RAPID THERMAL-PROCESSING RELIABILITY OF TITANIUM SILICIDE IMPLANTED WITH ARSENIC, BORON AND PHOSPHORUS

Arsenic, boron and phosphorus have been implanted into thin layers (about 40 nm) of TiSi2 prepared by metal-silicon reaction in a RTA apparatus. The change in composition and morphology of the silicide, due to the high temperature processing (900-1150-degrees-C), has been investigated by means of Rutherford backscattering spectrometry and sheet resistance measurements on Van der Pauw structures. In the arsenic implanted TiSi2 no significant improvement of the stability with respect to the unimplanted silicide was found. However, in both the boron and the phosphorus implanted films, a better reliability has been observed. This effect may be explained in terms of titanium-boride and titanium-phosphide formation at the TiSi2 grain boundaries. The silicon diffusion along the grain boundary is considerably prevented, and then the groove formation is delayed. The influence of this investigation on the formation of shallow junctions is also discussed.