Monolithically Integrated High-Power GaN Devices and Si CMOS Circuits for High Frequency and High Power Converter

University Of California-San Diego, La Jolla CA

Investigators

Abstract

Approaches to integrate high efficiency and high frequency switches with control electronics can substantially reduce losses in power conversion and accelerate the development of compact, light-weight high performance power modules for electric vehicles, motor drive, photovoltaics, power factor correctors, and uninterruptible power supplies. The Gallium Nitride (GaN) material has recently demonstrated exceptional performance as a high-power switch on the individual device level but the overall power converter performance, size, and cost are compromised when these individual devices are assembled to printed circuit boards that contain the control circuitry and magnetics. Novel integration approaches that combine innovations at all levels of material, device, and packaging of power electronic devices are necessary. Building on a recent development in our laboratory for the successful growth of thick (that is suitable for high-power) GaN layers on Si, this project aims to monolithically integrate the Si gate driver circuits alongside the high power GaN devices and demonstrate co-functionality in a compact high power system. The physics and materials science of this system along with the research results will be integrated into the curriculum of compound semiconductor devices, power and energy classes at UC San Diego. The research will also be conducted with a variety of educational, mentoring, and outreach activities that will involve and recruit underrepresented and minority students. If successful, the integrated devices proposed in this project will substantially increase energy savings and reduce its costs. This project will develop the epitaxy techniques for the growth of thick crack-free GaN material on Si, the fabrication of vertical GaN switches, and their co-integration with Si drive electronics to demonstrate a monolithic high performance power converter. The epitaxy technique will result in thick GaN layers that are of high quality with low dislocation densities and low background doping in order to sustain high breakdown voltages, and the approach will utilize a few high temperature processes in order to co-integrate Si drive circuits near the GaN devices (power diodes and switches). Power converters will be assembled by implementing the developed monolithic high-power integrated circuit and its performance at high frequency with high output power and efficiency will be evaluated. The developed processes will have the potential to significantly advance the fundamental electronic materials research in power devices and their efficient system level integration.