Active hot spot cooling of GaN transistors with electric field enhanced jumping droplet condensation

Mitigating heat generated by hot spots inside of power electronic devices is a formidable obstacle to further increases in power density. This paper presents the first demonstration of active cooling for hot spots via jumping droplet condensation. This newly discovered phase change cooling mechanism comprises 10 to 100 μm sized droplets leaping from a cold superhydrophobic surface onto a hot GaN transistor and efficiently transferring heat via evaporation. After discussing how electric fields can enhance this process, observations from cooling GaN transistors with this method are outlined. Experimental measurements demonstrate increased cooling rates and steerable heat transfer through the application of electric fields.