Wt. Sun et al., IMPROVING GATE OXIDE INTEGRITY OF COBALT SILICIDED P-TYPE POLYSILICONGATE USING ARSENIC IMPLANTATION, JPN J A P 2, 36(2A), 1997, pp. 89-92
The gate oxide integrity degradation due to the thermal instability of
cobalt silicide (CoSi2) in p-type polysilicon gate metal-oxide-semico
nductor (MOS) capacitors is alleviated by arsenic implantation into p-
type poly-Si gate. The thin gate oxides of p(+)-poly MOSFETs were seve
rely degraded due to agglomeration of cobalt silicide at high temperat
ure after silicidation. The degradation of thin: gate oxide was found
to be suppressed by the implantion of arsenic into p-type polysilicon
gate. This is due to the fact that arsenic atoms segregate simultaneou
sly into grain boundary and interface, and diffusion of decomposed cob
alt along grain boundary was then retarded during agglomeration.