SiC and GaN Wide Bandgap Device Technology Overview

Abstract

Wide bandgap (WBG) devices offer significant advantages for next generation military and commercial systems. SiC MESFETs currently achieve power densities of 4.0 W/mm with power added efficiencies in excess of 60% on a repeatable basis. They are commercially available in packaged or die formats and have been successfully designed into a number of systems. GaN is also extremely promising as a next generation wide bandgap device. Cree has demonstrated power densities higher than 25 watts per mm of gate periphery. With f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">tau</sub> 's > 40 GHz, GaN devices have the capability of satisfying system device requirements from UHF through millimeter-wave. Both technologies are now also offered through commercial MMIC foundry services using design rules and non-linear models provided for external designers. Significant progress has also been made in the development of 100-mm SiC substrates and WBG epitaxy (SiC and GaN) which is key for commercializing the technology and providing low costs. Micropipe densities as low as 2.5 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> have been demonstrated for 100-mm HPSI substrates and both SiC and GaN epitaxy with excellent intra-wafer sheet resistance uniformity have been demonstrated. With robust reliability for SiC MESFETs now established for several years, the latest results for GaN device reliability benchmarking are shown.