Atomic-scale observation and control of the reaction of phosphine with silicon

Abstract

The ability to identify and control the pathway by which chemical reactions occur at the level of individual atoms will be of enormous benefit in the coming age of nanotechnology. Here, we present a detailed atomic-resolution scanning tunneling microscopy (STM) study of one such pathway: the adsorption, surface diffusion and dissociation of phosphine (PH3) on silicon (001). We show that PH3 dissociates on Si(001) to produce PH 2 + H, PH + 2H and P + 3H moieties. In addition, we show that PH 2 molecules are readily able to diffuse on Si(001) at room temperature, resulting in the formation of hemihydride dimers on low dosed Si(001) surfaces. In addition we show that control over the processes of diffusion and surface incorporation can be achieved using STM-based hydrogen lithography; a technique that is now used in many STM laboratories. © 2006 The Surface Science Society of Japan.