Fabrication and Application of 1.7KV SiC-Schottky Diodes

Abstract

High voltage 4H-SiC Ti Schottky junction barrier schottky (JBS) diode with breakdown voltage of 1700 V and forward current of 5 A has been fabricated. A low reverse leakage current below 3.8×10-5A/cm2at the bias voltage of -1700 V has been obtained. The forward on-state current was 5 A at VF= 1.7 V and 15.8 A at VF= 3 V. The active area is 1.5 mm × 1.5 mm. The turn-on voltage is about 0.9 V. The on-state resistance is 3.08 mΩ·cm2. The doping and thickness of the N-type drift layer and the device structure have been performed by numerical simulations. The SiC JBS devices have been fabricated and the processes were in detail. The die was assembled in a TO-220 package. The thickness of the N- epilayer is 17 µm, and the doping concentration is 3.2 × 1015cm−3. The number of floating guard p-rings was chosen to be 25, the distance between the rings was chosen to be 0.7 µm ~ 1.3 µm and the width of the p-rings is 2.5 µm. We use the PECVD SixNy/SiO2as the passivation dielectric and a non photosensitive polyamide as the passivation in the end. The reverse recovery current Irwas 1.26A and the reverse recovery time Trrwas 26ns when the diode was switched from 5A forward current to a reverse voltage of 700V. The reverse recovery electric charge Qrrof 16nC was obtained.