Surface Phenomena During Plasma-Assisted Atomic Layer Etching of SiO.

Surface phenomena during atomic layer etching (ALE) of SiO were studied during sequential half-cycles of plasma-assisted fluorocarbon (CF) film deposition and Ar plasma activation of the CF film using in situ surface infrared spectroscopy and ellipsometry. Infrared spectra of the surface after the CF deposition half-cycle from a CF/Ar plasma show that an atomically thin mixing layer is formed between the deposited CF layer and the underlying SiO film. Etching during the Ar plasma cycle is activated by Ar bombardment of the CF layer, which results in the simultaneous removal of surface CF and the underlying SiO film.