Study of p-(6H, 4H, 3C)SiC/n-GaN Heterojunction SDR, DDR IMPATT Diodes

In this article, three polytypes of p-(6H, 4H, 3C)SiC and n-GaN heterojunction single-drift (SDR) and double-drift (DDR) impact-ionization-avalanche-transit-time (IMPATT) diodes are studied. We conduct the numerical simulations of the direct current (DC), radio frequency (RF), and noise characteristics of IMPATT diodes. The results show that (6H)SiC/GaN IMPATT diodes have the optimum RF characteristics. Among them, the RF power density of (6H)SiC/GaN DDR IMPATT diode can reach 2.23 MW/cm2. The DC-RF conversion efficiency of (6H)SiC/GaN SDR IMPATT diode can reach 23.4%. Their noise performances are being examined in the meantime. The (3C)SiC/GaN IMPATT has better noise characteristics in the SDR structure, while (4H)SiC/GaN IMPATT has better noise characteristics in the DDR structure. This study provides a reference for the design and fabrication of IMPATT diodes.