Crystallographic effect on subsurface damage formation in silicon microcutting

Nanoprecision plunge cutting tests were carried out on single-crystal silicon (0 0 1) samples along various directions at different tool rake angles, and subsurface damage was characterized by cross-sectional transmission electron microscopy and laser micro-Raman spectroscopy. It was found that amorphization, poly-crystallization, dislocation and internal microcracking occurred and these material responses depended strongly on the cutting direction. When cutting in the [ 1   1 ¯   0 ] and [ 0   1 ¯   0 ] directions, deep line defects consisting of microcracks and dislocation groups occurred even when the surface was “ductile”-cut; while for the [ 128   309 ¯   0 ] direction, the damage depth was reduced by a factor of five.