High-dose carbon implantations into silicon: fundamental studies for new technological tricks

Depending on the implantation temperature, the implantation of carbon ions into silicon at high doses results in the formation of either amorphous SiCx or crystalline 3C-SiC precipitates. Various aspects of the precipitation behaviour observed, such as the impeded nucleation, the limited growth and the resulting sensitivity to ballistic destruction are attributed to the large interfacial energy between crystalline silicon and 3C-SiC. Periodically arranged amorphous SiCx nanoclusters, which are formed at lower temperatures, are shown to promote amorphisation by their surrounding stress field and to represent sinks for silicon self-interstitials, which can be activated by annealing at 900 degreesC. By control of the depth distribution of equally sized, oriented 3C-SiC precipitates formed at higher implantation temperatures, it is possible to establish suitable starting conditions for the formation of buried homogeneous, single-crystalline 3C-SiC layers during a post-implantation anneal. The properties of these ion-beam-synthesised SiC layers are described and attempts to combine them with insulating and metallic layers are reviewed. A survey is given of the emerging applications of ion-beam-synthesised buried SiC layers and microstructures in electronic, optical and micromechanical devices and as large-area SiC pseudosubstrates.