US 12,218,240 B2
Source/drain regions of FinFET devices and methods of forming same
Kun-Mu Li, Zhudong Township (TW); Heng-Wen Ting, Pingtung (TW); Yen-Ru Lee, Hsinchu (TW); and Hsueh-Chang Sung, Zhubei (TW)
Assigned to TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed on Jul. 3, 2023, as Appl. No. 18/346,511.
Application 17/460,453 is a division of application No. 16/441,337, filed on Jun. 14, 2019, granted, now 11,107,923, issued on Aug. 31, 2021.
Application 18/346,511 is a continuation of application No. 17/460,453, filed on Aug. 30, 2021, granted, now 11,735,664.
Prior Publication US 2023/0352589 A1, Nov. 2, 2023
Int. Cl. H01L 29/78 (2006.01); H01L 21/02 (2006.01); H01L 29/08 (2006.01); H01L 29/66 (2006.01)
CPC H01L 29/785 (2013.01) [H01L 21/02129 (2013.01); H01L 21/02532 (2013.01); H01L 29/0847 (2013.01); H01L 29/66545 (2013.01); H01L 29/6681 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A device comprising:
a first fin and a second fin extending from a substrate;
an isolation region over the substrate, the isolation region being between the first fin and the second fin;
a gate stack over the first fin and the isolation region;
a first source/drain region in the first fin adjacent the gate stack and in the substrate, wherein a bottom surface of the first source/drain region is below a bottom surface of the isolation region, the first source/drain region comprising:
a first source/drain material comprising silicon germanium having a first concentration of germanium and a first concentration of boron;
a second source/drain material over the first source/drain material, the second source/drain material comprising silicon germanium having a second concentration of germanium and a second concentration of boron, wherein the second concentration of germanium is greater than the first concentration of germanium, wherein the second concentration of boron is greater than the first concentration of boron; and
a third source/drain material over the second source/drain material, the third source/drain material comprising silicon germanium having a third concentration of germanium and a third concentration of boron.