FORMATION OF ULTRA-THIN BURIED COSI2 LAYERS BY ION-IMPLANTATION IN (100) SI

The formation of ultra-thin buried CoSi2 layers in (100) Si by ion beam synthesis is investigated. Layers as thin as 23 nm under 19 nm of Si are obtained by systematically lowering the dose and energy of the Co implant and continuously optimizing the implant conditions. The most critical parameter is found to be the temperature during implant. The disintegration of the CoSi2 layers upon high temperature treatment is caused by the presence of small pin-holes. The pin-hole density seems to be directly dependent on the implant conditions whereas their size is mainly determined by the subsequent high temperature treatment.