Atomically straight steps on vicinal Si (111) surfaces prepared by step-parallel current in the kink-up direction

摘要

We demonstrate that annealing of a vicinal Si(111) surface at about 800 Cwith a direct current in the direction that ascends the kinks enhances theformation of atomically straight step edges over micrometer lengths, whileannealing with a current in the opposite direction does not. Every straightstep edge has the same atomic configuration U(2,0), which is useful as atemplate for the formation of a variety of nanostructures. A phenomenologicalmodel based on electromigration of charged mobile atoms explains the observedcurrent-polarity dependent behavior.