关键词: 薄膜, 分子动力学, 力学性能, 纳米压痕, 原子力显微镜

Abstract: Nanoindentation tests performed in an atomic force microscope have been utilized to directly measure the mechanical properties of single crystal copper thin films fabricated by the vacuum vapor deposition technique. Nanoindentation tests are conducted at various indentation depths to study the effect of indentation depths on the mechanical properties of thin films. The elastic modulus of the single crystal copper film at various indentation depths is determined as 67.0 Gpa±6.9 Gpa on average which is in reasonable agreement with the results reported in literature. The indentation hardness constantly in-creases with decreasing indentation depth, indicating a strong size effects. In addition to the experimental work, molecular dynamics simulations of nanoindentation process have been conducted to elucidate the mechanics and mechanisms of na-noindentation of thin films. MD simulations results show that due to size effect the plastic deformation via amorphous trans-formation is more favorable than via the generation and propa-gation of dislocations in nanoindentation of single crystal cop-per thin films. Simulations results also elucidate the reason of size effects from the atomistic point of view.

Key words: Thin film, Atomic force microscope, Mechanical properties, Molecular dynamics, Nanoindentation