[54] SEMICONDUCTOR DEVICE AND METHOD FOR FORMING THE SAME
[75] Inventors: Shunpei Yamazaki, Tokyo; Hongyong Zhang; Yasuhiko Takemura, both of Kanagawa, all of Japan
[73] Assignee: Semiconductor Energy Laboratory Co., Ltd., Kanagawa-ken, Japan
[21] Appl. No.: 614,849
[22] Filed: Mar. 12,1996
Related U.S. Application Data
[60] Continuation of Ser. No. 262,335, Jun. 17,1994, abandoned, which is a division of Ser. No. 85,931, Jul. 6, 1993.
[30] Foreign Application Priority Data
Jul. 6, 1992 [JP] Japan 4-201932
Jul. 24, 1992 [JP] Japan 4-218324
Feb. 10, 1993 [JP] Japan 5-45786
[51] Int. CI.6 H01L 23/58
[52] U.S. CI 257/635; 257/66; 257/352;
257/353
[58] Field of Search 257/66, 352, 353,
257/354, 347, 635
[56] References Cited
U.S. PATENT DOCUMENTS
4,282,543 8/1981 Ihara et al 257/347
4,461,071 7/1984 Poleshuk 257/352
4,727,044 2/1988 Yamazaki.
4,851,363 7/1989 Troxell et al 257/349
4,876,582 10/1989 Janning 257/66
5,289,030 2/1994 Yamazaki et al 257/66
FOREIGN PATENT DOCUMENTS
0474289 3/1992 European Pat. Off. 257/66
62- 188373 8/1987 Japan 257/66
63- 258063 10/1988 Japan 257/347
Primary Examiner—Ngin V. Ngo
Attorney, Agent, or Firm—Sixbey, Friedman, Leedom & Ferguson, P.C.; Gerald J. Ferguson, Jr.
[57] ABSTRACT
Thin-film semiconductor devices such as TFTs (thin-film transistors) and methods of fabricating the same. TFTs are formed on an insulating substrate. First, a substantially amorphous semiconductor coating is formed on the substrate. A protective coating transparent to laser radiation is formed on the semiconductor coating. The laminate is irradiated with laser radiation to improve the crystallinity of the semiconductor coating. Then, the protective coating is removed to expose the surface of the semiconductor coating. A coating for forming a gate-insulating film is formed. Subsequently, gate electrodes are formed. Another method relates to fabrication of semiconductor devices such as TFTs on an insulating substrate. After forming a first coating consisting mainly of aluminum nitride, a second coating consisting principally of silicon oxide is formed. Semiconductor devices such as TFTs or semiconductor circuits are built on the second coating serving as a base layer.
26 Claims, 16 Drawing Sheets
