A method for manufacturing a semiconductor device includes: forming a semiconductor structure on a semiconductor substrate, the semiconductor structure including first and second source/drain regions disposed on the semiconductor substrate in a first direction and spaced apart from each other in a second direction transverse to the first direction, and a plurality of channel features disposed between and connected to the first and second source/drain regions and spaced apart from one another in the first direction; forming an interfacial material layer to cover the channel features; forming a metal oxide layer on the interfacial material layer; converting a portion of the interfacial material layer into a metal silicate layer so as to form a plurality of interfacial features respectively covering the channel features, the metal silicate layer being formed between the metal oxide layer and the interfacial features; and removing the metal oxide layer and the metal silicate layer.

Methods and associated devices including the fabrication of a semiconductor structure that provides a silicon-on-insulator substrate. The semiconductor structure may be formed by providing a base substrate, forming a sacrificial layer over the base structure, and forming a semiconductor layer over the sacrificial layer. The sacrificial layer is removed to form a void that is filled with oxide. The semiconductor structure includes a dielectric support feature extending through the semiconductor and oxide layers and/or a portion of the oxide layer extends to the surface of the semiconductor layer.

A substrate processing method includes preparing a substrate having a target film including silicon, carbon, and nitrogen on a surface of the substrate; supplying hydrogen gas and oxygen gas to the target film to oxidize a surface layer of the target film and form an oxide film; and etching the oxide film.