Achieving high performance Ga2O3 diodes by adjusting chemical composition of tin oxide Schottky electrode

Abstract

High performance Ga2O3 Schottky barrier diodes (SBDs) are achieved by adjusting chemical composition of SnOx Schottky electrode. The SnOx is produced by radio frequency sputtering under various oxygen partial pressures (PO). A synergic study on Raman, x-ray photoelectron, and optical transmission spectroscopy of the SnOx films illustrates that: the films with PO = 0 ∼ 3.1% consist mainly SnO and Sn with high conductivity; the films with PO = 4.6 ∼ 5.4% are composed of both p-type SnO and n-type SnO2 with high resistance; the films with PO = 10.0 ∼ 13.1% are mainly dominated by n-type SnO2 with low resistivity. In addition, as PO increased from 0 to 3.1%, the SBDs performances are significantly improved due to that the SnO-dominated films reduce effectively the oxygen-deficiency at the Ga2O3 interfaces and the related interface state density. With PO = 5.4%, the high resistive SnOx results in degraded diode performance because that the SnO2 component with oxygen vacancy defects may aggravate the oxygen-deficiency at the Schottky interface. With the optimized PO of 3.1%, the SBD shows high performance with a large barrier height of 1.12 eV, a near unity ideality factor of 1.22, and a high rectification ratio of >1010.