A study on laser direct dry etching of GaAs/AlGaAs multi-layer

초록

It has been studied the direct dry etching of GaAs/AlGaAs multi-layer using Ar+ laser. Local temperature profile on the surface with a laser irradiation was calculated by three dimensional heat transfer equations to analyze etching characteristics. The temperature rise of GaAs was higher than that of AlGaAs at close by their melting points. It is expected that laser-induced thermal reaction is more active for GaAs than for AlGaAs at same etching condition. The reaction gas of CCl2F2 flowed through a vacuum chamber at a pressure of the range 160 to 760 Torr. Etched width of the GaAs/AlGaAs interface was larger than that of the AlGaAs/GaAs interface. This result is because that an etch rate of GaAs is larger than that of AlGaAs. The maximum etch rate of the multi-layer was 32.5 um/sec and the maximum etched width ratio of GaAs to AlGaAs was 1.7. We will discuss that this special etch profiles obtained in this study can be applied for a waveguide of optoelectronics and a cantilever of MEMS.