US 12,224,355 B2
Semiconductor device and manufacturing method thereof
Shunpei Yamazaki, Setagaya (JP); Junichiro Sakata, Atsugi (JP); and Jun Koyama, Sagamihara (JP)
Assigned to Semiconductor Energy Laboratory Co., Ltd., Atsugi (JP)
Filed by Semiconductor Energy Laboratory Co., Ltd., Atsugi (JP)
Filed on Nov. 8, 2023, as Appl. No. 18/504,297.
Application 18/504,297 is a continuation of application No. 17/367,689, filed on Jul. 6, 2021, granted, now 11,817,506.
Application 17/367,689 is a continuation of application No. 16/789,872, filed on Feb. 13, 2020, abandoned.
Application 16/789,872 is a continuation of application No. 15/651,251, filed on Jul. 17, 2017, abandoned.
Application 15/651,251 is a continuation of application No. 14/849,928, filed on Sep. 10, 2015, granted, now 9,711,651, issued on Jul. 18, 2017.
Application 14/849,928 is a continuation of application No. 13/104,546, filed on May 10, 2011, granted, now 9,136,390, issued on Sep. 15, 2015.
Application 13/104,546 is a continuation of application No. 12/646,085, filed on Dec. 23, 2009, granted, now 8,222,092, issued on Jul. 17, 2012.
Claims priority of application No. 2008-333788 (JP), filed on Dec. 26, 2008.
Prior Publication US 2024/0072176 A1, Feb. 29, 2024
Int. Cl. H01L 29/786 (2006.01); H01L 21/02 (2006.01); H01L 27/12 (2006.01); H01L 29/24 (2006.01); H01L 29/66 (2006.01)
CPC H01L 29/7869 (2013.01) [H01L 27/1225 (2013.01); H01L 27/124 (2013.01); H01L 29/24 (2013.01); H01L 29/66969 (2013.01); H01L 29/78696 (2013.01); H01L 21/02554 (2013.01); H01L 21/02565 (2013.01); H01L 21/02631 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A semiconductor device comprising a transistor comprising:
a first conductive layer;
a first metal oxide layer having a region provided over the first conductive layer;
a second metal oxide layer having a region provided over the first metal oxide layer;
a third metal oxide layer having a region provided over a first region of the second metal oxide layer;
a fourth metal oxide layer having a region provided over a second region of the second metal oxide layer; and
a second conductive layer having a region provided over the third metal oxide layer, the second conductive layer electrically connected to the third metal oxide layer,
wherein the second metal oxide layer comprises a depression part between the first region and the second region,
wherein the depression part of the second metal oxide layer is in contact with an insulating layer provided over the second metal oxide layer,
wherein a conductivity of the first metal oxide layer is higher than a conductivity of the second metal oxide layer,
wherein each of a conductivity of the third metal oxide layer and a conductivity of the fourth metal oxide layer is higher than the conductivity of the second metal oxide layer, and
wherein an end portion of the second metal oxide layer has a shape with a lower part protruding from an upper part.