Dimer-vacancy defects on Si(1 0 0): The role of nickel impurity

Abstract

Using scanning tunneling microscopy, x-ray photoelectron spectroscopy, and low-energy electron diffraction, we have studied clean and Ni-containing Si(1 0 0) surfaces and shown that the Ni contamination can easily appear at the Si(1 0 0) during its annealing at high temperature (1230 °C) because of migration of this impurity from heated parts of the sample holder, even though they are nominally Ni-free. The difference of dimer-vacancy (DV) defects, which are common features of Si(1 0 0), and their patterns on both surfaces is examined. It is also found that the density of DV defects on the Ni-contaminated surface is proportional to the number of Ni atoms. The analysis indicates that the fully saturated DV structure, i.e., Ni-induced Si(1 0 0)(2 × n) phase contains one metal atom per defect. The findings are valuable for constructing atomic models of defects on the Si(1 0 0) as well as preparation of clean Si(1 0 0) substrate and monitoring the Ni segregation on its surface. In addition, the results can be useful for Ni silicide metal-contact formation in metal-oxide-semiconductor field-effect transistor technology.”