Analysis of 1.2 kV JBS rectifiers fabricated in 4H-SiC

Abstract

In this work we investigate the current–voltage characteristics of fabricated junction barrier Schottky (JBS) rectifiers with different aluminium implantation profiles in their p-type grid regions. Good performance characteristics of 1.2 kV JBS, Schottky and implanted PiN diodes processed on the same 4H-SiC wafer have been tested. A bilayer Ni/Ti anode contact metallization scheme submitted to high-temperature rapid thermal anneals is proved to form both good ohmic contact on p+ implanted areas and good Schottky characteristics on lightly doped n-type regions. High-temperature current–voltage characteristics have been evaluated up to 560 K. At room temperature, Schottky diodes have slightly better specific on-resistance, but when the operating temperature is increased, the JBS diode exhibits better characteristics due to the temperature-dependent activation of bipolar current injection from the p+ grid. From reverse measurements, the JBS diodes showed lower leakage current and higher breakdown voltages in comparison to those of the Schottky diodes in the whole range of temperatures. Moreover, we have proved the influence of the doping profile in JBS p-type grid regions on their forward on-resistance.