(Electronics and Photonics Division Award) Research Advances Wide- and Ultrawide-Bandgap Power Switching Devices

Abstract

Wide bandgap semiconductors such as SiC and GaN (WBG) and emerging ultrawide-bandgap materials such as Ga2O3, AlGaN, and Diamond (UWBG) represent the next-generation materials for high performance medium voltage and high voltage power switch technology. Such devices have a wide range of immediate Naval applications, including high-power satellite communications and radar, unmanned underwater and aerial vehicles, ship drive components, and hybrid vehicle inverters. Vertical SiC power device technology has matured rapidly over the past two decades, owing to advances in substrates, a fundamental understanding of epitaxial growth to eliminate performance-limiting defects, as well as device design breakthroughs. This has enabled breakthroughs in highly integrated module design for medium voltage power conversion with switching frequency >100 kHz. In parallel, lateral GaN-based high electron mobility transistor (HEMT) technology has been highly successful for RF power amplifiers and is well positioned to supersede GaAs-based microwave circuits. Recently, GaN-based vertical and lateral power devices have attracted significant interest due to promising device results coupled with progress in native substrate, epitaxial growth, and processing technology developments. This seminar will present an overview of the WBG/UWBG power device efforts at NRL. This research has four primary focus areas – 1) thermal management in III-N power device structures by diamond thin film integration, 2) characterization of substrate materials and homoepitaxial layers used for drift regions of power devices identify appropriate specifications and benchmark performance, 3) process module development, particularly for selective area doping by ion implantation, and 4) pilot production manufacturing of 1.2kV-class PiN diodes including reliability assessments to identify and mitigate performance limiting defects.