A SELECTIVE CVD TUNGSTEN-STRAPPED POLYSILICON LOCAL INTERCONNECTION TECHNOLOGY

A local interconnection technology utilizing polysilicon strapped with selective CVD tungsten has been developed. Both n- and p-channel MOS transistors have been successfully fabricated using this technology. T ungsten deposited on polysilicon is an attractive gate shunt and local interconnection material because of its low resistivity, immunity to dopant segregation and diffusion, and resistance to electromigration. A potential problem of this technology is the excessive diode leakage current associated with strapping shallow source/drain diodes with tun gsten. The leakage is attributed to defects induced by the heavy sourc e/drain implant, which can be effectively eliminated with a proper ann ealing procedure.