Dislocation Etch Hillock Formation in White Tin Single Crystals

Abstract

The mechanism for producing pyramidal etch hillocks at the sites of dislocation on the {001} surface of white tin is studied. The hillock formation results from the etch resistant materials existing at the dislocation sites on the crystal surface. These materials come from (1) the segregation of impurities contained in the crystal itself along the dislocation lines, and (2) the precipitation of copper or silver atoms contained in the etching solution at the clean dislocation sites. The role of impurities to produce hillocks is demonstrated and the mechanism for the development of hillocks is derived from the nature of dissolution of the {101} surface enclosing hillocks. Application of this mechanism to another crystal is suggested.