Selective plasma etching of Ge substrates for thin freestanding GaAs-AlGaAs heterostructures

Abstract

Selective plasma etching of Ge with a CF4/O2 mixture is used to produce freestanding GaAs-AlGaAs thin films. The etch rate of Ge substrates is as high as 150 µm/h at temperatures of 75 °C under optimized conditions and with a negligible etch rate for GaAs and AlGaAs materials. This plasma etching technique, combined with a lattice-matched growth of GaAs-AlGaAs structures on Ge substrates, has a variety of potential device applications. The characteristics of this etch process and the photoluminescence of freestanding AlGaAs-GaAs structures are presented. Applied Physics Letters is copyrighted by The American Institute of Physics.