Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – On insulating substrate or layer
Reexamination Certificate
1999-04-05
2001-08-28
Chaudhuri, Olik (Department: 2814)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
On insulating substrate or layer
C438S162000, C438S308000
Reexamination Certificate
active
06281055
ABSTRACT:
This application claims the benefit of Korean Patent Application No. 1998-12205, filed on Apr. 7, 1998, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of fabricating a thin film transistor formed by doping an active layer with impurities by using a gate as a mask and by forming a source and a drain by activating the impurities.
2. Discussion of the Related Art
FIGS. 1A-1C
show cross-sectional views of a TFT structure which illustrates a method for fabricating a thin film transistor (hereinafter abbreviated TFT) according to a related art.
In
FIG. 1A
, an insulating or buffer layer
13
is formed by depositing an insulating substance, such as silicon dioxide, on a transparent substrate
11
, such as a glass substrate or the like, with Chemical Vapor Deposition (hereinafter abbreviated CVD). An active layer
15
is formed by depositing polycrystalline silicon on the buffer layer
13
with CVD. Next, the active layer
15
is patterned by photolithography to be etched on a predetermined portion of the buffer layer
13
.
According to
FIG. 1B
, another layer of silicon dioxide is now grown or deposited across the surface of the silicon wafer. Using similar lithographic techniques to those described above, holes are etched through the silicon dioxide in areas in which it is desired to make the connections and metallization layer of aluminum interconnections are deposited. In other words, after the silicon dioxide layer covers the active layer
15
, a conductive material such as Aluminum, metal, or the like is deposited on the silicon dioxide layer by the CVD process.
A gate insulating layer
17
and a gate
19
are formed by patterning the conductive material and the silicon dioxide layer by photolithography so that they remain over a selected portion of the active layer
15
.
Subsequently, ion-implanted region
21
, constituting source and drain regions, is formed by heavily doping an exposed surface of the active layer
15
with impurities such as Phosphorous (P), Arsenic (AS), or the like, by using the gate
19
as a mask.
Referring to
FIG. 1C
, the impurities implanted in the ion-implanted region
21
are activated by application of a laser beam onto the region
21
. Consequently, an impurity region
23
constituting a source and a drain is formed as the impurity ions in the region
21
are activated by the laser beam.
However, as the above-described method of fabricating a TFT according to the related art reveals, this process involves complicated steps, such as irradiation of the impurity region with a laser beam to form a source and a drain region and activation of the implanted impurity ions.
The use of laser beams are costly, not very feasible, and can significantly increase the risk of structural damage to the semiconductor layers because of its heat treatment intensity.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method of fabricating a thin film transistor that substantially obviates one or more of the problems due to the limitations and disadvantages of the related art.
The object of the present invention is to provide a method of fabricating a TFT including the step of simultaneously forming an impurity region for a source and a drain region and the step of implanting and activating the impurity ions in such impurity region.
Additional features and advantages of the invention will be set forth in the description which follows and in part become 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 of fabricating a thin film transistor comprises the steps of forming a gate insulating layer on the active layer; forming a gate on the gate insulating layer; forming an excited region in an exposed portion of the active layer by implanting hydrogen ions to the active layer by using the gate as a mask; and forming an impurity region by heavily implanting impurity ions to said excited region while the excited region remains in an excited state.
It is understood that 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:
patent: 5512494 (1996-04-01), Tanabe
patent: 5620906 (1997-04-01), Yamaguchi et al.
patent: 5897346 (1999-04-01), Yamaguchi et al.
patent: 5956581 (1999-09-01), Yamazaki et al.
Chaudhuri Olik
LG.Philips LCD Co. , Ltd.
Long Aldridge & Norman LLP
Rao Shrinivas H.
LandOfFree
Method of fabricating a thin film transistor 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 fabricating a thin film transistor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of fabricating a thin film transistor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2548886