a dielectric film applicable to the 65 nm-grade
device must be settled without delay.
SUMMARY OF THE INVENTION
[0008] Accordingly, the present invention has been made to solve
the above-mentioned problem occurring in the prior art, and an
object of the present invention is to provide a method for forming
a capacitor of a semiconductor device, in which HfO2 is applied as
a dielectric film of the capacitor while increase of a leakage
current due to a low crystallization temperature of HfO2 can be
prevented.
[0009] A further object of the present invention is to provide a
method for forming a capacitor of a semiconductor device, in which
not only desired charging capacity can be secured by applying HfO2
as a dielectric film of the capacitor, but also an excellent
leakage current characteristic can be ensured.
[0010] In order to accomplish these objects, there is provided a
method for forming a capacitor of semiconductor device in
accordance with one aspect of the present invention, the method
comprising the steps of: forming a storage electrode consisting of
TiN on a semiconductor substrate; successively depositing a first
HfO2 thin film, an HfxAlyOz thin film and a second HfO2 thin film
on the storage electrode using Atomic layer Deposition (ALD)
processes to form an HfO2/HfxAlyOz/HfO2 dielectric film; and
forming a plate electrode consisting of TiN on the
HfO2/HfxAlyOz/HfO2 dielectric film.
[0011] Here, the storage electrode and the plate electrode are
deposited with a thickness of 50 to 300 .ANG., respectively.
[0012] Also, the first and second HfO2 thin films are deposited
with a thickness of 30 to 80 .ANG., respectively.
[0013] The HfxAlyOz thin film is deposited with a thickness of 5 to
15 .ANG., and is deposited by performing a first deposition cycle,
in which Hf source gas flowing, N2 purging, O3 gas flowing and N2
purging progress successively, and a second deposition cycle, in
which Al source gas flowing, N2 purging, O3 gas flowing and N2
purging progress successively, in the ratio of 1:1 to 9:1.
[0014] In accordance with another aspect of the present invention,
the above-mentioned objects are achieved by providing a method for
forming a capacitor of a semiconductor device, the method
comprising the steps of: forming a storage electrode consisting of
TiN on a semiconductor substrate; successively depositing a first
HfxAlyOz thin film, an HfO2 thin film and a second HfxAlyOz thin
film on the storage electrode using Atomic layer Deposition (ALD)
processes to form an HfxAlyOz/HfO2/HfxAlyOz dielectric film; and
forming a plate electrode consisting of TiN on the
HfxAlyOz/HfO2/HfxAlyOz dielectric film.
[0015] Here, the storage electrode and the plate electrode are
deposited with a thickness of 50 to 300 .ANG., respectively.
[0016] Also, the HfO2 thin film is deposited with a thickness of 20
to 60 .ANG..
[0017] The first and second HfxAlyOz thin films are deposited with
a thickness of 5 to 15 .ANG., respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other objects, features and advantages of the
present invention will be more apparent from the following detailed
description taken in conjunction with the accompanying drawings, in
which:
[0019] FIGS. 1a to 1c are process-by-process sectional views for
explaining a method for forming a capacitor in accordance with a
preferred embodiment of the present invention; and
[0020] FIG. 2 is a sectional view of a capacitor formed by a
forming method in accordance with another preferred embodiment of
the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Hereinafter, preferred embodiments of the present invention
will be described with reference to the accompanying drawings. In
the following description and drawings, the same reference numerals
are used to designate the same or similar components, and so
repetition of the description on the same or similar components
will be omitted.
[0022] In a method for forming a capacitor of a semiconductor
device according to the present invention, a dielectric film of the
capacitor essentially consists of HfO2. However, in contrast with a
conventional single or dual dielectric film, an HfxAlyOz thin film
having a larger dielectric constant than that of Al2O3 is
interposed between HfO2 thin films during the deposition of the
HfO2 thin films to form the dielectric film in a triple structure
of HfO2/HfxAlyOz/HfO2.
[0023] In connection with interposing the HfxAlyOz thin film
dielectric constant of which is larger than that of Al2O3 between
the HfO2 thin films, the dielectric film of the present invention
can reduce an equivalent oxide thickness (Tox) more than in the
conventional dual dielectric film structure and thus ensure
charging capacity required. In particular, since the HfxAlyOz thin
film suppresses the crystallization of HfO2, the dielectric film of
the present invention can improve the problem of a leakage current
caused by a low crystallization temperature when HfO2 is used as
the dielectric film.
