Reactive ion beam etching of ZnSe and ZnS epitaxial films using Cl2 electron cyclotron resonance plasma

Publisher Website
Google Scholar
Abstract
Reactive ion beam etching of ZnSe and ZnS epitaxial films was carried out using pure Cl2 as an etching gas. Electron cyclotron resonance plasma was excited at pressures of 2.5×10−4 –2.5×10−3 Torr. Chlorine ions were extracted with voltages of 0–400 V. Sputtering yields were strongly dependent on the extraction voltage and the gas pressure. The etching mechanism starts with the generation of chloride compounds, mainly ZnClx, by the chemical reaction of the surface and chlorine radicals, mainly Cl atoms. The chloride compounds are subsequently sputtered off by the accelerated ion beam. The crystalline quality of etched ZnSe films was characterized by photoluminescence measurements. We found that high quality etched films, which have almost no damage and no Cl contamination, can be obtained at an extraction voltage of about 300 V.