Nanosecond laser structuring for enhanced pool boiling performance of SiC surfaces

Silicon carbide (SiC), which has a wide bandgap and superior material properties, offers higher efficiency than conventional silicon in high-power and high-frequency semiconductor applications. In this study, the thermal management of SiC devices was explored through direct liquid cooling with laser-structured heat sinks. Pyramid- structured fin arrays were fabricated directly onto SiC substrates via laser structuring, and their boiling heat transfer performance was investigated through pool boiling experiments in a 5 degrees C subcooled condition. Laser structuring not only enhanced wettability due to oxidation but also facilitated nucleation through the laser- induced crevices. The oxidized surface created by the laser exhibited increased hydrophilicity, with a significant decrease in contact angle from 57 degrees degrees to 0 degrees. degrees . In the pool boiling experiments, these crevices played a crucial role in enhancing the heat-transfer coefficient (HTC) at low heat fluxes (5-40 W/cm2), 2 ), which promoted nucleation, resulting in the formation of very small and rapid bubbles. At heat fluxes above 180 W/cm2, 2 , the large surface area provided by the height of the fin structures further contributed to enhancing the HTC. The sample with the highest performance enhancement exhibited an 114 % increase in critical heat flux and a remarkable 393 % increase in the HTC compared to before laser structuring.