US 9,812,544 B2
Semiconductor device and manufacturing method thereof
Yuta Endo, Kanagawa (JP); Toshinari Sasaki, Kanagawa (JP); Kosei Noda, Kanagawa (JP); Hitomi Sato, Kanagawa (JP); and Yuhei Sato, Kanagawa (JP)
Assigned to Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken (JP)
Filed by Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken (JP)
Filed on Nov. 9, 2015, as Appl. No. 14/935,553.
Application 14/935,553 is a division of application No. 13/316,604, filed on Dec. 12, 2011, granted, now 9,202,822.
Claims priority of application No. 2010-282166 (JP), filed on Dec. 17, 2010.
Prior Publication US 2016/0064505 A1, Mar. 3, 2016
Int. Cl. H01L 29/49 (2006.01); H01L 27/12 (2006.01); H01L 29/786 (2006.01); H01L 21/28 (2006.01); H01L 21/288 (2006.01); H01L 29/423 (2006.01); H01L 29/66 (2006.01)
CPC H01L 29/4908 (2013.01) [H01L 21/288 (2013.01); H01L 21/28088 (2013.01); H01L 27/1225 (2013.01); H01L 29/42384 (2013.01); H01L 29/66742 (2013.01); H01L 29/7869 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for manufacturing a semiconductor device comprising:
forming an oxide semiconductor film over a substrate;
forming a gate insulating film over the oxide semiconductor film; and
forming a gate electrode including a tungsten oxide film by a sputtering method over the gate insulating film,
wherein a work function of the gate electrode is higher than or equal to 4.9 eV and lower than or equal to 5.6 eV,
wherein a thickness of the gate electrode is greater than or equal to 10 nm.