US 11,695,065 B2
Semiconductor device and method of manufacturing semiconductor device
Ze Chen, Tokyo (JP)
Assigned to Mitsubishi Electric Corporation, Tokyo (JP)
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
Filed on May 17, 2021, as Appl. No. 17/322,770.
Claims priority of application No. 2020-139278 (JP), filed on Aug. 20, 2020.
Prior Publication US 2022/0059680 A1, Feb. 24, 2022
Int. Cl. H01L 29/739 (2006.01); H01L 29/06 (2006.01); H01L 21/265 (2006.01); H01L 29/66 (2006.01)
CPC H01L 29/7397 (2013.01) [H01L 21/265 (2013.01); H01L 29/0615 (2013.01); H01L 29/66348 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A semiconductor device comprising:
a semiconductor substrate having a drift layer of a first conductivity type between a first main surface and a second main surface opposite to the first main surface;
a first buffer layer of the first conductive type provided between the drift layer and the second main surface in contact with the drift layer, having a resistivity lower than that of the drift layer, and having an impurity concentration higher than that of the drift layer; and
a high resistivity layer provided between the first buffer layer and the second main surface and having a resistivity higher than that of the drift layer, wherein
impurities of the first conductivity type of the first buffer layer are protons.