Reactive ion etching of SiGe alloys using HBr

We have studied reactive ion etching of Si1-xGex alloys with x≤0.15 and Ge in HBr plasmas. The etch rate of SiGe increases monotonically with the Ge content of the alloy and for a Si85Ge 15 alloy was ≅50% greater than for Si. Etch profiles are identical to those formed in singe-crystal Si. X-ray photoelectron spectroscopy studies shown that the surface of the etched SiGe alloys are depleted in Ge and consist of about one monolayer of brominated Si over the alloy.