US 12,444,614 B2
Etch selectivity modulation by fluorocarbon treatment
Ivo Otto, IV, Albany, NY (US); Toshiki Kanaki, Albany, NY (US); Jonathan Hollin, Nirasaki (JP); and Subhadeep Kal, Albany, NY (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Aug. 22, 2023, as Appl. No. 18/453,843.
Prior Publication US 2025/0069896 A1, Feb. 27, 2025
Int. Cl. H01L 21/311 (2006.01); H10D 30/01 (2025.01); H10D 30/67 (2025.01); H10D 62/10 (2025.01); H10D 64/01 (2025.01); H10D 84/01 (2025.01); H10D 84/03 (2025.01); H10D 84/85 (2025.01)
CPC H01L 21/31116 (2013.01) [H10D 30/014 (2025.01); H10D 30/6735 (2025.01); H10D 62/121 (2025.01); H10D 64/017 (2025.01); H10D 84/0167 (2025.01); H10D 84/038 (2025.01); H10D 30/6757 (2025.01); H10D 84/85 (2025.01)] 20 Claims
OG exemplary drawing
 
1. A method of fabricating a field effect transistor (FET) over a substrate, the method comprising:
growing a doped p-type semiconductor from a silicon nanosheet of the substrate, the substrate comprising a layer stack of alternating layers of the silicon nanosheet and a sacrificial layer, and a dummy gate formed over the layer stack, the layer stack comprising a trench exposing sidewalls of the layer stack, the doped p-type semiconductor and the sacrificial layer being separated by a dielectric inner spacer;
removing the dummy gate; and
etching the sacrificial layer selectively to the doped p-type semiconductor, the etching comprising exposing the substrate to a process gas comprising a fluorocarbon and a fluorine-containing etch gas in the absence of plasma.