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

High performance Ga₂O₃ Schottky barrier diodes (SBDs) are achieved by adjusting chemical composition of SnO_x Schottky electrode. The SnO_x 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 SnOdominated films reduce effectively the oxygen-deficiency at the Ga₂O₃ interfaces and the related interface state density. With PO = 5.4%, the high resistive SnO_x 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.