Preservation of the Phase Boundary of Si(111)7×7 Structure in Air Studied by Force Microscopy

Abstract

Si(111) surfaces cleaned under ultrahigh vacuum were studied by force microscopy in air. 7×7 domain boundaries associated with the phase transition from 1×1 to 7×7 during cooling were imaged as 1.0∼1.5 Å high protrusions. The morphology was quite consistent with results from in situ techniques. For rapidly quenched surfaces, disordered 1×1 triangles were also seen in the middle of terraces. These structures may be related to the difference in surface atom densities and the difference in reaction to oxygen.