[54] METHOD OF MANUFACTURING A THIN FILM TRANSISTOR IN WHICH THE GATE INSULATOR COMPRISES TWO OXIDE FILMS
[75] Inventors: Hiroki Adachi; Akira Takenouchi;
Takeshi Fukada; Hiroshi Uehara:
Yasuhiko Takemura, all of Kanagawa.
Japan
[73] Assignee: Semiconductor Energy Laboratory
Co., Ltd., Kanagawa, Japan
[21] Appl. No.: 280,461
[22] Filed: Jul. 26,1994
[30] Foreign Application Priority Data
Jul. 27, 1993 [JP] Japan 5-204773
Aug. 27, 1993 [JP] Japan 5-235463
[51] IntCl.6 H01L 21/336
[52] U.S. CI 438/151; 438/166; 438/591;
438/762
[58] Field of Search 437/40 TFT, 41 TFT,
437/21, 101, 239, 238, 235, 233, 42
[56] References Cited
U.S. PATENT DOCUMENTS 4,675,978 6/1987 Swartz 437/21
A method for manufacturing a semiconductor device comprises the steps of forming a semiconductor film on a substrate, oxidizing a surface of said semiconductor film in an oxidizing atmosphere with said semiconductor film heated or irradiated with light, and further depositing an oxide film on the oxidized surface of the semiconductor film by PVD or CVD. The first oxide film has a good interface condition with the semiconductor film and a characteristics of an insulated gate field effect transistor can be improved if the first oxide film and the second oxide film are used as a gate insulating film.
14 Claims, 10 Drawing Sheets
