Roadmap for SiC power devices

Abstract

Silicon carbide (SiC) power devices offer significant benefits of improved efficiency, dynamic performance and reliability of electronic and electric systems. The challenges and prospects of SiC power device development are reviewed considering different device types. A close correlation between an exponential increase of current handling capability during recent five years and improvement in substrate quality is demonstrated. The voltage range of silicon and SiC unipolar and bipolar power devices with respect to the on-state voltage is determined based on device simulation. 4H-SiC unipolar devices are potentially superior to all silicon devices up to 10 kV. 4H-SiC unipolar devices are superior to all SiC bipolar devices up to 8-9 kV. The low end of SiC unipolar devices is determined to be around 200 V provided substrate resistance is reduced by thinning the substrate down to 100 um. The influence of reduced channel mobility on the specific on-state resistance of 4H-SiC DMOSFETs and UMOSFETs is shown. It has been demonstrated that 6H-SiC DMOSFETs could be a better choice compared to 4H-SiC MOSFETs in the voltage range below 600 V utilising better channel mobility obtainable so far on 6H-SiC polytype. An impact of super junction (SJ) concept on silicon and SiC MOSFET specific on-resistance limits is demonstrated