Experimental study and characterization of an ultrahigh-voltage Ni/4H–SiC junction barrier Schottky rectifier with near ideal performances

Abstract

An ultra-high voltage SiC JBS (silicon carbide junction barrier Schottky) rectifier utilizing a novel area-efficient multi-zone gradient modulated field limiting ring (MGM-FLR) technique have been fabricated, measured, and analysed in this paper. Ni-Schottky metal with a high barrier height is used to achieve a better trade-off between the on-resistance and the breakdown voltage. MGM-FLR, which is implanted simultaneously with the P+ grids within the active area of the device, forms a similar variation of lateral doping to mitigate the electric field crowding caused by junction curvature effect and obtains a maximum blocking voltage with minimally sized edge termination area. The fabricated device is tested to obtain a specific on-resistance is 140 mΩ cm2 and a reverse breakdown voltage of 14 kV with the leakage current of 10 μA, which is quite close to the theoretical value of parallel plane junction calculated using the device parameter of drift region 100 μm and the concentration 5 × 1014 cm−3. The highest Baliga's figure-of-merit (BFOM) 5.6 GW/cm2 was obtained for the proposed devices. Furthermore, the distribution of the extracted barrier height versus ideality factor on the wafer are demonstrated using I–V method. Impacts of ring spacing and zone of MGM-FLR termination on SiC device reverse blocking performance are also investigated in detail.