Anisotropy effects on the performance of wurtzite GaN impact-ionization-avalanche-transit-time diodes

摘要

We demonstrate that a GaN impact-ionization-avalanche-transit-time (IMPATT) diode exhibits a higher frequency and a wider bandwidth in the basal plane (Gamma-M direction) than along the c-axis (Gamma-A direction). Because of the better efficiency, RF power, and negative resistance performance at a high frequency, the use of the diode in the Gamma-M direction is more appropriate for high-frequency operation. In addition, the diodes are cut off when the specific contact resistances are similar to 10(-6) and similar to 10(-5) Omega.cm(2). Thus, the very high specific contact resistance of p-type GaN of about similar to 10(-4) Omega.cm(2) provides an important limitation to the fabrication of pn junction GaN IMPATT diodes. (C) 2016 The Japan Society of Applied Physics