Interface structure and Schottky barrier height of buried CoSi2/Si(001) layers

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Abstract
The atomic interface structure of implanted buried layers in (100) oriented Si substrates has been characterized by quantitative high‐resolution transmission electron microscopy on cross‐section specimens. The buried layers were produced by high‐dose Co+ ion implantation [100 and 200 keV Co+ ions, (1–2)×1017 cm−2] at 350 °C and subsequent rapid thermal annealing at 750 and at 1150 °C. Planar interface regions of high perfection with domains of different atomic interface structures, and interface steps, frequently with {111} facets, were observed. Comparison with computer‐simulated images for various interface models yields evidence for interface regions with six‐fold and eight‐fold coordination of the Co interface atoms. Furthermore, regions with interfaces showing a continuous transition as well as Co‐rich interfaces were found. Measurements of the Schottky barrier heights have been performed and show smaller values for the upper CoSi2/n‐Si(001) interfaces than for the lower ones. Possible correlations between the interface structures and the resulting electronic properties are discussed.