TEM and HRTEM Observations of Microstructural Change of Silicon Single Crystal Scratched under Very Small Loading Forces by AFM

The microstructural change of the surface and the subsurface regions of a Si single crystal (Si(100)) after scratching tests under very small loading forces was investigated. First, the scratching tests were carried out using an atomic force microscope (AFM). Then, the profiles of those wear traces which were generated by the scratching tests were observed using a transmission electron microscope (TEM). TEM observations revealed that dislocations were activated in the sub-surface within less than 100 nm depth from the surface of the wear traces when the loading force was higher than 5 mN. When the loading force was higher than 20 mN, patches of amorphous Si was observed occasionally at the surface of the wear traces. High-resolution TEM (HRTEM) observations revealed that a dislocation introduced by the scratching test was a total dislocation with Burgers vector of 1=2h110i. [doi:10.2320/matertrans.MRA2008017]