Papers by Author: Y.Q. Wu

Abstract: This paper reports the effect of nanogrinding conditions on the formation of subsurface structures of monocrystalline silicon (100) substrates. It was found that the amorphization and the transformation of high pressure phases were related to the grit depth of cut employed in nanogrinding. The formation mechanisms were found to be different from those previously reported from the nanoindentation studies.

Abstract: In this work, deformation of monocrystalline silicon (Si) under nanoscratching was investigated using transmission electron microscopy (TEM). The results indicated that no fracture occurred during nanoscratching with loads ranging from 1 to 6 mN. The damaged regions induced by nanoscratching included an amorphous Si region and a damaged crystalline Si region. Detailed TEM analyses revealed that at the lowest load of 1 mN no dislocation was observed in the damaged crystalline region, and only stacking faults were observed at the boundary between the damaged crystalline Si and amorphous Si. Dislocations started to nucleate along (111) planes and penetrated into the bulk Si when the normal load was increased to 2 mN and above. Defects perpendicular to the scratched surface were initiated when the load was greater than 4 mN. The density of dislocations also increased rapidly with the increase of the applied load.