Band offset of Al1− x Si x O y mixed oxide on GaN evaluated by hard X-ray photoelectron spectroscopy

An Al1-xSixOy mixed oxide has been deposited on GaN by plasma-enhanced atomic layer deposition. The band diagrams between the mixed oxide and GaN for various Si atom fraction x values are determined by hard X-ray photoelectron spectroscopy for the first time. The band gap of the mixed oxide increases with increasing x. This dependence has a large bowing parameter of 1.5 eV. We have successfully obtained conduction band offset (Delta E-C) and valence band offset (Delta E-V) as a function of x: Delta E-C (eV) = 1.6 + 0.4x + 1.2x(2) and Delta E-V (eV) = 1.7 + 0.34x + 0.36x(2). These relationships enable us to design GaN metal-oxide-semiconductor devices using the Al1-xSixOy mixed oxide. (C) 2017 The Japan Society of Applied Physics