Barrier inhomogeneity and leakage current transport mechanism in vertical Pt/Gd2O3/GaN Schottky diodes

Vertical Pt Schottky contacts to bulk GaN single crystal with an ultrathin Gd2O3 interlayer grown by atomic layer deposition were electrically characterized using temperature dependent current-voltage (I-V-T) and capacitance-voltage (C-V) measurements. The forward I-V characteristics of the Schottky diodes revealed a temperature dependence of barrier height, and were explained by thermionic emission involving barrier inhomogeneity. Based on the thermally activated process, the dominant transport mechanism for reverse leakage current was determined to be Poole-Frenkel emission with the trap energy of 0.78 eV. The flat-band barrier height estimated from C-V method was 1.33 eV. The analysis on C-V data showed very low interface state density, indicating that Gd2O3 is a promising passivation layer in vertical GaN devices.

Automated summary

Vertical Pt Schottky contacts to bulk GaN single crystal with an ultrathin Gd2O3 interlayer grown by atomic layer deposition were electrically characterized using temperature dependent current-voltage (I-V-T) and capacitance-voltage (C-V) measurements. The results showed temperature dependence of barrier height and dominant transport mechanism for reverse leakage current as Poole-Frenkel emission with a trap energy of 0.78 eV. Evaluation from C-V data indicated Gd2O3 as a promising passivation layer due to low interface state density.