Tokyo Electron Limited

Ivo Otto, Iv

Subhadeep Kal

Toshiki Kanaki

Jonathan Hollin

A method of fabricating a field effect transistor (FET) over a substrate that includes: growing a doped p-type semiconductor from a silicon nanosheet of the substrate, the substrate including 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 including 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 including exposing the substrate to a process gas including a fluorocarbon and a fluorine-containing etch gas in the absence of plasma.

Etch selectivity modulation by fluorocarbon treatment

An etch and surface modification is performed in a plasma, in which ions have been removed so that radicals of the plasma form a modified surface of a layer of substrate. A gas chemistry is reacted with the modified surface to form a reacted modified surface, and the reacted modified surface is removed.

Substrate processing with material modification and removal

Etching is selectively performed and selectively is modified using a treatment or pre-treatment with nitrogen radicals, prior to etching. Etching is performed with a gas phase chemistry etch. Different selectivities can also be provided in different processes or different regions (or different devices or different locations) of a substrate by the selective use and non-use of the treatment.

Growing community of inventors

Albany, NY, United States of America

Ivo Otto, Iv