Coarse-grained approach to amorphous and anisotropic materials in Kinetic Monte Carlo thin-films growth simulations: a case study of TiO2 and ZnO by Plasma Enhanced Chemical Vapor Deposition

TL;DR

This paper presents a coarse-grained kinetic Monte Carlo simulation method that models the growth of amorphous TiO2 and polycrystalline ZnO thin films during plasma-enhanced chemical vapor deposition, capturing morphological and structural features.

Contribution

It extends existing simulation approaches to accurately reproduce both amorphous and anisotropic crystalline film growth, including texture evolution and grain competition.

Findings

Simulation results agree with experimental XRD, AFM, and SEM data.

The method captures morphological scaling and texture evolution.

Growth conditions influence grain texture and film morphology.

Abstract

The growth of amorphous TiO2 and anisotropic-polycrystalline ZnO thin-films is studied by means of coarse-grained three-dimensional kinetic Montecarlo simulations under conditions typically encountered in Plasma Enhanced Chemical Vapor Deposition experiments. The approach developed considers fluctuations in the activation energy for surface diffusion of the coarse particles that are calculated on-the-fly and depends on the mesoscale local morphological/structural landscape. The basis of this approach --which is known to work well to simulate the growth of amorphous materials using a much simpler cubic grid-- has been extended in this work to reproduce not only the morphological characteristics and scaling properties of amorphous TiO2 but also the growth of polycrystalline ZnO with a good approximation, including the evolution of the film texture and textured-grain competition during growth and its dependence on experimental conditions. The results of the simulations have been compared with available experimental data obtained by X-Ray Diffraction, analysis of the texture coefficients, Atomic Force Microscopy and Scanning Electron Microscopy