Tailored nanostructured titania grown on titanium micropillars with outstanding wicking properties for thermal management of microelectronics devices

This paper discusses a novel thermal management approach using nanostructured titania formed on high-aspect ratio micromachined titanium structures. A recently developed dry etching technology, with etch rates of more than 2 µm/min, enables bulk micromachining of titanium using an inductively coupled plasma to define high aspect ratio structures. This technology allows for the development of three-dimensional architectures through the successive stacking and bonding of through-etched titanium foils. Nanostructured titania was formed on high aspect ratio titanium structures using a simple technology involving oxidation in aqueous hydrogen peroxide followed by annealing. These high aspect ratio structures with nanostructured titania surface and titanium core have excellent hydrophilic properties which bodes well for thermal management applications. Compared to those using copper based wick materials, heat pipes using nanostructured titania/Ti ones have better capillary speed characteristics which decays at a slower rate.