Microscopic kinetic mechanism in current-induced conversion on Si(001) vicinal surface

The microscopic mechanism of current-induced domain conversion phenomena on the Si(001) vicinal surface during annealing is studied using the kinetic equation derived by the path probability method (PPM) in irreversible statistical mechanics along with the Monte Carlo simulation. In addition to evaporation, our model takes account of the three effects related to migration of surface atoms: anisotropic migration on the Si(001) 2 x 1 reconstructed surface, the electromigration effect and asymmetry in step kinetics (Schwoebel effect) which takes the difference in the kinetics between two types of steps into account. The numerical calculation of the kinetic equation reproduces the domain conversion when the Schwoebel effect exists. The differences in the movements of two types of steps and the spreading velocities of major domains observed during domain conversion are also shown. The results suggest that the combination of the three migration effects causes the difference in the kinetics of atoms between two types of steps, which leads to the domain conversion. The results of tie Monte Carlo simulation are in good agreement with those of the PPM.