Novel CH4/H2 metalorganic reactive ion etching of Hg1−xCdxTe

We have for the first time shown that CH4/H2 metalorganic reactive ion etching (MORIE) of Hg1−xCdxTe is feasible for mesa-etching to dimensions less than 2 μm. Process parametric effects on etch rate, surface anisotropy, and surface stoichiometry were studied with particular emphasis on the methane to hydrogen MORIE process ratio as well as Hg1−xCdxTe alloy composition. A laser interferometric detection scheme was employed for in situ measurement of etch rates as well as for end-point detection. A self-induced etch-stop mechanism for certain etch-gas compositions is also demonstrated.