STM PROFILOMETRY OF LOW-LOAD VICKERS INDENTATIONS IN A SILICON CRYSTAL

Scanning tunnelling microscope (STM) images of low-load (15-50 gf) Vickers diamond pyramid indentations in a (111) surface of a p-doped single crystal of silicon have been obtained. From these, information such as the surface profile around a residual indentation, the lengths of its diagonals, its depth, the angles between its face/pyramidal edge and the undisturbed indented surface, and the volume of material within the pile-up region (i.e. above the original indented surface), has been obtained. In some cases, the volume of the piled-up material has been found to be over 80% of the residual indentation. The experimental findings have been discussed in the light of the existing theories of indentation and the process of elastic recovery.