US 12,336,224 B2
Semiconductor device and method for manufacturing the same
Hiromichi Godo, Kanagawa (JP); and Tetsuhiro Tanaka, Kanagawa (JP)
Assigned to Semiconductor Energy Laboratory Co., Ltd., Kanagawa-ken (JP)
Filed by SEMICONDUCTOR ENERGY LABORATORY CO., LTD., Atsugi (JP)
Filed on Jun. 2, 2022, as Appl. No. 17/830,620.
Application 14/620,403 is a division of application No. 13/674,175, filed on Nov. 12, 2012, granted, now 8,962,386, issued on Feb. 24, 2015.
Application 17/830,620 is a continuation of application No. 16/038,515, filed on Jul. 18, 2018, abandoned.
Application 16/038,515 is a continuation of application No. 14/620,403, filed on Feb. 12, 2015, abandoned.
Claims priority of application No. 2011-257487 (JP), filed on Nov. 25, 2011.
Prior Publication US 2022/0302314 A1, Sep. 22, 2022
Int. Cl. H10D 30/67 (2025.01); H01L 21/02 (2006.01)
CPC H10D 30/6755 (2025.01) [H10D 30/6739 (2025.01); H01L 21/02554 (2013.01); H01L 21/02565 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A semiconductor device comprising:
a gate electrode; and
an oxide semiconductor film overlapping with the gate electrode with a gate insulating film therebetween,
wherein the gate electrode comprises:
a first layer in contact with the gate insulating film;
a second layer under the first layer; and
a third layer under the second layer,
wherein the first layer and the third layer overlap with each other with the second layer provided therebetween,
wherein the first layer is in direct contact with a top surface and side surfaces of the second layer,
wherein each of the first layer and the second layer comprises a first metal element and oxygen,
wherein the first layer has an oxygen concentration lower than that of the second layer,
wherein the third layer has a conductivity higher than that of each of the first layer and the second layer, and
wherein the oxide semiconductor film comprises In, Zn, and Ga.