1,530V, 17.5 mΩcm2 normally-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 15 mum n-type drift layer doped to n=5.7x10(15) cm(-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 mOmegacm(2) at J(D)=100A/cm(2) and V-G=3.5V. The VJFET conducts a drain current of 1.13A (227A/cm(2)) 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.