Study on Schottky Al x Ga1- x N/GaN IMPATT Diodes for Millimeter-Wave Application

This article proposes a Schottky aluminum gallium nitride (AlGaN)/GaN single-drift-region (SDR) IMPATT diode that uses AlGaN as the avalanche active layer. Compared with GaN, AlGaN has a wider bandgap and better breakdown characteristics. These features can significantly improve the device performance. We simulated the direct current (DC) and radio frequency (RF) performances of the new structure for the 0.2–0.6 Al composition under the millimeter-wave band and compared the results with the conventional GaN avalanche layer IMPATT. The results indicate that the AlGaN avalanche layer IMPATT significantly improves the breakdown voltage, RF voltage, and RF current performances. Furthermore, the application of AlGaN avalanche layer increases the RF efficiency from 18.16% to 21.98% and increases the RF power from 1.56 to 2.67 MW/cm2. As this structure has greater potential for the millimeter wave, even terahertz application, this article brings a new reference for the design of GaN-based IMPATT diodes.