US 12,471,307 B2
Semiconductor device and method for manufacturing semiconductor device
Tomoyuki Funabasama, Yokkaichi Mie (JP); and Toshitaka Miyata, Yokkaichi Mie (JP)
Assigned to KIOXIA CORPORATION, Tokyo (JP)
Filed by Kioxia Corporation, Tokyo (JP)
Filed on Aug. 30, 2022, as Appl. No. 17/898,893.
Claims priority of application No. 2022-047895 (JP), filed on Mar. 24, 2022.
Prior Publication US 2023/0307540 A1, Sep. 28, 2023
Int. Cl. H10D 30/60 (2025.01); H01L 21/265 (2006.01); H01L 21/266 (2006.01); H10D 64/01 (2025.01)
CPC H10D 30/601 (2025.01) [H01L 21/26506 (2013.01); H01L 21/266 (2013.01); H10D 64/021 (2025.01)] 9 Claims
OG exemplary drawing
 
1. A semiconductor device comprising a transistor, the transistor comprising:
a gate insulating film formed on a semiconductor substrate;
a gate electrode formed on the gate insulating film and containing germanium at least in an upper region of the electrode;
a source region formed in the semiconductor substrate; and
a drain region formed in the semiconductor substrate;
wherein the transistor comprises a first side wall provided such that it faces one side surface of the gate electrode, and a second side wall provided such that it faces the opposite side surface of the gate electrode, and wherein the upper region of the gate electrode includes an intermediate portion provided between the first side wall and the second side wall and containing germanium at a first concentration, a first upper end portion located nearer to the first side wall than the intermediate portion and containing germanium at a second concentration, and a second upper end portion located nearer to the second side wall than the intermediate portion and containing germanium at a concentration lower than the first concentration and the second concentration, or containing no germanium.