Composite TiSi2/n+ poly-Si low resistivity gate electrode and interconnect for VLSI device technology

A composite polycide structure consisting of coevaporated TiSi
2
film on top of polysilicon is studied as a replacement for polysilicon as gate electrode and interconnect line in very large scale integrated circuits. Coevaporated TiSi
2
polycide gate with sheet resistivity of 1 Ω/square (bulk resistivity of 21
\micro\Omega
-cm) was chosen for this study because of 2 times to 5 times lower resistivity as compared to other silicides. Anisotropic etching of nominally 1
\micro
m lines with a 15:1 etch selectivity against oxide is reported. The device characteristics of MOSFET's with TiSi
2
polycide gates correspond very closely to those with n+ poly-Si gates.