Studies of Interface States in Sc2O3 ∕ GaN , MgO ∕ GaN , and MgScO ∕ GaN structures

Abstract

Interface trap densities have been measured in , MgO/n-GaN, and MgSc/n-GaN metal-insulator-semiconductor structures by both conductance and deep level transient spectroscopy (DLTS) methods. Both methods indicate that for energies deeper than from the conduction band-edge, the interface trap density is low, on the order of . DLTS measurements show that the interface trap density has a peak near from the bottom of the conduction band. The interface trap density measured both by conductance and DLTS methods increases in the order , MgO, MgScO, which most likely reflects the improved lattice match of corresponding oxides with GaN. For MgSc/n-GaN structures we also observed generation of additional interface traps by the application of high positive bias. The effect could be reversed after a high negative bias was applied.