Effect of carrier lifetime enhancement on the performance of ultra-high voltage 4H-SiC PiN diodes

A long minority carrier lifetime is desirable to improve the on-state performance of ultra-high voltage 4H-SiC bipolar devices. This paper presents a study of lifetime enhancement processes applied to lightly doped, free-standing 4H-SiC substrates. An optimized carbon implantation and annealing process is developed, which resulted in a lifetime of 9.7 μs (increased from 2.1 μs in as-received wafers). PiN diodes were fabricated on these wafers, which show improved on-state performance as compared to diodes fabricated on as-received wafers.