SiC bipolar transistors for RF applications

The wide bandgap (WBG) semiconductor SiC has been identified as a potential candidate for use in high power and high frequency devices due to its superior material parameters. SiC has a breakdown field almost six times higher than that of Si or GaAs resulting in a higher attainable power density. SiC has a larger thermal conductivity, 3 times that of Si and 6 times that of GaAs, translating into a smaller chip size and, therefore, more efficient systems. To date, most research on SiC RF devices has focused on majority carrier devices such as SITs and MESFETs. There are only a few reports on SiC bipolar transistors and these studies have concentrated on SiC power switching transistors. Bipolar transistors have potentially superior linearity as well as higher current handling and power density capabilities compared to the aforementioned RF devices making BJTs ideal for use in power amplifiers.