Study of electrical characteristics of high quality Pt SBDs fabricated on HVPE-Grown β-Ga2O3 epilayers in a wide temperature range (80–525 K)

Abstract

In this study, we have experimentally investigated the temperature endurance capability of high-quality Pt-based Schottky Barrier Diodes (SBDs) fabricated on halide vapor phase epitaxy (HVPE)-grown β-Ga2O3 and carried out a detailed analysis of the conduction mechanism. The measurements have been performed over a wide temperature range of 80–525 K, and the prepared SBDs showed outstanding thermal stability over repeated cycles of electrical measurements. A high Schottky barrier height (SBH) greater than 1 eV with near unity ideality factor was obtained at 300 K for the prepared SBDs. The temperature dependence of SBH indicated the barrier inhomogeneity at Pt/Ga2O3 interface, which was modelled using the Werner-Güttler barrier inhomogeneity model. The ideality factor initially decreased with the increase of temperature from 80 K to 300 K, and at higher temperatures, a near unity ideality factor was observed, which can be attributed to the dominance of pure thermionic emission current transport mechanism at higher temperatures. A very high rectification ratio (RR) of the order of 107 was observed for the prepared Pt/Ga2O3 SBD, which was persistent over the entire temperature range. SBH (φ)C–V calculated from the capacitance-voltage characteristics were found to decrease with increasing temperature, and their temperature coefficient values of −3.74 to −7.29 × 10−4 eV/K were observed, which can be attributed to the narrowing of the bandgap of Ga2O3 with the increase of temperature. A negligible value of intrinsic carrier concentration below 300 K and a low value of the order of 10−5 – 10−6 cm−3 at room temperature was observed, which indicated the excellent quality of HVPE-grown Si-doped (001) β-Ga2O3 epilayers. The obtained results confirm the excellent thermal stability and endurance of fabricated Pt/Ga2O3 SBDs, which can find application in advanced power electronic devices.