FEA study on nanodeformation behaviors of amorphous silicon and borosilicate considering tip geometry for pit array fabrication

In order to predict the nanodeformation behaviors (piling-up, sinking-in, and elastic recovery) of hard-brittle materials such as amorphous silicon and Pyrex 7740 glass (borosilicate) indentation simulations were performed for various tip radii (40, 100, 200 nm), half-angle of conical indenter (55, 60, 65°), and indenter geometries (conical, Berkovich, spherical) by the numerical method with ABAQUS finite element software package. The result for conical indenter showed the smallest elastic recovery. The amorphous silicon showed higher pile-up than the Pyrex glass 7740 because it has a larger value of E/σy. It was also observed that the height of pile-up decreased with increasing amount of the elastic recovery. For a given indentation depth, the applied load and elastic recovery increased with a tip radius and half-angle due to the increase of the contact area. In addition, a larger plastic zone size formed with shaper indenter due to the higher stress concentration exerted.