Normally-Off SiC VJFETs for 800 V and 1200 V Power Switching Applications

This paper reports on the development of a normally- off 4H-SiC VJFET power switch technology suitable for drop in replacement in switching-mode power supplies (SMPS). The fabricated devices exhibited a low specific on-resistance (Ron-sp) measured at V
_DS
=1 V and V
_Gs
=2-5 V. The transistors designed for 800 V applications had R
_ON-SP
< 2.9 mOmegaldrcm
²
and R
_ON-SP
< 6.6 mOmegaldrcm
²
at 25degC and 200degC, respectively. The devices designed for 1200 V application had R
_ON-SP
< 4.3 mOmegaldrcm
²
at 25degC and R
_ON-SP
< 12.8 mOmegaldrcm
²
at 200degC. The total delay time of 73 ns was measured on a 1200 V device when switching from 600 V to 4.9 A with the gate bias ranging from 0 V to 2.75 V. The highest measured off-state drain voltage blocked by a 1200 V device at V
_GS
=0 V exceeded 1800 V with the total drain leakage of 1 mA.