US 12,453,147 B2
Semiconductor structure and method of fabricating the semiconductor structure
Guan-Lin Chen, Hsinchu (TW); Kuo-Cheng Chiang, Hsinchu County (TW); Chih-Hao Wang, Hsinchu County (TW); Shi Ning Ju, Hsinchu (TW); and Jui-Chien Huang, Hsinchu (TW)
Assigned to TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD., Hsinchu (TW)
Filed by TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD., Hsinchu (TW)
Filed on Feb. 23, 2024, as Appl. No. 18/585,098.
Application 18/585,098 is a division of application No. 17/571,941, filed on Jan. 10, 2022, granted, now 11,942,513.
Application 17/571,941 is a continuation of application No. 16/785,296, filed on Feb. 7, 2020, granted, now 11,222,948, issued on Jan. 11, 2022.
Claims priority of provisional application 62/907,213, filed on Sep. 27, 2019.
Prior Publication US 2024/0194735 A1, Jun. 13, 2024
Int. Cl. H10D 62/10 (2025.01); H01L 21/02 (2006.01); H01L 21/265 (2006.01); H01L 21/306 (2006.01); H01L 21/3105 (2006.01); H01L 21/762 (2006.01); H10D 30/01 (2025.01); H10D 30/62 (2025.01); H10D 30/67 (2025.01); H10D 62/17 (2025.01); H10D 64/01 (2025.01)
CPC H10D 62/121 (2025.01) [H01L 21/02532 (2013.01); H01L 21/30604 (2013.01); H10D 30/024 (2025.01); H10D 30/62 (2025.01); H10D 30/6735 (2025.01); H10D 62/292 (2025.01); H10D 64/015 (2025.01); H10D 64/021 (2025.01); H01L 21/02271 (2013.01); H01L 21/26513 (2013.01); H01L 21/31053 (2013.01); H01L 21/76224 (2013.01); H10D 64/017 (2025.01)] 20 Claims
OG exemplary drawing
 
1. A method for fabricating a semiconductor structure, comprising:
forming a first silicon layer over a substrate;
forming a first silicon germanium layer over the first silicon layer, wherein the first silicon germanium layer has a first germanium concentration;
forming a second silicon germanium layer over the first silicon germanium layer, wherein the second silicon germanium layer has a second germanium concentration greater than the first germanium concentration;
forming a third silicon germanium layer over the second silicon germanium layer, wherein the third silicon germanium layer has a third germanium concentration less than the second germanium concentration;
forming a second silicon layer over the third silicon germanium layer; and
partially removing the first silicon layer, the first silicon germanium layer, the second silicon germanium layer and the third silicon germanium layer from a lateral side by an etching operation and thereby forming a recess laterally encroaching the first silicon layer, wherein a contour of the recess has a first section proximal to the lateral side, a second section connecting to the first silicon germanium layer, and a third section between the first section and the second section, and wherein an absolute value of a derivative at the third section is greater than both an absolute value of a derivative at the first section and an absolute value of a derivative at the second section.