High‐voltage 4H‐SiC pn diodes fabricated by p‐type ion implantation

We formed a low‐resistance p region by high‐dose aluminum (Al) ion implantation in the 4H‐SiC (0001) face, and fabricated and characterized planar pn diodes by Al or boron (B) ion implantation. In Al ion implantation, the minimum sheet resistance of 3.6 kω/□ (p‐type) is obtained by high‐temperature implantation and high‐temperature annealing. Excellent rectification was verified in planar pn diodes, in which the surface p + layer was formed by high‐temperature implantation of Al ions and the p layer was formed by room‐temperature implantation of high‐energy B ions. We achieved a high blocking voltage of 2900 V (90% of the theoretical withstand voltage), a low on‐resistance of 8.0 mωcm 2 , and avalanche breakdown characteristics of a positive temperature coefficient for the blocking voltage. We fabricated a 4H‐SiC (11 2 0) pn diode, which has not been disclosed previously, and obtained a high blocking voltage of 1850 V (70% of the theoretical blocking voltage).