Reactive ion etching of ZnSe, ZnSSe, ZnCdSe and ZnMgSSe by H2/Ar and CH4/H2/Ar

The etching characteristics of ZnSe, ZnS0.07Se0.93, Zn0.88Cd0.12Se and Zn0.95Mg0.05S0.09Se0.91 have been studied using 2CH(4)/9H(2)/2Ar and 9H(2)/2Ar as the reactive ion etching (RIE) etching gas. It was demonstrated that a smooth surface and a good anisotropic feature can be achieved when these samples are etched in 9H(2)/2Ar at 60 mTorr with a 150 W plasma power. Under this etching condition, the etching rates of ZnSe, ZnS0.07Se0.93, Zn0.88Cd0.12Se and Zn0.95Mg0.05S0.09Se0.91 were 7.8 nm/min, 9.5 nm/min, 10.4 nm/min and 8.3 nm/min, respectively. Carbon-related needlelike features were observed when methane was added to the etching gas, and these needlelike features can be removed by a high plasma power. Photoluminescence (PL) measurement shows that 9H(2)/2Ar can induce a greater amount of surface damage than 2CH(4)/9W(2)/2Ar. However, these damages can be partially removed by post etching annealing. The optimal annealing temperature is 450 degrees C for samples etched in 9H(2)/2Ar and 250 degrees C for samples etched in 2CH(4)/9H(2)/2Ar.