Silicon vs silicon carbide device characterization

Significant development of silicon carbide (SiC) material for device applications now allows circuit designers to more fully exploit its unique properties. The 4 H-SiC structure provides the most favorable characteristics to optimize device speed and power handling capabilities. These include wide bandgap (3.2 eV), high dielectric breakdown (3.5 MV/cm), and high thermal conductivity (4.9 W/cm-K) [IEEE Transactions on Electron Devices, 1993]. By combining these properties, SiC devices are able to achieve fast reverse recovery and high reverse blocking voltages, along with excellent high temperature characteristics (case temperatures above 150 C). This makes these devices ideally suited to power electronics applications, where high power levels as well as fast switching are required. Many areas dominated by ultrafast recovery silicon (Si) diodes, might therefore be better suited to the application of SiC. In order to verify the efficacy of SiC devices, temperature dependent measurements were made on a sample of fast recovery Si and SiC diodes. This paper presents the results of these measurements, comparing critical characteristics of Si and SiC devices over a range of junction temperatures up to 150 C.