Sb adsorption and desorption pathways on (2 × 1) and c(4 × 4) reconstructed Si(0 0 1) surfaces

The role of initial surface reconstruction on the kinetics of heteroepitaxial growth of Sb on Si(0 0 1) surface is elucidated. The adsorption and desorption of Sb, from the clean-(2 × 1) and c(4 × 4) reconstructions of Si(0 0 1) surface, is investigated by in situ auger electron spectroscopy (AES) and low energy electron diffraction (LEED). Sb is adsorbed at room-temperature (RT) onto clean-(2 × 1) and c(4 × 4) reconstructed Si(0 0 1) surfaces at a base pressure of 3 × 10−11 Torr. At the very low flux rates adopted (0.06 monolayer/min), Sb grows epitaxially at RT and forms a (1 × 1) surface phase for coverages greater than 1.0 monolayer (ML) on both the (2 × 1) and c(4 × 4) surfaces. Residual thermal desorption studies done on these RT-adsorbed systems are observed to adopt different pathways. The ‘(2 × 1) case’ results in an intermediate novel 0.6-ML (8 × 4) phase, while the ‘c(4 × 4) case’ directly yields the 0.25-ML c(4 × 4) phase. The 0.25-ML Sb covered c(4 × 4) obtained from the Si(0 0 1)-c(4 × 4) phase is observed to be sharper than that obtained from the (2 × 1) reconstructed surface. Upon complete Sb desorption both the cases result in the clean Si(0 0 1)-(2 × 1) surface. The difference in desorption pathways is related to the Sb monolayer formation.