High Breakdown Field p-Type 3C-SiC Schottky Diodes Grown on Step-Free 4H-SiC Mesas

Step-free surface heteroepitaxy of 3C-SiC films with improved dislocation density on patterned 4H/6H-SiC substrate mesas has recently been reported. This paper details initial investigations of the performance of electrical devices implemented in stacking-fault-free 3C-SiC. Small-area p-type Schottky diodes with 50 nm Ti/150 nm Ni contacts were fabricated on NA = 1 to 5 x 10 exp 17/cu cm unintentionally boron-doped 3C-SiC mesa films. Capacitance-voltage (CV) and current-voltage (IV) properties of the devices were measured at 24 deg C, 200, and 300 C. CV measured doping profiles (verified also by secondary ion mass spectroscopy for two of the diodes) were essentially temperature independent. The IV characteristics show excellent rectification properties with low reverse leakage and relatively sharp reverse breakdown. Room temperature breakdown voltages (where current sharply increased to exceed 0.1 A/sq cm) from 96 V down to 53 V were observed, corresponding to peak electric fields near 2 MV/cm for NA near 1 x 10 exp 17/cu cm to above 3 MV/cm for NA near 5 x 10 exp 17/cu cm. These measured 3C-SiC electric fields are comparable to reported < 1120 > and < 0338 > 4H-SiC breakdown fields.