Effect of tunneling current on the growth of silicon islands on Si(111) surfaces with a scanning tunneling microscope

Abstract

The early-stage growth rate of a silicon island on a Si(111) surface at the center of the interaction between a sample and the tip of a scanning tunneling microscope (STM) was defined as a function of the tunneling current. The tunneling current dependence of the rate has a maximum at 0.3 nA, and the decrease of the rate at tunneling currents above 0.3 nA was related to the effect of electron flow on atom transfer by field-induced directional diffusion. The early-stage growth rate was about three times higher than the late-stage growth rate, which was almost independent of the tunneling current. The results suggest that atom transfer by field-induced diffusion on the sample surface was gradually substituted by atom transfer from the STM tip by field-induced silicon atom re-evaporation as the island grew from 0 to about 12 nm in height.