Patent Number: 9,741,866

Title: Semiconductor device

Abstract: To provide a highly reliable semiconductor device which includes a transistor including an oxide semiconductor, in a semiconductor device including a staggered transistor having a bottom-gate structure provided over a glass substrate, a gate insulating film in which a first gate insulating film and a second gate insulating film, whose compositions are different from each other, are stacked in this order is provided over a gate electrode layer. Alternatively, in a staggered transistor having a bottom-gate structure, a protective insulating film is provided between a glass substrate and a gate electrode layer. A metal element contained in the glass substrate has a concentration lower than or equal to 5.times.10.sup.18 atoms/cm.sup.3 at the interface between the first gate insulating film and the second gate insulating film or the interface between the gate electrode layer and a gate insulating film.

Inventors: Cho; Takayuki (Tochigi, JP), Koshioka; Shunsuke (Tochigi, JP), Yokoyama; Masatoshi (Tochigi, JP), Yamazaki; Shunpei (Setagaya, JP)

Assignee: Semiconductor Energy Laboratory Co., Ltd.

International Classification: H01L 29/66 (20060101); H01L 29/786 (20060101); H01L 29/51 (20060101); H01L 29/49 (20060101)

Expiration Date: 2021-08-22 0:00:00