Interface properties of plasma-enhanced chemical vapor deposited SiOxNy/n-GaAs metal-insulator-semiconductor system

Interface properties of plasma-enhanced chemical vapor deposited SiO_xN_y/n-GaAs metal-insulator-semiconductor systems are investigated by capacitance-voltage and deep level transient spectroscopy measurements. At room temperature, these metal-insulator-semiconductor devices exhibit deep depletion mode operation which is characteristic of the low thermal generation rate for minority carriers in GaAs and the large number of traps located at or near the interface. For accumulation mode bias voltage, the small signal capacitance does not approach the SiO_xN_y capacitance and exhibits anomalous frequency dispersion behavior. A simple method is used to correlate the capacitance-voltage and deep level transient spectroscopy data. An interface-state band model best fits the experimental results.