Séminaires > Multi-scale thin film growth simulation via kinetic Monte Carlo simulation
Date : 10h30
Lieu : C21, Orbigny
Résumé :
Nowadays, research in the field of nanoscale thin film growth is exceptionally active as new emerging fields related to plasmonics or energy-harvesting applications rely on a 3D integration of nanoscale layers into complex architectures for the next generation of electronic devices. It is well established that there is a complex dependence of the film microstructure and the resulting properties on the deposition conditions (i.e. the kinetic energy of the deposited particles, substrate temperature) and on the chemical interaction with the substrate (surface reactivity, adatom mobility, intermixing).
Inthis seminar I will address fundamental questions on the complex interplay between deposition process parameters, the evolution of ultrathin films morphology, alloying formation, and stress generation occurring during the initial stage of the growth. To this end I will present a multi-level methodology that has been developed in the Pprime Institute which combines multiscale kinetic Monte Carlo (kMC) simulations, atomistic calculations and real-time experimental characterizations.
In the first part of this talk I will introduce the main ingredients needed to perform multiscale (kMC) simulations of the overall physical deposition process (PVD) which is a deposition process based on physical process. In this respect I will detail, in the case of Cu and TiN, the deposition and the diffusion model that we have developed in house. The deposition model considers the angular and energy distribution of the incoming particles, as provided by SRIM and SIMTRA calculations. Beside deposition and diffusion events, atomistic mechanisms relevant to growth under energetic deposition conditions, such as re-sputtering, directionally-induced surface diffusion and bulk defect creation, have been explicitly considered. Within the diffusion model, the anisotropy of adatoms surface diffusion is taken into account as well.
In a second step I will present several simulation results showing the influence of the deposition parameters on the resulting thin film properties in the case of coper and titanium nitride thin film. For instance, the influence of the deposition angle on the resulting columnar nitride thin film growth will be highlighted. We will also give evidence of a self-organized nano-structuration of Cu layers obtained for an incident angle of 85° with a preferential orientation of patterns which depends on the temperature. The influence of surface reactivity will also be discussed thanks to in-situ stress measurement DFT and MD simulations results.