Thermally induced voltage shift in capacitance–voltage characteristics and its relation to oxide/semiconductor interface states in Ni/Al2O3/InAlN/GaN heterostructures

Abstract

The Ni/Al2O3/InAlN/AlN/GaN metal-oxide-semiconductor heterostructure (MOS-H) is investigated using capacitance–voltage and capacitance–time characteristics in the temperature range of 25–300 °C. An anomalous positive voltage shift of the capacitance–voltage curve with increasing temperature was observed and attributed to the hole emission from the oxide/semiconductor interface states. Distribution of the interface states density, Dit(E), at the Al2O3/InAlN interface was evaluated using a modification of the constant-capacitance deep-level transient spectroscopy. The MOS-H capacitor threshold voltage shift under negative bias was repetitively recorded as a function of time at elevated temperatures. Dit in the range of 0.1–3 × 1013 eV−1 cm−2 was determined.