Breakthroughs for 650-V GaN Power Devices: Stable high-temperature operations and avalanche capability

Abstract

Many prior publications have focused on gallium nitride (GaN) dynamic Rdson issues at room temperature, even though GaN power devices have tremendous advantages over silicon (Si) when serving at high temperatures. We show that room-temperature stable dynamic Rdson behavior does not guarantee device reliability, and it is the stable high-temperature dynamic Rdson that determines the ruggedness of the GaN power devices. With our proprietary and innovative designs and optimizations of epitaxial and device structures, we show a completely different dynamic Rdson behavior in contrast to the common trend reported in the literature: a negative dynamic Rdson trend. We demonstrate robust performance and reliability of our new cascode GaN power devices in PFC tests conducted at both room and high temperatures, at high powers, at high-frequency conditions, and in a totem-pole circuit. We speculate on a physical model to explain the observed dynamic Rdson behaviors in terms of trapping, detrapping, and back-gating effects.