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

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 <mml:mfenced close=")" open="(">Phi <mml:mo><overbar></mml:mover>bo</mml:mfenced> 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.