US 12,256,569 B2
Silicon carbide MOSFET device and cell structure thereof
Yafei Wang, Hunan (CN); Xiaoping Dai, Hunan (CN); Chengzhan Li, Hunan (CN); and Yangang Wang, Hunan (CN)
Assigned to ZHUZHOU CRRC TIMES SEMICONDUCTOR CO., LTD., Zhuzhou (CN)
Appl. No. 17/774,853
Filed by ZHUZHOU CRRC TIMES SEMICONDUCTOR CO., LTD., Hunan (CN)
PCT Filed Dec. 25, 2019, PCT No. PCT/CN2019/128390
§ 371(c)(1), (2) Date May 5, 2022,
PCT Pub. No. WO2021/088232, PCT Pub. Date May 14, 2021.
Claims priority of application No. 201911089113.2 (CN), filed on Nov. 8, 2019.
Prior Publication US 2022/0406929 A1, Dec. 22, 2022
Int. Cl. H10D 84/00 (2025.01); H10D 30/66 (2025.01); H10D 62/10 (2025.01); H10D 62/17 (2025.01); H10D 62/832 (2025.01); H10D 64/27 (2025.01); H10D 64/64 (2025.01); H10D 84/80 (2025.01)
CPC H10D 84/146 (2025.01) [H10D 30/668 (2025.01); H10D 62/109 (2025.01); H10D 62/127 (2025.01); H10D 62/393 (2025.01); H10D 62/8325 (2025.01); H10D 64/512 (2025.01); H10D 84/811 (2025.01); H10D 62/106 (2025.01); H10D 64/64 (2025.01); H10D 84/00 (2025.01)] 9 Claims
OG exemplary drawing
 
1. A cell structure of a silicon carbide MOSFET device, comprising:
a first conductivity type drift region, which is located above a first conductivity type substrate;
a main trench, which is provided downwardly in a surface of the drift region, a Schottky metal being provided on surfaces of a bottom and sidewalls of the main trench;
a second conductivity type well region, which is located in the surface of the drift region and provided around the main trench;
a first conductivity type source region, which is located in a surface of the well region, wherein the source region is located at a side, close to the main trench, of the well region, but is not in contact with the main trench;
a gate structure, which is located at sides, close to the main trench, of the source region, the well region, and the drift region, wherein the gate structure comprises a gate and a gate insulating layer for isolating the gate from the source region, the well region, and the drift region;
a source metal, which is located above the source region; and
a drain metal, which is located below the substrate,
wherein, the source metal is connected to the Schottky metal via a source compacted block metal above the source metal, and at least the gate in the gate structure is isolated from the source metal, the Schottky metal, and the source compacted block metal,
the well region is provided to be in contact with the main trench, and the side, close to the main trench, of the well region is not completely covered by the source region;
the gate structure comprises a polycrystalline silicon trench gate structure;
a gate trench separated from the main trench is provided downwardly in the surface of the well region at an area which is at the side, close to the main trench, of the well region and is not completely covered by the source region, wherein the gate trench has a depth greater than a depth of the well region, and a wall, at a side distant from the main trench, of the gate trench is in contact with the source region, the well region, and the drift region at the same time; and
the gate insulating layer of the trench gate structure is provided on a bottom and walls of the gate trench, and is used to isolate the gate of the trench gate structure provided in the gate trench from the source region, the well region, and the drift region.