Structural and electrical characterizations of the pulsed-laser-deposition- grown Sc2O3/GaN heterostructure

Abstract

Single-crystalline Sc2 O3 was grown on GaN/sapphire template using pulsed laser deposition and the interface characteristics of the Sc2 O3 GaN heterostructure were investigated. An epitaxial relationship of [112] Sc2 O3 ∥ [21 3- 0]GaN and (222) Sc2 O3 ∥ (0002)GaN was revealed by x-ray diffraction and cross-sectional transmission electron microscopy. A valence band offset of 0.84 eV was obtained by x-ray photoelectron spectroscopy, indicating a conduction band offset of 2.04 eV across the Sc2 O3 GaN heterointerface. In addition, a low interface state density of 4× 1011 eV-1 cm-2 was estimated from capacitance-voltage measurements. The epitaxial nature with good interface characteristics has rendered a substantially low leakage current of 1 μA cm2 at a reverse gate bias of 30 V in the Sc2 O3 GaN metal-oxide-semiconductor structures. © 2006 American Institute of Physics.