Accurate electron-cyclotron-resonance etching of semiconductor laser heterostructures using a simple laser reflectometer

An in situ method of monitoring the electron cyclotron resonance etching of III-V semiconductor heterostructures is discussed for in-plane lasers. Surface reflected and Fabry-Perot interference signals determine the etch depth, rate and surface quality. The etching accuracy is better than 500 /spl Aring/. The etch monitor eliminates the dependence of accurate etching on calibrated etch rates, as well as the need for selective gas etchants and etch-stop layers typically required for complex heterostructure devices. The presented in situ method can be integrated into a digital data acquisition system, for accurate, reproducible process control in an automated manufacturing environment.