Inductively Coupled Plasma Etching of III-Nitrides in Cl_2/Xe, Cl_2/Ar and Cl_2/He

摘要

The role of additive noble gases He, Ar and Xeto Cl_2-based Inductively Coupled Plasmas for etching of GaN,AlN and InN were examined. The etch rates were a strongfunction of chlorine concentration, rf chuck power and ICPsource power. The highest etch rates for InN were obtainedwith Cl_2/Xe, while the highest rates for AlN and GaN wereobtained with Cl_2/He. Efficient breaking of the III-nitrogenbond is crucial for attaining high etch rates. The InN etchingwas dominated by physical sputtering, in contrast to GaN andAlN. In the latter cases, the etch rates were limited by initialbreaking of the III-nitrogen bond. Maximum selectivities ofapprox 80 for InN to GaN and InN to AlN were obtained.