Dopant Incomplete Ionization Role in SiC Schottky Diode Edge Termination under Current Over-Stress

Current Crowding phenomenon is one of the most important issues compromising power device reliability. In this work a 4-H SiC Schottky diode with a junction termination extension is studied when this phenomenon occurs. TCAD modelling of the device is detailed and different doping profiles for the n-type buffer layer of the drift zone are simulated. The obtained results are assessed with experimental measurements using the Internal Infrared Laser Deflection and Free-Carrier Absorption techniques. It is highlighted that the incomplete ionization modulates the carrier concentration in the device drift layer and, consequently, it may have a certain role in this process.