Claims
- 1. A top gate type thin film transistor comprising:
- a semiconductor island comprising a channel forming region, a source region and a drain region therein;
- a gate electrode formed over said channel forming region of the semiconductor island and extending across an edge of the semiconductor island;
- an insulator interposed between said gate electrode and said semiconductor island,
- wherein thickness of said insulator is larger on at least said edge of semiconductor island, and
- wherein a side portion of the semiconductor island is smoothly tapered, and a portion of the insulator comprises at least one layer.
- 2. A thin film transistor comprising:
- a semiconductor island comprising a channel forming region, a source region and a drain region therein;
- a gate electrode formed over said channel forming region of the semiconductor island and extending across an edge of the semiconductor island;
- a gate insulating film interposed between said gate electrode and said semiconductor island at least on said edge of the semiconductor island; and
- another insulating film interposed between said gate electrode and said semiconductor island at least on said edge of the semiconductor island,
- wherein a side portion of the semiconductor island is smoothly tapered, and
- wherein a total thickness of said gate insulating film and said another insulating film is larger on said edge of semiconductor island than on a middle portion of said semiconductor island.
- 3. The transistor of claim 2 wherein said gate insulating film is in contact with said channel forming region.
- 4. The transistor of claim 2 wherein a thickness of said side portion is monotonically decreased toward an end of said side portion.
- 5. The transistor of claim 2 wherein said gate insulating film and said another insulating film are both superposed on said edge of the semiconductor island.
- 6. A semiconductor device comprising:
- a semiconductor island, which is formed in contact with an undercoating insulating film formed over a substrate, having a tapered periphery;
- a gate electrode formed over said semiconductor island and extending across one edge of said semiconductor island;
- an insulator interposed between said gate electrode and said semiconductor island,
- wherein a thickness of said insulator is larger on said edge of the semiconductor island across which said gate electrode extends than on a middle portion of the semiconductor island, and
- wherein a side portion of the semiconductor island is smoothly tapered and over which a portion of the insulator comprises at least one layer.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3-340338 |
Nov 1991 |
JPX |
|
Parent Case Info
This is a divisional application of Ser. No. 07/979,261, filed Nov. 20, 1992, now U.S. Pat. No. 5,470,762.
US Referenced Citations (19)
Foreign Referenced Citations (6)
Number |
Date |
Country |
0405063 |
Jan 1991 |
EPX |
0513590 |
Nov 1992 |
EPX |
53-26584 |
Mar 1978 |
JPX |
55-68651 |
May 1980 |
JPX |
55-75238 |
Jun 1980 |
JPX |
1241859 |
Sep 1989 |
JPX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
979261 |
Nov 1992 |
|