Design and evaluation of low-voltage power AlGaN/GaN/SiC Schottky barrier diode

The paper presents the results of the development and experimental evaluation of a low-voltage planar power Schottky diode based on an AlGaN/GaN heterostructure formed on a SiC substrate. The basic design of a GaN power Schottky diode with a field-effect electrode system implemented in a multi-finger GaN power Schottky diode crystal was described. A technique for pulsed measurement of the diode's current-voltage characteristic was presented, which allows eliminating the influence of self-heating. Twenty-five experimental samples of GaN power Schottky diode dies were fabricated and measured. The maximum working voltage was over 250 V, and the maximum current reached 42 A. The thermal resistance between the active region of the GaN power diode and the substrate was theoretically calculated. The advantage of using SiC substrates in terms of thermal characteristics was demonstrated. A comparison of the achieved electrical characteristics of the GaN power Schottky diode with a commercially-available silicon-based counterpart was conducted. The paper presents the results of integrating an experimental sample of a power GaN Schottky diode die into a multichip power micromodule intended for use in the secondary stage of high-power-density single-ended DC-DC converters.