1,530V, 17.5 mωcm²normally-off 4H-SiC VJFET design, fabrication and characterization

This paper reports the design, fabrication and characterization of a double-gated, normally-off 4H-SiC VJFETs with implanted vertical channel, which eliminates the need of epitaxial re-growth in the middle of the device fabrication. A normally-off VJFET, which is based on a 15μm n-type drift layer doped to n=5.7×10¹⁵cm^-3, is demonstrated with a blocking voltage (V_B) of 1,530V with a leakage current of 15mA. The specific on-resistance (R_{SP_ON}) is found to be 17.5 mωcm ² at J_D=100A/cm² and V_G=3.5V. The VJFET conducts a drain current of 1.13A (227A/cm²) at V _G=3.5V and V_D=5V with a corresponding gate current of 16mA, resulting in an I_D/I_G ratio of 70. VJFETs with different lateral JFET channel opening dimensions have been designed and fabricated. Detailed design, fabrication and characterization results of the VJFETs are reported, including the DC I-V relations, the effects of LJFET channel opening dimensions, the specific on-resistance, and the temperature-dependent performance.