REFLECTION ELECTRON-MICROSCOPY STUDIES OF THE STEP MEANDERING AND EVAPORATION ON VICINAL SURFACES OF SILICONE

In situ reflection electron microscopy (REM) experiments have been done on the steps of clean Si(111) and Si(100) vicinal surfaces. Under thermodynamic equilibrium conditions, the wandering of an isolated step and of step trains has been analysed at 900 degrees C on (111) vicinals. The step stiffness of an isolated step has been measured (beta approximate to 1 X 10(-10) J m(-1)). From the analysis of terrace width distribution the existence of long-ranged 'energetic' step interactions decaying as A chi(-2) can be established (chi normal distance to the step edge). The value of A is (2.1-3.8) x 10(-30) J m. The mechanisms of adatom supply to a step has been determined, either from the time of formation of a step fluctuation or from the time-correlation of the step positions. In the sublimation regime, the (111) vicinals evaporate by step-flow only whereas the (100) undergo step-flow, and hole nucleation and kinetic roughening. The implications of these different behaviours is discussed.