Abstract
In the literature Si-Ge channel n-type MOSFET has been proven being able to enhance 10-20% electron channel mobility. Based on the fact that Ge implantation in Si or SiC substrate was feasible, in this study we propose to use Ge ion implantation to promote electron channel mobility in SiC MOSFETs without post oxidation annealing. The implanted doses of phosphorus and aluminum for the source, drain, and body were above 1016 cm-2. From the experimental results, the n-type and p-type contact resistivities were improved. For the Ge ion implantation, effects from different implantation doses and electrical activation temperatures were investigated. From the results, SiC MOSFETs with low dose Ge implantation showed a maximum drain current density of 5.76x10-2A/mm, a low on-resistance of 11.42mΩ•cm2, and a channel mobility of 22.74cm2/V-s. It is attributed to the high electron mobility of Ge. The most important of all, compared with high dose Ge implantation, surface roughness scattering is reduced to a minimal level, and the electron channel mobility can be improved to a level comparable with those observed with post oxidation annealing in nitrogen-based gas.