Evolution of surface morphology of vicinal Si(111) surfaces after aluminumdeposition

We have studied changes in surface morphology of vicinal Si(111) surfaces w ith a miscut of 1.3 degrees in the [(2) over bar 11] direction after Al dep osition 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 mor phology. However, after Al deposition at temperatures above the order-disor der phase transition temperature, the step bunches break apart into a unifo rm array of single height steps with an average step-step separation determ ined by the macroscopic miscut. From a quantitative analysis of the amount of meandering of steps and the terrace width distribution, we determined th e diffusivity of steps and the strength of the repulsive step-step interact ion. The repulsive interaction between steps is enhanced by the Al adsorpti on 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.