Transistor heat generation in wide bandgap power amplifier transistors is today in excess of several kW/cm2 and can result in temperature spikes, or “hotspots,” approaching 100K in the near-junction region. Novel, high flux cooling techniques are under development to enable successful exploitation of the inherent operational capability of wide bandgap amplifiers. Micro-contact enhanced thermoelectric coolers, using an integral pillar etched directly in the electronic substrate to concentrate cooling on the sub-mm transistor hotspot, is a most promising near-junction thermal management technique. This paper reports an experimental and numerical study of micro-contact enhanced thermoelectric cooling of a 5kW/cm2 hotspot on a SiC substrate, demonstrating a “world record” 12K temperature reduction for such high flux, using a commercial thermoelectric module. Moreover, using the validated numerical model, it is predicted that a 5kW/cm2 hotspot could be cooled by up to 30K using an optimized micro-contact and substrate geometry.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
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