Evolution of surface morphology of vicinal Si(111) surfaces after aluminum deposition

We have studied changes in surface morphology of vicinal Si(111) surfaces with a miscut of 1.3 degrees in the [(2) over bar 11] direction after Al deposition at elevated temperatures. The clean surface phase separates into a (111)-oriented phase and a stepped phase. Submonolayer Al deposition at 650 degrees C, the normal preparation temperature of the Al/Si(111)-(root 3 x root 3)R30 degrees structure, only induces minor changes in the surface morphology. However, after Al deposition at temperatures above the order-disorder phase transition temperature, the step bunches break apart into a uniform array of single height steps with an average step-step separation determined by the macroscopic miscut. From a quantitative analysis of the amount of meandering of steps and the terrace width distribution, we determined the diffusivity of steps and the strength of the repulsive step-step interaction. The repulsive interaction between steps is enhanced by the Al adsorption compared to both the high-temperature (1 x 1) and (7 x 7) phases of the clean surface. (C) 1998 Elsevier Science B.V. All rights reserved.