Method for producing insulated gate thin film semiconductor device

DETAILED DESCRIPTION The object of the present invention is to prevent such the deterioration, and to provide a method for producing an insulated gate semiconductor device having less deterioration.
According to a first aspect of the present invention, the following processes are obtained.
(1) An amorphous semiconductor film is etched into a first shape that a width of a narrowest portion is 100 .
mu.
m or less, to form an island semiconductor region.
(2) The semiconductor region is photo-annealed to crystalize it or to increase the crystallinity thereof.
(3) Of end portions (or peripheral portions) of the semiconductor region, at least a gate electrode or a channel forming region of a semiconductor device is etched by 10 .
mu.
m or more from ends, to form a semiconductor region having a second shape.
Also, according to a second aspect of the present invention, the following processes are obtained.
(1) An amorphous semiconductor film is etched into a first shame that a width of a narrowest portion is 100 .
mu.
m or less, to form an island semiconductor region.
(2) The semiconductor region is photo-annealed to crystalize it or to increase the crystallinity thereof.
(3) At least a part of end portions (or peripheral portions) of the semiconductor region is etched.
(4) An gate insulating film is formed to cover the semiconductor region.
(5) An gate electrode is formed across the etched portion of the end portions of the semiconductor region.
(6) An N-type or P-type impurity is introduced or diffused using the gate electrode as a mask.
In the first and second aspects of the present invention, the first shape is one of a rectangle, a regular polygon and an ellipse (including a circle), and generally it is preferred that a shape does not include a concave portion at any point on a periphery.
In the above structure, an amorphous silicon film is formed on a substrate having an insulating surface, such as a glass substrate or a quartz substrate by plasma chemical vapor deposition (plasma CVD) and low pressure thermal CVD