Method for fabricating thin film at high temperature

Details Method for fabricating thin film at high temperature Method for fabricating thin film at high temperature

2000-03-13

2001-06-26

Pham, Long (Department: 2823)

Semiconductor device manufacturing: process

Coating with electrically or thermally conductive material

To form ohmic contact to semiconductive material

C438S682000, C438S685000

Reexamination Certificate

active

06251780

ABSTRACT:

This application claims the benefit of Korean Application No. 22578/1999 filed on Jun. 16, 1999, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for fabricating a semiconductor device, and more particularly, to a method for fabricating a semiconductor device, which is suitable to form a thin film that is stable at a high temperature.
2. Discussion of the Related Art
As semiconductor devices become smaller from 0.25 micron class to 0.18 and 0.13 micron classes, their sheet resistivity increases and becomes a problem. In order to solve this problem, presently cobalt silicide is widely used which shows a lower resistance than titanium silicide in a micron pattern.
A related art method for fabricating a semiconductor device will be explained with reference to the attached drawings. FIGS.
1
A~
1
D illustrate steps of a related art method for fabricating a semiconductor device.
Referring to
FIG. 1A
, a field oxide film
12
is formed on a field region of a semiconductor substrate
11
having the field region and an active region defined thereon. A gate insulating film
13
and a gate electrode polysilicon film (not shown) are formed in succession on an entire surface of the semiconductor substrate
11
, and subjected to photolithography and etching, to remove the polysilicon film and the gate insulating film
13
selectively and form a gate electrode
14
. The gate electrode
14
is used as a mask in implanting impurity ions in the entire surface of the semiconductor substrate
11
lightly, to form LDD (Lightly Doped Drain) regions
15
in the surface of the semiconductor substrate
11
on both sides of the gate electrode
14
.
As shown in
FIG. 1B
, an insulating film is formed on an entire surface of the semiconductor substrate
11
inclusive of the gate electrode
14
. The insulating film is then etched back to form insulating sidewalls
16
at both sides of the gate electrode
14
. Then, the gate electrode
14
and the insulating film sidewalls
16
are used as masks in implanting source/drain impurity ions (As
+
or P
+
) in an entire surface of the semiconductor substrate
11
heavily, to form source/drain impurity regions
17
in the surface of the semiconductor substrate
11
on both sides of the gate electrode
14
connected to the LDD regions
15
.
As shown in
FIG. 1C
, a cobalt film
18
and a titanium nitride film TiN
19
are formed on an entire surface of the semiconductor substrate
11
in succession, and, as shown in
FIG. 1D
, subjected to annealing at approximately 500° C., to cause reaction between the cobalt film
18
, the gate electrode
14
and the semiconductor substrate
11
, thus forming a cobalt silicide film
20
. In this instance, the titanium nitride
19
is provided for blocking an influence from oxygen when the cobalt reacts with the silicon by annealing. The titanium nitride film
19
is in general formed in-situ without vacuum break after the formation of the cobalt film
18
. The titanium nitride film
19
and the remaining cobalt film
18
, which both had no reaction with the semiconductor substrate
11
and the gate electrode
14
, are wet etched and removed using a mixed solution of H
2
SO
4
:H
2
O
2
or NH
4
OH:H
2
O
2
and a mixed solution of HCL:H
2
O
2
:H
2
O, and subjected to annealing at approximately 700~800° C., to lower a resistance of the cobalt silicide film
20
. The annealings are conducted at a low temperature for the first time and at a high temperature for the second time in formation of the cobalt silicide film
20
to form a cobalt silicide film
20
with a low resistance because the high temperature annealing forms the cobalt silicide film even at sides of the insulating film sidewalls
16
.
However, the related art method for fabricating a semiconductor device has the following problems.
First, the formation of the cobalt silicide film by annealing consumes the substrate excessively, and partial excessive formation of the cobalt silicide film causes an excessive flow of leakage current at a shallow junction that is inevitable when devices are scaled down.
Second, the titanium nitride film only blocks an influence from oxygen, but can not prevent the consumption of the substrate caused by cobalt.
Third, a thin film of cobalt silicide, formed by forming a cobalt film on a polysilicon film of fine grain size and subjecting to annealing, is unstable and susceptible to heat because cobalt atoms can migrate to a lower portion of the polysilicon film along grain boundaries of the polysilicon film.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method for fabricating a semiconductor device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a method for fabricating a semiconductor device, which can form a thin film that is stable at a high temperature.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the method for fabricating a semiconductor device includes the steps of (1) forming a refractory metal film on a semiconductor substrate, (2) forming a capping film on the refractory metal film, (3) injecting IV group atoms into the capping film, to knock on atoms of the capping film into the refractory metal film, and (4) forming a metal silicide film at an interface between the semiconductor substrate and the refractory metal film.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.


REFERENCES:
Derwent-ACC-No: 1985-047514, 06/83.

Affiliated with

Also associated with

Rating

Method for fabricating thin film at high temperature does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method for fabricating thin film at high temperature, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for fabricating thin film at high temperature will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2464246