Aerosol deposition of dense alumina coatings on micropillar-patterned Si substrates

Abstract

Fabricating dense ceramic layers without cracks is challenging, especially on structured surfaces and under low process temperatures. Aerosol deposition (AD) is a promising technique for producing dense ceramic coatings at room temperature. Film formation on smooth and flat substrates by AD has been explored in the field, but deposition on patterned surfaces was rarely studied. In this work, we describe dense alumina coatings deposited on flat and micropatterned silicon substrates using AD. We demonstrate that the patterned substrates with 1–2 μm pillars can reduce or eliminate the formation of horizontal micro-cracks in the coatings. The impact of pillar walls on coating quality and deposition rate diminishes when the pattern size exceeds the powder agglomerate size. The deposited layers cover the substrate patterns completely and give uniform coating surfaces, which opens the way for AD in applications such as hole-filing and 3D micro-energy devices.