Avalanche phenomena in 4H-SiC p-n diodes fabricated by aluminum or boron implantation

Characteristics of p-n junction fabricated by aluminum-ion (Al/sup +/) or boron-ion (B/sup +/) implantation and high-dose Al/sup +/-implantation into 4H-SiC (0001) have been investigated. By the combination of high-dose (4/spl times/10/sup 15/ cm/sup -2/) Al/sup +/ implantation at 500/spl deg/C and subsequent annealing at 1700/spl deg/C, a minimum sheet resistance of 3.6 k/spl Omega///spl square/ (p-type) has been obtained. Three types of diodes with planar structure were fabricated by employing Al+ or B+ implantation. B/sup +/-implanted diodes have shown higher breakdown voltages than Al/sup +/-implanted diodes. A SiC p-n diode fabricated by deep B+ implantation has exhibited a high breakdown voltage of 2900 V with a low on-resistance of 8.0 m/spl Omega/cm/sup 2/ at room temperature. The diodes fabricated in this study showed positive temperature coefficients of breakdown voltage, meaning avalanche breakdown. The avalanche breakdown is discussed with observation of luminescence.