Interface characterization of atomic layer deposited Al₂O₃ on m-plane GaN

The interfaces between dielectrics and semiconductors play a dominant role in the performance of both electronic and optoelectronic devices. In this article, we report the band offset characterization of atomic layer deposited Al₂O₃ on non-polar m-plane (Formula presented.) GaN grown by hybrid vapor phase epitaxy using X-ray photoelectron spectroscopy (XPS). The surface band bending of GaN was investigated by employing the angle resolved XPS (ARXPS). The Fermi level pinning is found to be at ∼2.4 eV above valence band maximum near the surface. The valence band offset and conduction band offset at the Al₂O₃ and m-plane GaN interface were determined to be 1.0 and 2.2 eV respectively. Electrical measurement was done by using metal–oxide–semiconductor capacitor. Capacitance–voltage hysteresis loop indicated low density of oxide traps. The frequency dependent C–V curves also showed a small dispersion.