Iron disilicide growth on Si(111): a scanning tunneling microscopy investigation

Abstract The growth of Fe on Si(111)(7 × 7) has been studied by scanning tunneling microscopy as a function of the deposited thickness using both solid phase epitaxy and reactive deposition epitaxy. At submonolayer deposition of Fe and subsequent annealing at 600°C, flat islands of silicide with hexagonal symmetry become visible above the Si(7 × 7) reconstructed surface which supplies a bond length reference scale for the alloy. The islands tend to grow at the expense of the silicon substrate, creating a large number of surface steps. Atomically resolved images of the islands show that in all cases a cubic (2 × 2) phase is formed. The interplanar (111) distance is compatible more with the FeSi (CsCl structure) than with the FeSi 2 (CaF 2 ) epitaxy. The orthorhombic β phase does not form under the present growth conditions.