Embedded two-phase cooling of high heat flux electronics on silicon carbide (SiC) using thin-film evaporation and an enhanced delivery system (FEEDS) manifold-microchannel cooler

Abstract

This work presents experimental results of a two-phase, embedded cooling system for high heat flux electronics on silicon carbide (SiC) substrates. The system uses a thin-Film Evaporation and Enhanced fluid Delivery System (FEEDS) Manifold Microchannel (MMC) cooler. SiC-based high power electronics are gaining momentum due to SiC's desirable electrical and thermal performance. For example, single-crystalline SiC shows thermal conductivities exceeding 350 W/m-K, which is several times higher than that of silicon. Accordingly, FEEDS MMC coolers were fabricated and embedded onto SiC substrates by etching deep-trench (with aspect ratios around 5) microchannels into the substrates. Previous studies on FEEDS MMC on silicon have reached high heat fluxes above 1 kW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 45% vapor quality with R245fa at 30oC saturation temperature. In comparison, the SiC devices here show better thermal performance, exhibiting cooling of 1 kW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and up to -85% exit vapor quality. The system was also tested with single-phase mode to validate system performance via comparison to CFD simulations, before two-phase tests were performed. Microfabrication of the SiC channels are also discussed.