Temperature Dependent Current-Voltage Characteristics of GaN (si) Heterojunction Barrier Schottky Diodes (HJBS)

Distinct current transport mechanisms were observed in the fabricated heterojunction barrier Schottky diodes (HJBS) depending on the temperature ranging from -80°C to 80 ${}^{\circ}\mathrm{C}$ under applied bias. At forward bias, in region I $(\mathrm{V}_{\mathrm{f}} < 0.5 \ \mathrm{V})$ , at higher temperatures $(\geq-20 \ {}^{\circ}\mathrm{C})$ , multi-tunneling capture-emission model (MTCE) is as the main conduction mechanism, and at lower temperatures $(< -20{}^{\circ}\mathrm{C})$ , thermionic emission is the main conduction mechanism with the barrier height inhomogeneities at the interface. In region II $(0.5\ \mathrm{V} < \mathrm{V}_{\mathrm{f}} < 0.9 \ \mathrm{V})$ , the conduction mechanism is dominated by Fowler-Nordheim tunneling. All mechanisms above are affected by defects in $\text{GaN}$ which may formed by carbon atoms. The leakage current mechanism of degenerate devices can be summarized as follow: at lower reverse voltage $(\mathrm{V}_{\mathrm{r}} < 50\mathrm{V})$ , barrier reduction effect is dominant; In the case of higher reverse voltage $(\mathrm{V}_{\mathrm{r}} > 50 \ \mathrm{V})$ , the Space-Charge-Limited Currents (SCLC) mechanism is dominant.