Influence of electromigration field on the step bunching process on Si(111)

摘要

We managed to isolate the effects of electromigration in the dynamics of the step bunching process on the vicinal Si(111) surface. Unlike in conventional experiments, we conducted the annealing of Si(111) in a specially engineered setup enabling independent temperature control and an in-plane electric field. The primary result is that the step bunching process continues to take place at relatively low applied electric fields and ceases below E=0.5 V/cm. Reduction in the electric field results in a significant expansion of step bunches width and elongation of the crossing steps running along the terraces. A theoretically predicted systematic increase in the number of crossing steps with reduced electromigration force has been experimentally observed. A distinct difference has been observed in the way that (1 × 1) to (7 × 7) phase transition manifests itself on the Si(111) surfaces with a misorientation toward the [112] and [112] directions.