Growth and characterization of thick multi-layer 4H-SiC epiwafer for very high-voltage p-channel IGBTs

Thick multi-layer 4H-SiC epitaxial growth was investigated for very high-voltage Si-face p-channel insulated gate bipolar transistors (p-IGBTs). The multi-layer included n buffer, p field stop, and thick p drift layers. Two processes were employed to enhance the carrier lifetime of the p drift layer: carbon ion implantation/annealing and hydrogen annealing, and the enhanced carrier lifetime was confirmed by the open-circuit voltage decay measurement. Using the grown thick multi-layer 4H-SiC, simple PiN diodes were fabricated instead of p-IGBTs to demonstrate efficient conductivity modulation in the thick p drift layer. While the on-state voltage was high at room temperature, it decreased significantly at elevated temperatures, and attained 3.5 V at 100 A/cm at 200°C for the diode with the carrier lifetime enhancement processes, indicating sufficient conductivity modulation.