US 12,261,053 B2
Substrate processing with selective etching
Ivo Otto, IV, Albany, NY (US); and Subhadeep Kal, Albany, NY (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by TOKYO ELECTRON LIMITED, Tokyo (JP)
Filed on Aug. 10, 2022, as Appl. No. 17/885,228.
Prior Publication US 2024/0055268 A1, Feb. 15, 2024
Int. Cl. H01L 21/311 (2006.01); H01J 37/32 (2006.01); H01L 21/02 (2006.01)
CPC H01L 21/31116 (2013.01) [H01J 37/32449 (2013.01); H01L 21/0217 (2013.01); H01L 21/02532 (2013.01); H01J 2237/3341 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of etching comprising:
providing a substrate having a base, a first layer above the base and a second layer above the base, wherein the first layer comprises Ge, and the second layer comprises Si, the second layer either including no Ge or Ge in an amount less than the first layer, and wherein the first and second layers are vertically stacked such that one of the first and second layers is vertically above the other of the first and second layers;
treating a side surface of the first layer with nitrogen radicals to form a nitrided surface on the side surface of the first layer; and
etching a side surface of the second layer while the side surface of the first layer is protected with the nitrided surface to indent the side surface of the second layer with respect to the side surface of the first layer and thereby provide an indentation in the second layer.