Nucleation of single-crystal CoSi2 with oxide-mediated epitaxy

Oxide-mediated epitaxy (OME) has shown promise as a technique for the formation of epitaxial CoSi2 on a variety of Si surfaces. With our in situ ultra-high-vacuum transmission electron microscope we have studied the phase formation sequence of the deposited Co during an anneal on both clean and oxide (OME) -covered Si (001) samples. The striking difference in OME is the absence of polycrystalline CoSi2 nucleation. We discuss the origin and consequences of this observation, and report other details of the phase evolution sequence. (C) 1999 American Institute of Physics. [S0003-6951(99)01347-9].