Blocking Characteristics of 2.2 kV and 3.3 kV-Class 4H-SiC MOSFETs with Improved Doping Control for Edge Termination

Blocking characteristics of 2.2 kV and 3.3 kV -class 4H-SiC MOSFETs with various doping conditions for the edge termination region have been investigated. By optimizing the implanted dose into the edge termination structure consisting of junction termination extension (JTE) and field-limiting ring (FLR), a breakdown voltage of 3,850 V for 3.3 kV -class MOSFET has been attained. This result approximately corresponds to 95% of the parallel-plane breakdown voltage estimated from the doping concentration and the thickness of the epitaxial layer. Implanted doping for the JFET region is effective in reducing JFET resistance, resulting in the specific on-resistance of 14.2 m Omega cm(2) for 3.3 kV SiC MOSFETs. Switching characteristics at the high drain voltage of 2.0 kV are also discussed.