Evaluation of the High Performance 650 v Cascode GaN FET under Low Temperature

Low temperature power electronics is beneficial in many different applications. Wide band gap (WBG) devices are becoming increasingly popular due to their high performances over the traditional silicon (Si) technology. Different from the gallium nitride (GaN) enhancement mode (E-mode) device, the cascode GaN is composed of a low voltage Si MOSFET and a depletion mode GaN. The advantages of the cascode GaN over E-mode GaN are: 1) easy of drive; 2) high noise immunity. In this article, the cryogenic evaluation results, including both static and dynamic characterizations, for a state-of-the-art high performance 650 V GaN cascode field-effect transistor (FET) are presented and analyzed. The evaluated 650 V cascode GaN FET has better performance under cryogenic temperatures, like low on-state resistance, large threshold volatge, reduced switching times and switching losses. Comparison results with the 650 V E-mode GaN device are made, the results demonstrate that the cascode GaN would be more reliable due to the high threshold voltage.