The local electronic properties and formation process of titanium silicide nanostructures on Si(001)-(2 × 1)

Titanium silicide island formation on an Si(001)-(2 × 1) surface was studied by means of scanning tunneling microscopy (STM) in situ at high temperature. Just after the start of annealing at 873 K, homogeneous nucleation occurs on the terrace, while preferential growth at the step edges was observed upon prolonged annealing. As the titanium silicide islands grow, multiple steps are formed nearby. The island size distribution was analyzed at several temperatures. Two types of TiSi2 structures, namely C49 and C54, were identified from the scanning tunneling spectroscopy (STS) spectra, in accordance with first-principles calculations. There was a critical island size for the transformation of C49–C54.