Low interface trap density for remote plasma deposited SiO2 on n-type GaN

Metal-oxide-semiconductor capacitors were prepared with remote plasma-enhanced chemical vapor deposition of SiO2 at similar to 300 degrees C on an n-type GaN epitaxial layer grown by atmospheric pressure metalorganic chemical-vapor deposition on a sapphire substrate. No hysteresis was observed in the high-frequency capacitance-voltage (C-V) measurements, and the measured C-V curve agreed with the C-V behavior calculated for an ideal oxide with the same flat-band voltage as the measured C-V curve. The absence of hysteresis and stretchout in the measured C-V curve and the increase of capacitance with incident ultraviolet light while in deep depletion suggest a low concentration of interface traps. These results demonstrate previous predictions of the absence of Fermi-level stabilization at the interface for the ionic crystal GaN. (C) 1996 American Institute of Physics.