STEP BUNCHING INDUCED BY 7X7 SURFACE RECONSTRUCTION ON VICINAL SI(111)

Faceting structure with step bunching and faceting dynamics induced by 7 X 7 surface reconstruction on vicinal Si(111) is studied by Monte Carlo simulation, with the use of the extended TSK (terrace step kink) model to take reconstruction into account. The attractive interaction between neighboring reconstruction units induces the faceting structure in the thermal equilibrium. The calculated local vicinal angle in the step bunching region becomes independent on the global vicinal angle, and it increases as the temperature decreases due to the suppression of the entropy effect. From the simulation of quenching; it is found that the reconstructed (111) facets arise from multiple nucleation of the critical size of reconstruction units and grow via both reducing of the step spacing in step bunches and the rearrangement of a step among step bunches. The calculated results qualitatively explain the observed behavior.