Sublimation of the Si(111) surface in ultrahigh vacuum

Abstract
We investigated sublimation of a Si(111) surface using a 70-μm-wide (111) plane created at the bottom of a crater during ultrahigh-vacuum heating. Step spacing on the plane is determined by nucleation of macrovacancies in the center of the plane while steps move in a step-flow manner. The step spacing is related to the adatom diffusion length and decreases with increasing temperature of up to 1190 °C. Around 1200 °C, the spacing shows a transitionlike behavior and increases to 2.5 times the value at 1190 °C. Step flow is maintained above the step-spacing transition.