Thick Epitaxial Layers on 4º Off-Oriented 4H-SiC Suited for PiN-Diodes with Blocking Voltages above 6.5 kV

Abstract

This work presents results on the growth of thick epitaxial layers on 4° off-oriented 4HSiC in a commercially available hot-wall CVD system. Results on background doping level, homogeneity of thickness and doping, and run-to-run reproducibility will be shown. Defect structures we observed on 4° off-oriented substrates only are discussed. AFM measurements are presented to show the degree of step-bunching. 6.5 kV PiN-diodes with an active device area of 5.7 mm2 were fabricated and electrically characterized. In spite of the surface defects and stepbunching, up to 50% of the devices per wafer fulfilled our strict yield criteria even at 6.5 kV. Up to the onset of avalanche, the devices exhibited extremely low leakage currents. These results turn the cheaper 4° off-oriented substrates into a promising choice for producing higher volumes of highvoltage SiC power devices at reasonable costs.