High Power (500V-70A) and High Gain(44-47) 4H-SiC Bipolar Junction Transistors

Abstract

This paper reports high power 4H-SiC BJTs with record high current handling capabilities. Wet-oxygen low-temperature re-oxidation and aluminum-free Ohmic contacts were applied in the fabrication processing. Up to 7A(Jc=583A/cm 2 ) with a single BJT cell has been achieved at V CE =5.5V. The peak DC common emitter current gain reached 47 at Ic=4.7A (Jc=392A/cm 2 ) and Vce=6.5V. The open base blocking voltage (Vceo) reached up to 858V with 1mA leakage current. The specific on-resistance was measured to be 8.7m Ω·cm 2 up to Ic=5.5A (Jc=458A/cm 2 ) at Vce=4.0V. At 150 o C, the peak current gain was still as high as 36 at Ic=3.6A at Vce=10V. The specific on-resistance at 150 o C was 13.2m Ω·cm 2 up to Ic=4.0A (Jc=333A/cm 2 ) at Vce=4.4V. At 100 o C, the open base blocking voltage was measured up to 875V with 1mA leakage current. A 4H-SiC BJT package containing nine similar BJT cells was also fabricated and tested. The highest collector current was measured up to 70A. The peak DC current gain was 44.3 at Ic=44.3A(Jc=410A/cm 2 ) and Vce=5.5V. The open base blocking voltage for the package at 500V showed a leakage current of 8mA. Its inductively-loaded half-bridge switching results are also reported.