Post-Doctoral fellowship in multi-scale modeling of the growth of polycrystalline thin films.

The candidate will extend the current kMC code (developed by the group), dedicated to the simulation of a 3D growth
of Cu/Cu(001) under energetic conditions, to the case of Cu/substrate interface of different chemistry, and to polycrystalline systems in order to account for the issue of GB formation and grain misorientation. First, the candidate will become familiar with the current code, based on a single rigid lattice, and will study the dewetting of Cu(001) films.

Subsequently, the growth of polycrystalline films will be approached through the implementation of the multi-lattice kinetic Monte Carlo code (mn-kMC). This evolution of the code could be achieved by using several rigid networks following the work of Huang1

. Particular emphasis will be placed on the dynamics of GB formation and the role of energetic species on metal and/or silicon diffusion. Also, defect annihilation at the free surface and at the GB will be implemented leading to thin film stress relaxation2.

This will give a comprehensive picture of the microstructural changes of polycrystalline films, and will allow for the identification of the origin of the structural and morphological evolution. Beyond this, the final objective is to address the origin and evolution of intrinsic stress during thin film growth using off-lattice kMC.
Therefore, the second part of the work will be dedicated to investigate at atomic scale, the crucial role of GBs on the dynamic stress evolution (generation and/or relaxation) during growth by means of a comprehensive description of the diffusion mechanisms near GBs. One suitable approach is the combination of the developed mn-kMC code with kinetic Activation- Relaxation Technique (k-ART) 3

code, which is an off-lattice, self-learning, on-the-fly
identification and evaluation of activation barriers. The fulfilment of this objective will be facilitated thanks to close
collaboration with the developper of the k-ART code, Pr N. Mousseau (University of Montreal, Canada).
The outcome will be benchmarked against experimental validations (structural, electrical and optical layer properties)
thanks to the unique palette of in situ and real-time diagnostics available at Pprime Institute

(1) H. Huang and L. G. Zhou, “Atomistic simulator of polycrystalline thin film deposition in three dimensions”, Journal of Computer-Aided Materials Design 11, 59 (2004). 
(2) E. Chason ,P. Guduru, “Tutorial: Understanding residual stress in polycrystalline thin films through real-time measurements and physical models”, Journal of Applied Physics 119, 191101 (2016)./ E Chason, M Karlson, J. J Colin, D Magnfält, K Sarakinos, G Abadias, “A kinetic model for stress generation in thin films grown from energetic vapor fluxes”, Journal of Applied Physics 119, 145307 (2016).
(3) F. El-Mellouhi, N. Mousseau, L. J. Lewis, “Kinetic activation-relaxation technique: An off-lattice self-learning kinetic Monte Carlo algorithm”, Physical Review B 78, 153202 (2008). / 0scar A. Restrepo, N. Mousseau, F. El-Mellouhi, O. Bouhali, M. Trochet, C. S. Becquart, “Diffusion properties of Fe–C systems studied by using kinetic activation–relaxation technique”, Computational Materials Science 112, Part A, 96 (2016). / G. K. N’Tsouaglo, L. K. Béland, J. – F. Joly, P. Brommer, N. Mousseau, P. Pochet, “Probing potential energy surface exploration strategies for complex systems”, Journal of Chemical Theory and Computation 11, 1970 (2015).