Kinetics of transformation of the atomic step bunches shape under electromigration conditions on the Si(001) surface

Abstract

The quality of the epitaxial structures is significantly influenced by both the initial surface morphology and its transformation during growth. One of the phenomena of surface roughness of silicon occurring during annealing, growth, exposure to electric current, and adsorption of foreign material is the formation of step bunches. The paper presents experimental studies of the transformation kinetics of an atomic step bunches shape on the Si(001) surface that were carried out under electromigration conditions when heated by a constant electric current down the steps in the temperature range of 1000–1150 °С. The samples were annealed in an ultra-high vacuum chamber of a reflection electron microscope, followed by quenching to room temperature. The dependence of the average distance between steps on the number of the bunch steps was observed using an atomic force microscope under atmospheric conditions. It was found that the experimentally obtained dependence obeys a power law (l ∝ Nα), where α varies from –0.68 to –0.36. The study confirmed the change in the elastic interaction potential of steps in bunches with the increase in temperature. The results of the work advance understanding of a bunching process of Si(001) at elevated temperatures.