Embedded Microjets for Thermal Management of High Power-Density Electronic Devices

With current trends toward increased power in smaller devices and packages, the search continues for high-performance thermal management solutions for MOSFETs, high-electron mobility transistors, and other power electronics. Microjet impingement cooling has been shown to produce high heat transfer capabilities for electronics cooling. In this paper, microjets based on well-studied geometries were embedded within the substrate of a heat-producing device, removing several layers of thermal resistance typically found in advanced packages. In contrast with competing liquid cooling solutions that use expensive materials and processes, industry-standard silicon microfabrication techniques were used to build a low-cost microjet cooler. Numerical analysis of the embedded microjet device showed average heat transfer coefficients greater than 250 kW/m
²
· K and low peak temperature rises in high power-density devices. Using an innovative micro-Raman thermography technique, experimental measurements with a 1-μm spatial resolution were taken, supporting the numerically predicted heat transfer coefficients on a device with a heat flux of over 5 kW/cm
²
and a temperature rise of 46 °C. As devices continue to become miniaturized, both low-cost embedded microjet cooling technology and micro-Raman thermography may play a vital role in the design, operation and evaluation of advanced high power-density electronics.