US 11,996,449 B2
Semiconductor device with carbon-density-decreasing region
Tsunenobu Kimoto, Kyoto (JP); Takuma Kobayashi, Kyoto (JP); Yuki Nakano, Kyoto (JP); and Masatoshi Aketa, Kyoto (JP)
Assigned to ROHM CO., LTD., Kyoto (JP)
Filed by ROHM CO., LTD., Kyoto (JP)
Filed on Sep. 28, 2022, as Appl. No. 17/955,067.
Application 17/955,067 is a continuation of application No. 16/962,160, granted, now 11,502,172, previously published as PCT/JP2019/000540, filed on Jan. 10, 2019.
Claims priority of application No. 2018-005735 (JP), filed on Jan. 17, 2018.
Prior Publication US 2023/0019556 A1, Jan. 19, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 29/16 (2006.01); H01L 21/02 (2006.01); H01L 21/285 (2006.01); H01L 29/06 (2006.01); H01L 29/423 (2006.01); H01L 29/66 (2006.01)
CPC H01L 29/1608 (2013.01) [H01L 21/02238 (2013.01); H01L 21/02614 (2013.01); H01L 21/28556 (2013.01); H01L 29/0607 (2013.01); H01L 29/4236 (2013.01); H01L 29/66045 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A semiconductor device comprising:
an SiC semiconductor layer of a first conductivity type;
a plurality of body regions of a second conductivity type that are formed in a surface layer portion of the SiC semiconductor layer;
a plurality of source regions of the first conductivity type that are formed in surface layer portions of the body regions, respectively;
an SiO2 layer that covers the SiC semiconductor layer such as to straddle the plurality of adjacent source regions, and that has a connection surface in contact with the SiC semiconductor layer and a non-connection surface positioned on an opposite side to the connection surface;
a gate electrode that is arranged on the non-connection surface of the SiO2 layer such as to expose a part of the non-connection surface;
an interlayer insulating layer that covers an exposed portion of the non-connection surface of the SiO2 layer and the gate electrode; and
an interfacial region that is formed in a region between the SiC semiconductor layer and the SiO2 layer, and that has an interface state density that is 4.0×1011 eV−1·cm−2 or less in a range in which an energy level from a conduction band edge is not less than 0.2 eV and not more than 0.5 eV,
wherein the SiO2 layer has:
a carbon-density-decreasing region that is formed in a region on the connection surface side and in which a carbon density gradually decreases from the connection surface to the non-connection surface; and
a low carbon density region that is formed in a region on the non-connection surface side with respect to the carbon-density-decreasing region and that has a carbon density lower than a carbon density of the carbon-density-decreasing region.