Fabrication and Characterization of 4H-SiC pn Diode with Field Limiting Ring

4H-SiC pn diodes with field limiting rings(FLRs) were fabricated and characterized. The dependences of reverse breakdown voltage on the number of FLRs, the distance between p-base main junction and first FLR, and activation temperatures, were investigated. Al and B ions were implanted and activated at high temperature to form p-base and p+ region in the n-epilayer, respectively. We have obtained up to 1790V of reverse breakdown voltage in the pn diode with two FLRs on 10mum thick epilayer. The differential on-resistances of the fabricated diode are 5.3 MOmegacm(2) at 100A/cm(2) and 2.7mOmegacm(2) at 1kA/cm(2), respectively. All pn diodes with FLRs have higher avalanche breakdown voltages than those without an FLR. This study reveals that the FLR edge termination techniques for SiC pn diodes can provide high blocking voltage as well as low on-resistance.