US 12,363,945 B2
Method of forming source/drain regions with quadrilateral layers
Tsz-Mei Kwok, Hsinchu (TW); Yung-Chun Yang, New Taipei (TW); Cheng-Yen Wen, Taichung (TW); Li-Li Su, Chubei (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 Apr. 4, 2022, as Appl. No. 17/657,822.
Claims priority of provisional application 63/224,485, filed on Jul. 22, 2021.
Prior Publication US 2023/0028591 A1, Jan. 26, 2023
Int. Cl. H10D 30/67 (2025.01); H01L 21/02 (2006.01); H01L 21/285 (2006.01); H10D 30/01 (2025.01); H10D 62/10 (2025.01); H10D 62/40 (2025.01); H10D 64/01 (2025.01)
CPC H10D 30/6713 (2025.01) [H01L 21/02521 (2013.01); H01L 21/0259 (2013.01); H01L 21/02609 (2013.01); H01L 21/28518 (2013.01); H10D 30/031 (2025.01); H10D 30/6735 (2025.01); H10D 30/6757 (2025.01); H10D 62/118 (2025.01); H10D 62/405 (2025.01); H10D 64/017 (2025.01); H10D 64/018 (2025.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
forming a protruding semiconductor stack comprising:
a plurality of sacrificial layers; and
a plurality of nanostructures, wherein the plurality of sacrificial layers and the plurality of nanostructures are laid out alternatingly;
forming a dummy gate structure on the protruding semiconductor stack;
etching the protruding semiconductor stack to form a source/drain recess; and
forming a first source/drain region comprising:
growing first epitaxial layers in the source/drain recess, wherein the first epitaxial layers are grown on sidewalls of the plurality of nanostructures, wherein a cross-section of each of the first epitaxial layers has a quadrilateral shape, and wherein the first epitaxial layers have a first dopant concentration; and
forming a second epitaxial layer on the first epitaxial layers, wherein the second epitaxial layer has a second dopant concentration higher than the first dopant concentration.