Atomistic model of ultra-smooth amorphous thin film growth by low-energy ion-assisted physical vapour deposition

The growth of ultra-smooth amorphous thin films induced by low-energy (below 1 keV) ion-assistance processes is studied. The relative contribution of ion-induced smoothening effects is analysed by means of a Monte Carlo model and experimental data. In general, highly rough granular or ultra-smooth (with roughness below one monolayer) films are produced depending on the competition between surface shadowing and ion-induced adatom mobility and sputtering. The ultra-smooth growth regime is experimentally and theoretically consistent with the Edwards–Wilkinson growth mode, which is related to the ion-induced enhancement of surface mobility. Overall, the framework and the fundamentals to analyse this type of growth are developed and discussed.This work has been financially supported by grants CSD2008-00023, MAT2010-21228, and MAT2010-18447 (MICINN, Spain); FIS2012-38866-C05-05 (MECO, Spain); S2009/PPQ-1642AVANSENS (CAM, Spain) and projects P09-CTS- 5189, TEP5283 and P10-FQM-6900 (Junta de Andalucía, Spain). ARC acknowledges funding from SFRH/BPD/74095/2010 (Portugal).Peer Reviewe