A Superior Reverse Characteristics of 1.2 kV 4H-SiC Planar JBS Diode Employing Channeling Implantation

Abstract

This paper presents a study on improving the reverse characteristics of 1.2 kV 4H-SiC JBS diodes by employing a deep P+ grid structure. To achieve a deep junction with low implantation energy, channeling implantation was implemented. Diodes with different junction depths of the P+ grid were fabricated to compare the forward and reverse I-V characteristics; depth of 0.8 μm, 1.4 μm, and 2.2 μm. Almost identical forward I-V characteristics were achieved regardless of the P+ grid depth. However, the leakage current was significantly suppressed by the deeper P+ grid junction depth; 60 μA, 1.5 μA, and 1.7 nA (at 1200V for 0.8, 1.4, 2.2 μm deep P+ grids, respectively). Although the deep junction was implemented with channeling implantation, high breakdown voltages similar to that of the shallow junction are achieved in the proposed JBS diode. This is due to the relatively low doping concentration in the deep junction. Moreover, the edge termination structures with different main junction depths were discussed. For a near ideal breakdown voltage insensitive to the JTE dose, Hybrid-JTE was employed. It was demonstrated that the high breakdown voltage with the drastically reduced leakage current of the proposed JBS diodes, was achieved using identical edge termination technology to the conventional shallow junction. To better understand the effect of the deep junction, 2D simulation was conducted.