Process Compatibility of Heavily Nitrogen Doped Layers Formed by Ion Implantation in Silicon Carbide Devices

Abstract

Heavily doped layers were formed in 4H-SiC device epitaxial structures comprised of moderately doped n layer (channel) and heavily doped p+ layer (gate). The n+ regions were formed by local ion implantation of nitrogen followed by post-implantation annealing with graphite capping layer. It was shown that annealing at 1700 °C is required for complete activation of implanted impurities. The post-implantation anneals were found to have no significant effect on the moderately nitrogen doped channel layer. On the other hand it resulted in noticeable deterioration of electrical propertied of heavily doped epitaxial p+ layers leading to the increase of contact resistivity which has to be taken into account in design and processing of SiC devices.