Thermal and Electrical Performance of CMOS Driver Compatible GaN Power Transistors

This paper describes the thermal and electrical characteristics of GaN on SiC power transistors that have been designed to be mounted directly upon a CMOS driver integrated circuit. In order to maximize the customer value proposition and minimize the cost implications of using a high capability GaN on SiC die, the hybrid device has to exhibit substantial performance and convenience advantages over a simple cascode structure based upon discrete transistors. The design was also directly influenced by the very complex and costly discrete component PCB based driver designs needed by SiC and IGBT power devices. The size, cost and inconvenience of these driver designs arises from the very high discrete component count, which may reach triple digits for the half bridge configuration. This paper describes the design of the GaN transistor and a compatible CMOS driver. This new self powered integrated structure reduces the external component count to single digit totals. In this paper, methods are discussed for modeling and validating each step of the product development.