High voltage 4H SiC rectifiers using Pt and Ni metallization

We have fabricated high voltage 4H SiC rectifier diodes using Ni and Pt as metals for the Schottky contacts. At a current density of 100 A/cm(2), these diodes had a forward voltage drop of 1.76 and 1.86 V, respectively, Both Ni- and Pt-SiC diodes had breakdown voltages > 1000 V. Pt-based SiC diodes exhibited a higher on-off current ratio ( > 10(8)) and lower ideality factor ( 1.11) at room temperature than the Ni-based diodes (> 10(6) and 1.29). The diodes were operated at elevated temperatures up to 450 degrees C for forward bias and 300 degrees C for reverse bias. The room temperature barrier height of Ni on 4H SiC was determined to be 1.31 eV and the specific on-resistance of the diodes was found to be similar to 8 m Omega-cm(2).