Characteristics of thermal oxides grown on GaAs1 − xPx

Abstract Oxides were thermally grown on GaAs 1 − x P x of various mole fractions x using dry oxygen or steam at various temperatures. The elemental composition of the oxide films as a function of depth was examined using ion microprobe mass analysis. Our results indicated that the grown layers were arsenic deficient through the bulk of the oxide and arsenic rich near the oxide-semiconductor interface region. Capacitance-voltage ( C-V ) characteristics of metal-insulator-semiconductor (MIS) capacitor structures displayed the deep depletion behavior typically observed with wide band gap semiconductor MIS devices. The characteristics also exhibited a hysteretic nature indicative of electron trapping at the oxide-semiconductor interface. The interface trap densities estimated from analysis of the C-V characteristics were in the range (5−9) × 10 11 cm -2 eV -1 . Post-oxidation annealing of the films in argon or nitrogen generally resulted in increased dielectric leakage current and in reduced C-V hysteresis effects. The correlation of electrical and ion microprobe data demonstrates the important role of arsenic in determining the electrical properties of the MIS devices.