P+ implanted 6H-SiC n+-i-p diodes: evidence for a post-implantation-annealing dependent defect activation

Two n+-i-p 6H-SiC diode families with P+ ion implanted emitter have been processed with all identical steps except the post implantation annealing: 1300°C/20min without C-cap has been compared with 1950°C/10min with C-cap. The analysis of the temperature dependence of the reverse current at low voltage (-100V) in the temperature range 27-290°C shows the dominance of a periphery current which is due to generation centers with number and activation energy dependent on the post implantation annealing process. The analysis of the temperature dependence of the forward current shows two ideality factor n region, one with n = 1.9/2 at low voltage and the other one with 1 < n < 2 without passing through 1 for increasing voltages. For both the diode families the current with n = 1.9/2 is a periphery current due to recombination centers with a thermal activation energy near the 6H-SiC mid gap. In the forward current region of 1 < n < 2, the two diode families show different ideality factor values which could be attributed to a different post implantation annealing defect activation.