Effect of room-temperature adsorption of Sn on Si(100) surface properties

Abstract

The initial steps of ultrahigh-vacuum deposition of Sn on clean Si(100) surfaces have been studied using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES) and photoemission yield spectroscopy (PYS). While the initial 2×1 reconstruction reduces to 1×1 between 0.5 and 1 monolayer (1 ML=6.8×1014 atoms per cm2 along the (100) face of Si), Sn forms a uniform overlayer up to 2 ML and then grows as metallic islands. The ionization energy and work function decrease in parallel, and the largest part of the decrease occurs upon 0.25 ML of Sn. New features start to grow in the band of filled surface states beyond 0.25 ML of Sn. The results are compared to Sn adsorption on cleaved 2×1 reconstructed Si(111).