Degradation of the Poly-Si/Silicide Structure in Advanced MOS-Technologies

The interaction in the system poly-Si on TiSi2 on Si and in the polycide system both with CoSi2 and TiSi2 is investigated when subjected to furnace heat treatments at high temperature. It will be shown that the first system suffers from instability due to SPE-regrowth which is partially avoided by doping the poly-Si. The polycide system shows severe roughening of the TiSi2. However, in the case of CoSi2, the degradation is more pronounced, viz. the Co is detected all over the poly-Si layer and this can hardly be suppressed by doping of the CoSi2-layer.