Critical Terrace Width for Vacancy Islands Nucleation on Wide Terrace of Silicon (001) Surface under High Temperature Annealing

Abstract

The process of forming a system of concentric steps on the silicon (001) surface, separated by wide terraces, has been studied in situ by means of ultrahigh vacuum reflection electron microscopy. The possibility of controlling terraces width by compensating atoms sublimation by an external atoms flux has been shown. The temperature dependences of the critical diameter of the terraces for the nucleation of a new vacancy island have been measured in along and across dimer row of superstructure 1 × 2 direction in the temperature range 1 070-1 160 °C. The increase in the critical diameter with increasing atomic flux has been demonstrated. The anisotropy of a critical terrace size decreases with an increase in temperature independently of deposition flux and the critical size of the terrace along and across the dimer row coincides with an error accuracy at temperatures above 1 125 °C. The kinetics of vacancy islands nucleation has been determined in the framework atomic nucleation theory, and the values of the critical nucleus, the binding energy in the nucleus and the difference of diffusion energies along and across dimer rows have been estimated.