Micro/nano hierarchical structure in microchannel heat sink for boiling enhancement

Uniform SiNW structures were fabricated for the first time on the top, bottom and sidewall surfaces of microchannel heat sinks by using a two-step electro-less etching process. The micro/nano hierarchical structure yields superior boiling heat transfer performance. Its maximum heat flux is improved by 150% over the microchannel-only heat sink and 400% over a plain silicon surface. These results provide a new insight into the boiling mechanism for microchannel heat sinks using hierarchical structures.