DRY ETCHING AND IMPLANT ISOLATION CHARACTERISTICS OF ALXGA1-XAS GROWN BY METAL ORGANIC MOLECULAR-BEAM EPITAXY

We report on the dry etching rates of highly doped, n- and p-type AlxGa1-xAs in PCl3/Ar, CCl2F2/Ar and CH4/H2/Ar electron cyclotron resonance plasmas. These etching rates are independent of doping level and conductivity type for all three gas mixtures, and a significant dependence of etch rate on AlAs mole fraction is observed only with CCl2F2/Ar. The formation of high resistivity layers by oxygen or hydrogen ion bombardment was also investigated as a function of implant dose, Al composition and post-implant annealing temperature. Approximately 10 electrons or holes were removed from the conduction process for each 120 keV O+ ion, whereas a 40 keV proton removed about 0.3 carriers per ion. Sheet resistances above 10(8) OMEGA-square-1 are obtainable for heavily doped n- or p-type AlGaAs provided the oxygen or proton doses are sufficiently high.