Ma. Parker et al., ACCURATE ELECTRON-CYCLOTRON-RESONANCE ETCHING OF SEMICONDUCTOR-LASER HETEROSTRUCTURES USING A SIMPLE LASER REFLECTOMETER, IEEE photonics technology letters, 8(6), 1996, pp. 818-820
An in situ method of monitoring the electron cyclotron resonance etchi
ng of III-V semiconductor heterostructures is discussed for in-plane l
asers, Surface reflected and Fabry-Perot interference signals determin
e the etch depth, rate and surface quality. The etching accuracy is be
tter than 500 Angstrom. The etch monitor eliminates the dependence of
accurate etching on calibrated etch rates, as well as the need for sel
ective gas etchants and etch-stop layers typically required for comple
x heterostructure devices. The presented in situ method can be integra
ted into a digital data acquisition system, for accurate, reproducible
process control in an automated manufacturing environment.