COMPARING REACTIVE ION ETCHING OF III-V COMPOUNDS IN CL-2 BCL3/AR ANDCCL2F2/BCL3/AR DISCHARGES/

The reactive ion etching (RIE) of GaAs, AlGaAs, InP, InGaAs, InGaAsP i n Cl-2/BCl3/Ar or CCl2F2/BCl3/Ar discharges is investigated as a funct ion of the plasma parameters: power, pressure, and relative compositio n as well as etching time. For the reason of In-based fluoride with hi gh boiling point, the etching rates of all of these materials are fast er in Cl-2/BCl3/Ar in comparison to CCl2F2/BCl3/Ar. The In-based compo unds show a similar dependence on power density and discharge composit ion, but it is quite different from GaAs. When discharges containing C Cl2F2 are used, the surface morphologies are quite rough after the tre atment of RIE with either type of discharge, although smooth etching s urfaces can be obtained under appropriate conditions. Using BCl3 conta ining gas discharges will enhance smooth surface and maintain high etc hing rate. For selective etching of GaAs on AlGaAs, gas mixtures conta ining CCl2F2 are used. High performance and high selective etching can be obtained by using CCl2F2/BCl3/Ar gases mixtures. Photoresist or Si O2 were used as etching masks. Silicon dioxide is better than the phot oresist mask for its low etching rate and sputtering to III-V compound s, and it could be in situ removed by CF4 plasma. The photoluminescenc e measurements show high performance of etched results when the power density was maintained at less than 0.6 W/cm(2).