SILICON (111)−7 STRUCTURE OBTAINED BY CLEAVAGE AT ROOM TEMPERATURE

Abstract
It has been found that the Si (111)−7 structure can be observed within a few seconds of cleavage at room temperature. High‐temperature heat treatment of the surface, previously thought to be essential to produce the structure, is not required. Auger spectra of both the (7×7) and (2×1) structures obtainable on room‐temperature cleavage are identical. To obtain the ``cold'' (7×7) structure, the crystals have been annealed at some period (up to several days) prior to cleavage. The cleavage must be characterized by minimal pressure rise and only minor fracture marks. If impurities are at all involved in the (7×7) structure, these results show that the only ones required are those inherently in the cleavage surface.