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4H-SiC layers have been homoepitaxially grown at a high growth rate of 25 m/h by chimney-type vertical hot-wall chemical vapor deposition at 1700°C. Through photoluminescence measurement, the intrinsic defect, so-called L 1 peak, was found to be reduced under a C-rich condition. In the deep level transient spectroscopy measurement, the Z 1 center was also found to be suppressed under a C-rich condition. For a 75-m-thick epilayer, the net donor concentration was reduced to as low as 5ϫ10 12 cm Ϫ3. In low-temperature photoluminescence, free exciton peaks are dominant, indicating high purity of the epilayer.

The p-i-n diodes were fabricated using 31-m thick n -and p-type 6H-SiC epilayers grown by horizontal cold-wall chemical vapor deposition (CVD) with nitrogen and aluminum doping, respectively. The diode exhibited a very high breakdown voltage of 4.2 kV with a low on-resistance of 4.6 mcm 2 . This on-resistance is lower (by a factor of five) than that of a Si p-i-n diode with a similar breakdown voltage. The leakage current density was substantially lower even at high temperatures. The fabricated SiC p-i-n diode showed fast switching with a turn-off time of 0.18 s at 300 K. The carrier lifetime was estimated to be 0.64 s at 300 K, and more than 5.20 s at 500 K. Various characteristics of SiC p-i-n diodes which have an advantage of lower power dissipation owing to conductivity modulation were investigated.Index Terms-Minority carrier lifetime, on-resistance, p-i-n diode, power device, SiC.

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