N-type doping of 4H-SiC with phosphorus co-implanted with C or Si

Phosphorus has been shown to be a much better dopant than nitrogen in 4H-SiC for heavily doped n-type implantation. In this paper, the effect of co-implantation of phosphorus with carbon or silicon is studied. The implanted layers are characterized by an analytical technique (secondary ion mass spectrometry). Electrical measurements include sheet resistance and Hall measurements as well as forward and reverse I-V characterization of the resulting n+/p rectifiers. The effect of co-implantation of P/C and P/Si on the electrical activation of phosphorus has been monitored. After 1700 degreesC anneal, respective sheet resistance values of 111 and 132 ohm/square were measured. Forward characteristics of these diodes are observed to obey a generalized Sah-Noyce-Shockley multiple level recombination model with four shallow levels and one deep level.