Doping by metal-mediated epitaxy: Growth of As delta-doped Si through a Pb monolayer

In molecular-beam epitaxy a monolayer of Pb on the Si~111! surface induces single-crystal growth at temperatures well below those required for similar growth on a bare surface. We demonstrate that the suppression of dopant segregation at the lower temperatures attainable by Pb-mediated growth allows the incorporation of As donors at concentrations reaching a few atomic percent. When Pb and Si are deposited on an As-terminated Si~111! substrate at 350 °C, the Pb segregates to the surface without doping the Si film while the As is buried within nanometers of the substrate–film interface. The resulting concentration of electrically active As, 1.8310 cm, represents the highest concentration of As donors achieved by any delta-doping or thin-film deposition method. © 2001 American Institute of Physics. @DOI: 10.1063/1.1352692#