Effect of Temperature on the Electrical and Current Transport Properties of Au/Nd₂O₃/n-GaN Metal/Interlayer/Semiconductor (MIS) Junction

Abstract

The Au/Nd₂O₃/n-type GaN metal/interlayer/semiconductor (MIS) junctions were fabricated with high-k rare-earth oxide interlayer and explored its electrical properties in the wide temperature range of 150–400 K. An anomalous decrease in barrier height and an increase in the ideality factor with a decrease in the temperature were observed. The anomalous barrier height and ideality factor are ascribed to a role of barrier inhomogeneities at the interface of MIS junction assuming a double Gaussian distribution of barrier heights in the temperature ranges of 150–225 K and 225–400 K. Double Gaussian distribution giving mean barrier heights of 0.84 eV and 1.23 eV and standard deviations of 0.0085 V and 0.0187 V for the two temperature regions. A modified conventional energy plot gives mean barrier height $\left( {\overline{\Phi }_{bo} } \right)$ and Richardson constant (A*) as 0. eV and 13.44 Acm⁻² K⁻² (150–225 K) and 1.23 eV and 22.85 Acm⁻² K⁻² (250–400 K), respectively. The estimated A* value in the temperature range of 250–400 K was closely matched with the theoretical value of n-type GaN. Moreover, results express that the obtained interface state density of the MIS junction decreases with increasing temperature. Results explained that the reverse current conduction governed by Poole–Frenkel emission at the temperature range of 150–225 K and Schottky emission at 250–400 K, respectively.