Reactive sputtering of gallium nitride thin films for GaAs MIS structures

Abstract
Amorphous gallium nitride was deposited onto various substrates by reactive sputtering of gallium in nitrogen ambient. Higher pressure up to 2×10−1 Torr is effective in making films closer to the stoichiometric composition. Annealing at 350 °C improves the insulating property of as‐deposited films by decreasing dc and ac conductance. The surface‐state density and time constant of a GaAs MIS structure, corrected for the dispersive behavior of the insulator, was derived as 7.6×1011 cm−2 eV−1 and 1.9×10−4 sec, respectively. This surface‐state density is much lower than that for the native oxide.