Papers by Author: Anders Lindgren

Abstract: Vertical epitaxial NPN SiC BJTs for 1200 V rating were fabricated. Very low collector-emitter saturation voltages VCESAT=0.5 V at IC=6 A (JC=140 A/cm2) and T=25 °C and VCESAT=1.0 V at IC=6 A and T=250 °C were measured. The common emitter current gain at IC=6 A is 71 at T=25 °C and 32 at T=250 °C, respectively. A SPICE model was developed for the BJT including the parasitic capacitances of the internal pn junctions, as well as temperature dependence of the current gain and the collector series resistance. The IC-VCE characteristics of the BJT are in good agreement with the SPICE model between 25 °C and 250 °C. Fast switching measurements were performed showing a VCE voltage fall-time of 22 ns and a VCE voltage rise-time of 11 ns.

Abstract: This paper reports large active area (15 mm2) 4H-SiC BJTs with a low VCESAT=0.6 V at IC=20 A (JC=133 A/cm2) and an open-base breakdown voltage BVCEO=2.3 kV at T=25 °C. The corresponding room temperature specific on-resistance RSP-ON=4.5 mΩcm2 is to the authors knowledge the lowest reported value for a large area SiC BJT blocking more than 2 kV. The on-state and blocking characteristics were analyzed by device simulation and found to be in good agreement with measurements. Fast switching with VCE rise- and fall-times in the range of 20-30 ns was demonstrated for a 6 A 1200 V rated SiC BJT. It was concluded that high dynamic base currents are essential for fast switching to charge the BJT parasitic base-collector capacitance. In addition, 10 μs short-circuit capability with VCE=800 V was shown for the 1200 V BJT.