透過型電子顕微鏡を用いたナノスケール構造体中の塑性領域に対するその場観察試験手法の開発

摘要

界面と表面が会合する界面端近傍では，変形のミスrnマッチに起因した応力集中が生じる．このため，rn界面端は，塑性変形や破壊の優先的な発生起点になりrnやすい．マクロ材料に対しては，界面端近傍の応力場rnに注目した変形・破壊に関する多くの研究がなされてrnきた．%In order to specify the plasticity of a nanoscale Cu component, we develop a novel experimental method by means of a general purpose transmission electron microscopy (TEM). The characteristic shape of a designed thin specimen, where a Cu film with the thickness of 200 nm is sandwiched by rigid materials (Si substrate and SiN layer), enables us to apply a load near Cu/Si interface edge by an indenter, and prevents buckling due to compressive stress. Continuous in-situ TEM images of the Cu film during deformation are successfully obtained, and the generation and expansion of local plastic region of 10 nm-30 nm are recognized near the Cu/Si interface edge. The yield stress of the plastic region is approximately evaluated to be 200 MPa-400 MPa, which is close to the one obtained by an inverse analysis under a continuum assumption (345 MPa).