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

Abstract

We have studied changes in surface morphology of vicinal Si(111) surfaces with a miscut of 1.3° in the [ 2 ̄ 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°C, the normal preparation temperature of the Al/Si(111)- ( 3 × 3 ) R30° 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 (1×1) and (7×7) phases of the clean surface.