IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

259 / 2017-11-23 00:11:14

A Near Ideal Edge Termination Technique for Ultrahigh-Voltage 4H-SiC Devices with Multi-Zone Gradient Field Limiting Ring

Plenary track > Device structures and fabrication techniques

In this paper, an improved 4H-silicon carbide (SiC) junction barrier Schottky (JBS) rectifier with the application of multi-zone gradient filed limiting ring (MZG-FLR) is proposed and fabricated without extra process steps or masks. Multi-zone variable ring spacings for the FLR termination are applied to improve the blocking voltage by reducing the peak surface electric field at the edge termination region, which acts like a variable lateral doping profile resulting in a gradual field distribution. A breakdown voltage of 14 kV at a leakage current of 1×10–5A is achieved from the fabricated rectifiers with a 100 μm thick N– epi-layer doped to 5×1014 cm–3, which is nealy 99% of the ideal parallel-plane value. A forward current density of 20 A/cm2 has been measured at a forward voltage drop of 4.1 V for devices with an active area of 0.15 mm2. The simulation and experimental results show that the proposed device exhibits approximately 50% improvement in the reverse blocking voltage, and indicate that MZG-FLR structure is promising as an ultrahigh voltage operation device (>10kV) for high-power electronic systems applications.