Nanorough silica coatings by chemical vapor deposition

Abstract

Control over the growth of nanoscale roughness on surfaces and interfaces is critical for applications ranging from tunable wettability to anti-reflective coatings. Herein, we investigate the growth of nanoscale roughness on silicon substrates. Nanoscale roughness is introduced by chemical vapor deposition (CVD) of tetraethoxysilane under mild conditions and quantified by scanning force microscopy. We study the dependence of nanoroughness on the surface properties of the substrate before CVD, in particular on annealing and plasma cleaning, while taking an untreated substrate as reference. Nanoroughness is highest on annealed samples and always increases over longer CVD time. Furthermore, we report the time-dependent growth of the thickness of the silica layer. These results contribute to understanding of the role of surface pretreatment in the context of growing silica on a substrate.