Optical and electronic effects of rapid thermal annealing at Ir–Ga2O3 interfaces

Abstract

Ir is a common impurity in the edge-defined film-fed growth method used to produce high-power Ga2O3 device structures and growth substrates; yet, the effects of this deep level defect on carrier transport and recombination, particularly at high device processing and operating temperatures and at metal interfaces, have yet to be explored. The optical and electronic nature of Ir in Ga2O3 and at Ir/ Ga2O3 interfaces change on a near-nanometer to micrometer scale after nitrogen rapid thermal annealing; the understanding and control of which could lower defect-assisted tunneling, improve diode rectification, and preserve critical electric field strength. Depth-resolved cathodoluminescence spectroscopy, interface electronic current, and capacitance–voltage measurements reveal how this dominant impurity in bulk, edge-fed crystal growth diffuses, evolves with temperature, and impacts defect formation and Schottky barrier formation.