XPS STUDY ON DRY-ETCHING OF SI GEXSI1-X

Reactive ion etching characteristics of epitaxial Ge0.25Si0.75 in SF6/ O2/He plasma has been investigated by X-ray photoelectron spectroscopy . Compositional information like Ge/Si and O/F ratios in the reaction layers on both horizontal and sidewall areas have been determined. The etch rate enhancement of the Si component is believed to be due to a disproportionation-type reaction path involving fluorine transfer from Ge to Si, which is suppressed, in the presence of oxygen and at low s ubstrate temperature, leading to the important role of ion bombardment in the etch mechanism.