Selective reactive ion etching of GaAs/AlAs in BCl3/SF6 for gate recess

A selective reactive ion etch process for GaAs high electron mobility trans istor gate recess has been developed using BCl3/SF6 gas mixtures. The influ ence of gas flow ratio, pressure, and radio-frequency (rf) power on the sel ectivity was examined. An optimum selective etching process using a Plasma Therm 790 reactive ion etching system was determined to be 50 W rf power, g as flow ratio of BCl3/SF6 = 2.5 sccm/7.5 sccm, and chamber pressure of 50 m Torr. Excellent etch uniformity was achieved by using an HCl/ethanol soluti on to remove native oxide prior to plasma etching. (C) 2000 American Vacuum Society. [S0734-211X(00)00205-5].