Fabrication and Evaluation of Ternary Co-Fe-Si Structures Produced by Ion Beam Synthesis

Abstract

ABSTRACTDual implantation of cobalt and iron into silicon (100) wafers and subsequent annealing has been used to form layers containing mixtures of CoSi2 and FeSi2. The structure and properties of the layers were followed by Secondary Ion Mass Spectrometry (SIMS), cross-sectional transmission electron microscopy (XTEM), Transmission Electron Diffraction (TED), Rutherford Backscattering Spectroscopy (RBS), and photoluminescence (PL). When a high dose of both species was implanted, segregation of the cobalt and iron occurred which for 1000°C anneals, resulted in an epitaxial layer of αFeSi2 upon a CoSi2 layer. The epitaxial quality of both of these layers was superior to those previously fabricated by single species implants. For a low dose cobalt implant followed by a high dose iron implant, a single phase solid solution was formed and segregation did not occur. Photoluminescence at 1.54 urn was observed from this layer, but with a much lower intensity and a broader line width than that from a pure βFeSi2 layer.