Spin coating is widely used to deposit uniform thin films, typically <10nm. An excess amount of a solution is applied to a substrate which is then rotated to high speeds in order to spread the liquid evenly over the surface by centrifugal force. Spin coating has been widely used for several decades in photolithography, to deposit photoresist on silicon wafers, and the scope has been extended in recent years to chemically engineering the interface of support and solution to obtain specific structural order in the deposited thin films .
Several important factors influence film deposition, including viscosity of the deposited solution and spin speed for example. Surface wettability also plays an important role and can be controlled with routine plasma cleaning of the substrate prior to deposition. Henniker’s HPT-100 and HPT-200 bench-top plasma systems are widely used for this purpose to achieve clean, contamination free substrates prior to spin coating.