ELECTRICAL IMPACT CHARACTERIZATION OF ANODE ACTIVE AREA AND STACKING-FAULTS IN 6.5 KV 4H-SIC PIN DIODES

Abstract

This paper reports on the design and characterization of 6.5kV class 4H-SiC PiN diodes with different active
areas of 2, 8, and 24mm2. Diodes edge termination is a combination of MESA and JTE. The blocking voltage of
6.5kV was achieved on the three types of diodes. Diodes operation stability is studied in term of temperature
dependence and DC stress. In the limit of used package, these diodes present a stable operation until 225°C. The
reverse leakage current at 225°C is less than 3µA at 3kV for 24mm2 diodes. The forward voltage drop decreases
with the increasing temperature but the voltage change is low, less than 0.5V in the temperature range of (25°C
- 225°C). After a DC stress under current density as high as 100A.cm-2, an important on-state forward voltage
drift has been observed. This voltage drift is explained by the generation and prolongation of stacking-faults
(SFs) which result in the reduction of carrier lifetime. A reduction of up to two times has been measured by opencircuit voltage decay (OCVD) technique. These diodes are also characterized by mean of admittance spectroscopy
vs. temperature. These measures revealed an electronic energy level at 0.18eV under the conduction band for the
stressed diodes thus this energy level can be attributed to an electrical signature of SFs.