Nuclear instruments & methods in physics research section b-beam interactions with materials and atoms vol:80-1 pages:906-909
Ion beam synthesis is a very successful technique to create buried CoSi2 layers in Si. Recently we have reported on the synthesis of CoSi2 in SiGe and on the redistribution of Ge that accompanies this formation of a buried CoSi, layer [A. Lauwers et al., Mater. Res. Soc. Symp. Proc. 235 (1992) 299]. The aim of the present work is to study the impact of increasing the SiGe lattice parameter on the growth of the buried layer. Epitaxial Si1-xGex alloy layers with different Ge concentrations are implanted with high doses of Co. The Co doses are varied between 0.6 x 10(17) and 2 x 10(17) at. /cm2. The influence of the Ge concentration on the strain situation in the as-implanted samples is studied. Increasing. the SiGe lattice parameter is found to change not only the strain but also the type and the size distribution of the CoSi2 precipitates. The formation of a buried CoSi2 layer during subsequent anneal is observed to be hindered by increasing the Ge concentration.