Temperature dependent electron cyclotron resonance etching of InP, GaP, and GaAs

Electron cyclotron resonance etching of InP, GaP, and GaAs in Ar, Ar/Cl 2, Ar/Cl2/H2, and Ar/Cl2/H2/CH4 plasmas is reported for substrate temperatures from 10 to 170 °C. Etch rates increased as a function of temperature for GaP and GaAs in an Ar/Cl2 plasma. With the addition of H2 or H2/CH4 to the plasma, the GaP and GaAs etch rates decreased and were essentially temperature independent. In comparison, InP etch rates showed a strong temperature dependence regardless of plasma chemistry. At 170 °C, InP etch rates were greater than GaP and GaAs in the Ar/Cl2/H2 and Ar/Cl2/H 2/CH4 plasmas. Atomic force microscopy was used to determine the root‐mean‐square roughness of the etched surfaces. The etched surface morphology for InP was strongly dependent on temperature and plasma chemistry while smooth pattern transfer was obtained for a wide range of plasma conditions for GaAs and GaP.