Method of selective epitaxial growth for semiconductor devices

Details Method of selective epitaxial growth for semiconductor devices Method of selective epitaxial growth for semiconductor devices

2001-12-28

2003-04-01

Ghyka, Alexander (Department: 2812)

Semiconductor device manufacturing: process

Formation of semiconductive active region on any substrate

On insulating substrate or layer

C438S416000, C438S429000, C438S481000

Reexamination Certificate

active

06541355

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method of fabricating a semiconductor device. More particularly, the present invention relates to a method of selective epitaxial growth (SEG) having improved selectivity.
2. Description of the Prior Art
Typical selective epitaxial growth is a useful technology applied to selectively grow a homogeneous or heterogeneous semiconductor layer on only an exposed semiconductor surface, and omitting epitaxial growth over a masked surface on an insulating layer, such as an oxide layer or a nitride layer.
Recently, various ways to obtain selective epitaxial growth of silicon or silicon germanium have been introduced in the art. Among them, an ultrahigh vacuum chemical vapor deposition (UHVCVD) technique has attracted considerable attention because it enables selective epitaxial growth at a low temperature, often at less than 800° C. The UHVCVD technique employs mostly SiH
4
, Si
2
H
6
, GeH
4
or Ge
2
H
6
as a source gas, and Cl
2
as a selectivity promoting gas.
On the other hand, the selective epitaxial growth technology is classified into either of two types, conventional growth and cyclical growth.
Conventional growth is a technique to grow an epitaxial silicon layer or an epitaxial silicon germanium layer by simultaneously supplying a source gas, such as SiH
4
, Si
2
H
6
, GeH
4
and Ge
2
H
6
, and Cl
2
gas into a reactor.
Cyclical growth is a technique to alternatively supply the source gas and Cl
2
gas at alternating times in the manner shown in FIG.
1
. Here, Cl
2
gas serves to prevent the nucleus generation of polysilicon or silicon germanium on surfaces of the insulating layer due to either etching action or surface passivation.
Therefore, as illustrated in
FIG. 2
, the increase in a flow rate of Cl
2
gas generally improves the selectivity of epitaxial growth.
Nevertheless, a high flow rate of Cl
2
gas during selective epitaxial growth not only reduces the growth rate of the epitaxial layer, as depicted in
FIG. 3
, but also detrimentally affects the expected life span of the processing facilities. For at least the above reasons, there is a need to minimize the use of Cl
2
gas.
After using a conventional method of selective epitaxial growth, a photograph of
FIG. 4
shows an experimental result under conditions of Si
2
H
6
source gas supplied with a flow rate of 10 sccm for about ten seconds in a first step and then Cl
2
gas supplied with a flow rate of 2 sccm for about twelve seconds in a second step. Here the epitaxial growth is made on a semiconductor substrate having a nitride layer at a temperature of about 750° C.
As shown in
FIG. 4
, a polysilicon layer is grown on the nitride layer; therefore the desired selectivity is not obtained. That is, since the nucleus of polysilicon or silicon germanium is generated first of all at a defective site on the surface of the insulating layer during a low temperature epitaxial growth less than 800° C., the epitaxial growth is not selective.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method of selective epitaxial growth for a semiconductor device, capable of guaranteeing selectivity of the epitaxial growth and further preventing degradation of a gate oxide layer.
Another object of the present invention is to provide a method of selective epitaxial growth for a semiconductor device, allowing an improvement in productivity by increasing the growth rate of the epitaxial layer.
These and other objects in accordance with the present invention are attained by a method of selective epitaxial growth for a semiconductor device, the method comprising the steps of loading a semiconductor substrate into a reaction chamber, wherein a mask layer is selectively formed on the semiconductor substrate to define a first portion exposed beyond the mask layer and a second portion covered with the mask layer; supplying a source gas into the reaction chamber so that the source gas is adsorbed on the first portion of the semiconductor substrate and thus a semiconductor epitaxial layer is selectively formed on the first portion; supplying a selectivity promoting gas, including H
2
gas, into the reaction chamber, whereby any nucleus of semiconductor material is removed from the surface of the mask layer of the semiconductor substrate and thus selectivity of the semiconductor epitaxial layer is improved; and sequentially repeating the steps of supplying the source gas and the selectivity promoting gas, whereby the semiconductor epitaxial layer is grown to a desired thickness.


REFERENCES:
patent: 4058430 (1977-11-01), Suntola et al.
patent: 4882294 (1989-11-01), Christenson
patent: 5073516 (1991-12-01), Moslehi
patent: 5273921 (1993-12-01), Neudeck et al.
patent: 5294286 (1994-03-01), Nishizawa et al.
patent: 5321306 (1994-06-01), Choi et al.
patent: 5423286 (1995-06-01), Yonehara et al.
patent: 5434092 (1995-07-01), Neudeck et al.
patent: 5604368 (1997-02-01), Taur et al.
patent: 5804470 (1998-09-01), Wollesen
patent: 5895948 (1999-04-01), Mori et al.
patent: 5955759 (1999-09-01), Ismail et al.
patent: 5963822 (1999-10-01), Saihara et al.
patent: 6030891 (2000-02-01), Tran et al.
patent: 6030894 (2000-02-01), Hada et al.
patent: 6090691 (2000-07-01), Ang et al.
patent: 6150190 (2000-11-01), Stankus et al.
patent: 59082768 (1984-05-01), None
patent: 59165461 (1984-09-01), None
patent: 59165462 (1984-09-01), None
patent: 59165463 (1984-09-01), None
patent: 59165464 (1984-09-01), None
patent: 59165465 (1984-09-01), None
patent: 59189677 (1984-10-01), None
patent: 61006195 (1986-01-01), None
patent: 63164355 (1988-07-01), None
patent: 02130919 (1990-05-01), None
patent: 02-130919 (1990-05-01), None
patent: 07130682 (1995-05-01), None
patent: 10107219 (1998-04-01), None

Affiliated with

Also associated with

Rating

Method of selective epitaxial growth for semiconductor devices 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 of selective epitaxial growth for semiconductor devices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of selective epitaxial growth for semiconductor devices will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3056709