This article presents the feasibility of extending the well-known Si LOCOS (localized oxidation of Si) technology to SiC. Two isolation processes have been structurally evaluated to find an optimal, isoplanar isolation technology for SiC device integration. The first is an extension of the conventional LOCOS process which exploits the differential oxidation ratio between SiC and Si3N4. The second technique, called the " field-poly" process, uses a selective oxidation of polysilicon over SiC to form the isolating field region. Scanning electron micrographs show the typical bird’s beak around the active area border with a width of 0.92 mum per side for the LOCOS process (field oxide = 3000 angstrom) and 0.55 mum per side for the field-poly process (field oxide = 8000 angstrom). Compared to the mesa isolation currently used for SiC, the new technologies improve structural planarity while allowing self-aligned field threshold implants for isolation between adjacent devices.