US 12,300,717 B2
Semiconductor device and method of manufacture
Yu-Chang Lin, Hsinchu (TW); Chun-Hung Wu, New Taipei (TW); Liang-Yin Chen, Hsinchu (TW); Huicheng Chang, Tainan (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 Feb. 14, 2022, as Appl. No. 17/670,740.
Claims priority of provisional application 63/230,108, filed on Aug. 6, 2021.
Prior Publication US 2023/0042196 A1, Feb. 9, 2023
Int. Cl. H01L 29/06 (2006.01); H01L 21/8234 (2006.01); H01L 29/786 (2006.01)
CPC H01L 29/0665 (2013.01) [H01L 21/823412 (2013.01); H01L 21/823418 (2013.01); H01L 21/823468 (2013.01); H01L 29/78618 (2013.01); H01L 29/78696 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
depositing a multi-layer stack over a semiconductor substrate, the multi-layer stack comprising a plurality of sacrificial layers that alternate with a plurality of channel layers;
forming a first recess in the multi-layer stack;
forming first spacers on sidewalls of the sacrificial layers in the first recess;
depositing a first semiconductor material in the first recess, wherein the first semiconductor material is undoped, wherein the first semiconductor material is in physical contact with a sidewall and a bottom surface of at least one of the first spacers;
implanting dopants in the first semiconductor material, wherein after implanting dopants the first semiconductor material has a gradient-doped profile;
forming an epitaxial source/drain region in the first recess over the first semiconductor material, wherein a material of the epitaxial source/drain region is different from the first semiconductor material;
removing the sacrificial layers to form a second recess; and
forming a gate structure in the second recess.