Reactive Ion Etching of ZnS Films using a Gas Mixture of Methane/Hydrogen/Argon

ZnS epitaxial layers grown using metalorganic vapor phase epitaxy were etched by reactive ion etching (RIE) employing a gas mixture of CH 4 , H 2 and Ar. The etching rates were investigated as functions of the plasma parameters: rf power density, the relative composition and the total flow rate of reactive gases. It was determined that the amount of CH 4 in CH 4 /H 2 gas discharge decides whether a polymer will be produced. The optimum composition of the mixed gas was 1CH 4 /7H 2 /4Ar, when the pressure, rf power density and total flow rate were 30 mTorr, 0.4 W/cm 2 and 30 sccm, respectively. The quality of the etched surfaces under these conditions was examined using X-ray photoelectron spectroscopy and photoluminescence. It was determined that the etching process does not damage the ZnS film based upon the results of photoluminescence spectra.