Photoelectrochemical conductivity selective etch stops for SiC

Recent advances in SiC technology have demonstrated that the material is a potentially useful semiconductor for high temperature and high frequency applications. However, unlike silicon and GaAs, SiC is chemically inert, thus limiting the amount of etchants that can be effectively used to pattern devices. In fact, no patterning technique has been reported to date for SiC which shows high selectivity between p- and n-type material. In this letter, we will show how an n-type SiC epilayer can be patterned using photoelectrochemical etching, while a p-type substrate underneath acts as an etch stop. This process is useful for the fabrication of electromechanical transducers, mesa structures, and bipolar and CMOS devices in SiC.