Study of GaN Schottky barrier IMPATT diodes with a self-aligned field plate for terahertz applications

Abstract

This article investigates a self-aligned field plate to enhance the GaN Schottky barrier IMPATT diodes at the low-frequency end of the terahertz regime by restraining the electric field at the Anode edge to reach uniform avalanche inside the Anode. Simulation results demonstrate an improved device tolerance, a conversion power of 2.8 times larger and a conversion efficiency of 4.4 times higher than those of the none field plate, respectively, and a 1.31 times conversion efficiency of the ordinary field plate at the optimum frequency of 120 GHz, achieving 64 % of ideal conversion power and 86 % of ideal efficiency. Meanwhile, the initiating-oscillation efficiency of the self-aligned field plate is improved by 7.5 and 0.6 times at 120 GHz compared to that of the none and ordinary field plates, respectively, with speed exceeding 8.7 and 2.1 times that of the none and ordinary field plates to initiate oscillation. Furthermore, the self-aligned field plate provides the working bandwidth in 68–223 GHz, approaching that of the ideal.