Open AccessTime Invariant Surface Roughness Evolution during Atmospheric Pressure Thin Film Depositions
Author(s) -
Thomas Merkh,
Robert Spivey,
T.M. Lu
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep19888
Subject(s) - surface roughness , invariant (physics) , surface pressure , surface finish , atmospheric pressure , thin film , surface (topology) , atmospheric sciences , materials science , environmental science , computer science , composite material , meteorology , geology , geometry , physics , mathematics , nanotechnology , mathematical physics
The evolution of thin film morphology during atmospheric pressure deposition has been studied utilizing Monte Carlo methods. Time invariant root-mean-squared roughness and local roughness morphology were both observed when employing a novel simulation parameter, modeling the effect of the experimental high pressure condition. This growth regime, where the surface roughness remains invariant after reaching a critical value, has not been classified by any existing universality class. An anti-shadowing growth mechanism responsible for this regime occurs when particles undergo binary collisions beneath the surface apexes. Hence, this mechanism is applicable when the mean free path of the depositing species is comparable to the amplitude of the surface features. Computationally this has been modeled by allowing particles to change direction at a specified height above the local film surface. This modification of the incoming flux trajectory consequently has a dramatic smoothening effect, and the resulting surfaces appear in agreement with recent experimental observations.