4H-SiC Power BJTs with High Current Gain and Low On-Resistance


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4H-SiC BJTs have been fabricated with varying geometrical designs. The maximum value of the current gain was about 30 at IC=85 mA, VCE=14 V and room temperature (RT) for a 20 μm emitter width structure. A collector-emitter voltage drop VCE of 2 V at a forward collector current 55 mA (JC = 128 A/cm2) was obtained and a specific on-resistance of 15.4 m2·cm2 was extracted at RT. Optimum emitter finger widths and base-contact implant distances were derived from measurement. The temperature dependent DC I-V characteristics of the BJTs have been studied resulting in 45 % reduction of the gain and 75 % increase of the on-resistance at 225 oC compared to RT. Forward-bias stress on SiC BJTs was investigated and about 20 % reduction of the initial current gain was found after 27.5 hours. Resistive switching measurements with packaged SiC BJTs were performed showing a resistive fast turn-on with a VCE fall-time of 90 ns. The results indicate that significantly faster switching can be obtained by actively controlling the base current.



Materials Science Forum (Volumes 556-557)

Edited by:

N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall






H. S. Lee et al., "4H-SiC Power BJTs with High Current Gain and Low On-Resistance", Materials Science Forum, Vols. 556-557, pp. 767-770, 2007

Online since:

September 2007




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