Fabrication of 2D TiO2 Nanopatterns by Plasma Colloidal Lithography

The present study investigates the capability of plasma colloidal lithography technique consisting on three fabrication steps, colloidal mask deposition, thin film deposition with colloidal masks and colloidal mask lift off, to fabricate 2D patterns of TiO2 on silicon substrate. For the plasma assisted thin film deposition step, we used reactive high power impulse magnetron sputtering, a technique known to yield highly compact thin films with good control of composition and crystallinity. The fabricated 2D nanopatterns were investigated by atomic force microscopy and scanning force microscopy. Highly ordered 2D crystal array of TiO2 triangular islands with the maximum height of about 10 nm were obtained independently of the TiO2 thin film deposition time (thickness). The relatively low value of TiO2 pattern height is explained by the shadow effects of the mask, a large number of particles from the gas phase contributing on the film deposited on the mask, until complete filling of the void spaces between nanoparticles of the mask.