US 11,688,807 B2
Semiconductor device and methods of forming
Hung-Tai Chang, Hsinchu (TW); Han-Yu Tang, Hsinchu (TW); Ming-Hua Yu, Hsinchu (TW); and Yee-Chia Yeo, Hsinchu (TW)
Assigned to TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed on Mar. 29, 2021, as Appl. No. 17/216,052.
Claims priority of provisional application 63/106,154, filed on Oct. 27, 2020.
Prior Publication US 2022/0131006 A1, Apr. 28, 2022
Int. Cl. H01L 29/78 (2006.01); H01L 27/092 (2006.01); H01L 29/08 (2006.01); H01L 29/417 (2006.01); H01L 29/66 (2006.01); H01L 21/8238 (2006.01)
CPC H01L 29/7839 (2013.01) [H01L 21/823814 (2013.01); H01L 21/823821 (2013.01); H01L 27/0924 (2013.01); H01L 29/0847 (2013.01); H01L 29/41791 (2013.01); H01L 29/66545 (2013.01); H01L 29/66795 (2013.01); H01L 29/7851 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A device comprising:
a first fin extending from a substrate;
a first gate stack over and along sidewalls of the first fin;
a first gate spacer disposed along a sidewall of the first gate stack; and
a first source/drain region in the first fin and adjacent the first gate spacer, the first source/drain region comprising:
a first epitaxial layer on the first fin, the first epitaxial layer having a first dopant concentration of boron; and
a second epitaxial layer on the first epitaxial layer, the second epitaxial layer having a second dopant concentration of boron, the second dopant concentration being greater than the first dopant concentration, the second epitaxial layer being an outermost layer of the first source/drain region.