Integrated Analyses on Creation-Structure-Deformation of Functional Thin-Film Materials Using Molecular Dynamics Method and Assessment of Their Integrity

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Thin-film coated materials have a wide application in their functional usages. It is required, however, that the integrity should be guaranteed during their engineering applications, In this project, systematic analyses have been made on variations in microstructures of coated thin-films and substrates during coating processes as well as their properties of the subsequent deformation associated with the microstructural variations.By an RF sputtering procedure, various thin-film coated materials were prepared by coating aluminum metal, alumina (Al_2O_3) and silicon carbide (SiC) ceramics on borosilicate glass substrates. Mechanical properties of the prepared materials were investigated, and investigated properties are as follows, surface roughness, porosity, hardness of coated films and bending strength of coated materials. Interrelations among these properties were clarified including the relations with coating conditions.A new procedure using molecular dynamics (MD) was established so … More that integrated analyses could be executed on sputtering processes, the resultant film-structures as well as the strength properties of coated materials. The sputtering of Al on silicon (Si) substrate was analyzed by using the proposed procedure. The occupancy ratio of atoms in the coated film was found to increase for larger incident energy. The tensile strength of Al coated material was examined by loading in the direction parallel to the interface between film and substrate. The analytical result showed the reduction in strength caused by the pore formation during coating process. It was clarified that the material coated by the film with lower density and higher porosity had lower resistance to the indentation deformation. By comparison between analytical and experimental results, it was concluded that the proposed MD procedure was effective to the analyses of processing, structure and deformation of thin-film coated materials and was suggested to be applicable to the integrity evaluation of such materials. Less