STEP STRUCTURE TRANSFORMATION OF SI(001) SURFACE INDUCED BY CURRENT II

The domain conversion mechanism on Si(001) surface induced by DC current and the recovery mechanism of a minor domain in the thermal relaxation are investigated. The step kinetics is treated by developing the BCF theory to take account of the following four effects: contribution of the drift flux of adatoms, anisotropy of a diffusion constant, repulsive interaction between steps, and four kinds of capture rates of adatoms at each step edge S(a) or S(b) from the upper or lower side. The time evolution of step configuration is calculated numerically. The Schwoebel effect can explain the observed difference between the spreading velocities of 1 x 2 and 2 x 1 domains, induced by DC current. In this domain conversion, initially formed step pairs have a tendency to form bunching structure for the driving force in the step-down direction. The thermal relaxation is caused by the repulsive step-step interaction, but the Schwoebel effect influences the final step configuration and brings about the dominance of 1 x 2 domain rather than 2 x 1 domain.