FisMat2017 - Submission - View

Abstract's title: Atomic scale investigation of local strain effect on the primary stages of silicon oxidation process using a coupling between Activation Relaxation Technique and first principles calculations
Submitting author: Nicolas Salles
Affiliation: University of Nova Gorica
Affiliation Address: Vipavska 11c SI-5270 Ajdovščina Slovenia
Country: Slovenia
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Nicolas Richard, CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon , France Normand Mousseau, Université de Montréal, Département de Physique, C.P. 6128, succursale Centre-ville H3C 3J7 Montréal Canada Anne Hémeryck, LAAS CNRS, Université de Toulouse, CNRS, Toulouse, France

The SiO2/Si interface is still a crucial issue in silicon- based nanotechnology, since the electronic properties of achieved devices are directly dependent of the quality of this interface. In the context of extreme miniaturization, the control of nanoscale structure and defects formation during the elaboration process are thus major challenges for the microelectronics industry. 


In the presentation, we focus on how the strain evolution drives the nanoscale mechanisms of the first steps of the oxidation process thanks to an atomic scale approach coupling Density Functional Theory (DFT) Calculations and Activation Relaxation Technique-nouveau (ARTn). The Activation Relaxation Technique nouveau (ARTn) enables to explore the potential energy surface (PES) and to determine various transition states, i.e. the different possible configurations and their corresponding energy barriers. 


We presente the atomic oxygen diffusion mechanisms obtained with ARTn-VASP from the above adsorbed states, highlighting a great diversity of final configurations and a wide spectrum of activation energies. For example, we observe that at this step of oxidation, atomic oxygen lateral diffusion at the interface is more favourable than deeper into the bulk. We also observe a progressive reconstruction of the silicon substrate at the SiO2/Si interface as Si-Si dimers are formed as long as the oxidation progresses, allowing to reduce the misfits at the interface. Activation barriers allow to identify kinetically favourable events for the oxidation progress. 


The ARTn-VASP coupling appears as an original and powerful tool to highlight atomistic events encountered during silicon oxidation, even involving complex atomic modification appearing as key phenomenon toward silica amorphisation and defect generation at the SiO2/Si interface.