Electron cyclotron resonance etching of GaAs vias for monolithic microwave integrated circuits

Abstract We report a high etch rate GaAs via hole etching using Cl 2 /Ar plasma in an electron cyclotron resonance system. The effects of process parameters, such as RF power, gas flow rate, and microwave power on the GaAs etch rate were investigated. The influence of RF power, process pressure, and etch time on the resultant profiles were studied. The GaAs etch rate was found to increase significantly as Cl 2 flow rate, and RF power or microwave power increased. A maximum etch rate of 6 μm/min has been obtained. Studies also showed that sidewall profile for via patterns can be controlled by varying process pressure and RF power.