Near-junction cooling for next-generation power electronics

This article focuses on chip-scale single-phase cooling for high heat flux and high temperature power device operation. This technology is focused on future wide band-gap semiconductors, which are expected to survive harsh environments. To this end, strategies for near-junction cooling of vertical current power electronics devices are briefly reviewed, and two chip-scale coolers are experimentally investigated. Using single-phase water at an inlet temperature of 50 degrees C, a 40 mm x 20 mm straight microchannel (quantity 200, 38 mu m x 313 mu m) cooling chip is shown to dissipate up to 127.5 W/cm(2) over a 1 cm(2) area with a pressure drop of 40.2 kPa at 100 ml/min. A second 75% downsized 20 mm x 10 mm cooling chip based on a unique 500 mu m x 500 mu m unit cell microchannel plus jet impingement array architecture is then introduced. At the same inlet temperature and in single-phase operation, this chip-scale cooler is shown to dissipate up to 1.02 kW/cm(2) over a 0.25 cm(2) area. A maximum average heat transfer coefficient of 120.2 kW/m(2)K and a pressure drop of 81.2 kPa is further established at a 450 ml/min fluid flow rate. The unit cell jet impingement-based design is shown to additionally support average heater temperatures of 177.1 degrees C. Such technologies are anticipated to enable a 5-to-10-fold reduction in power package size when compared with traditional remote cooling strategies.