Applications of CoSi2 to VLSI and ULSI

Abstract

ABSTRACTSilicides have found application as high conductivity, high temperature, and corrosion resistance materials that form good electrical contacts to silicon and good low resistivity cladding on polysilicon films used as gate metal. Of various silicides investigated in past CoSi2 offers several advantages including lowest resistivity, self-aligned formation, low lattice mismatch with silicon, stability in presence of dopants and on SiO2, Si3N4, or Sioxynitrides, and reliability to process temperatures ≤900°C even when used in thicknesses as thin as 50-60 nm. Thus, CoSi2 has found an application in VLSI and ULSI. In this paper, the properties, formation and processing, reliability, and applicability of CoSi2 will be reviewed. It will be shown that CoSi2 is only silicide that offers properties and reliability for continued use in sub-0.25 pm VLSI and ULSI integrated circuits.