[0024] Accordingly, the HfO2/HfxAlyOz/HfO2 dielectric film
according to the present invention makes it possible to manufacture
a capacitor which has charging capacity and a leakage
characteristic required for a 65 nm-grade device.
[0025] FIGS. 1 a to 1c illustrate process-by-process sectional
views for explaining a method for forming a capacitor of a
semiconductor device in accordance with a preferred embodiment of
the present invention, for which a description will be given below
in detail.
[0026] Referring to FIG. 1a, TiN is deposited on a semiconductor
device 11, which is formed with sub patterns including transistors
and bit lines, to form a storage electrode 12 consisting of TiN. At
this time, TiN is deposited with a thickness of 50 to 300 .ANG.
according to an Atomic layer Deposition (ALD) technique or a
Chemical Vapor Deposition (CVD) technique. Although FIG. 1
represents that the storage electrode 12 has a simple flat
plate-like structure, the storage electrode 12 may be formed in a
three-dimensional structure such as a concave structure and a
cylindrical structure.
[0027] Referring to FIG. 1b, a first HfO2 thin film 13a, an
HfxAlyOz thin film 13b and a second HfO2 thin film 13c are
successively deposited on the storage electrode 12 to form an
HfO2/HfxAlyOz/HfO2 dielectric film 13. At this time, each of the
first and second HfO2 thin films 13a, 13c is deposited by
repeatedly performing a deposition cycle, in which Hf source gas
flowing, N2 purging, O3 gas flowing and N2 purging progress
successively, according to an ALD technique until its desired
thickness is obtained. The HfxAlyOz thin film 13b is deposited by
repeatedly performing a first deposition cycle, in which Hf source
gas flowing, N2 purging, O3 gas flowing and N2 purging progress
successively, and a second deposition cycle, in which Al source gas
flowing, N2 purging, O3 gas flowing and N2 purging progress
successively, the number of times desired for each cycle. For
example, the first and second HfO2 thin films 13a, 13c are
deposited with a thickness of 30 to 80 .ANG., respectively. The
HfxAlyOz thin film 13b is deposited with a thickness of 5 to 15
.ANG. by performing the first and second deposition cycles in the
ratio of 1:1 to 9:1.
[0028] Referring to FIG. 1c, TiN having a thickness of 20 to 300
.ANG. is deposited on the HfO2/HfxAlyOz/HfO2 dielectric film 13
according to an ALD or CVD technique. In this way, the formation of
an MIM structure capacitor 10 in accordance with the present
invention is completed.
[0029] In the so-formed capacitor of the present invention, since
the HfxAlyOz thin film is interposed between the HfO2 thin films, a
large dielectric constant of HfO2 can be utilized to the maximum
extent possible and thus desired charging capacity can be ensured.
In addition, the HfxAlyOz thin film suppresses low-temperature
crystallization of HfO2, so that a leakage current characteristic
of the capacitor can be improved.
[0030] In the above-mentioned embodiment, the dielectric film is
formed in a triple structure of HfO2/HfxAlyOz/HfO2. In contrast
with this embodiment, when a first HfxAlyOz thin film 23a and a
second HfxAlyOz thin film 23c are deposited before and after the
deposition of a HfO2 thin film 23b, that is, the first HfxAlyOz
thin film 23a, the HfO2 thin film and the second HfxAlyOz thin film
23c are successively deposited to form a dielectric film 23 in a
triple structure of HfxAlyOz/HfO2/HfxAlyOz as shown in FIG. 2
illustrating another preferred embodiment of the present invention,
a capacitor 20 having the same characteristics as those of the
capacitor according to the above-mentioned embodiment can be
manufactured.
[0031] In FIG. 2, unexplained reference numerals `21`, `22` and
`24` designate the semiconductor substrate, the TiN storage
electrode and the TiN plate electrode, respectively.
[0032] As described above, in the method for forming a capacitor
according to the present invention, HfO2 is used as a dielectric
film while an HfxAlyOz thin film is used for complementing a
leakage current problem due to a low crystallization temperature of
HfO2, so that an excellent leakage current characteristic and large
charging capacity can be obtained even when the capacitor has a
small physical thickness. Consequently, it is possible to realize a
capacitor applicable to a 65 nm-grade device, which has a
dielectric film with a small equivalent oxide thickness and a low
leakage current.
[0033] Although preferred embodiments of the present invention have
been described for illustrative purposes, those skilled in the art
will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *