Properties of LPCVD titanium nitride for ULSI metallization

Abstract

Summary form only given. A report is presented on a low-temperature CVD process (TiCl/sub 4/+NH/sub 3/) for deposition of conformal films, as an alternative to sputtering. Studies have been carried out at pressures of 100-300 mtorr and temperatures of 450-700 degrees C on silicon wafers with a NH/sub 3//TiCl/sub 4/ ratio of 20:1. Deposition rates as high as 1000 AA/min have been observed. Film resistivities as low as 80- Omega -cm have been seen for the thinnest films ( approximately 500 AA). The resistivity increases as the films grow thicker, apparently due to a decrease in their density. The films contain small amounts of chlorine (<4%), oxygen (<6%), and hydrogen (<11%), and have Ti/N ratios close to one. They are crystalline with columnar crystals and are adherent. Contact resistance measurements on p/sup +/ contacts annealed at 500 degrees C gave values of 2-3*10/sup -6/ Omega -cm/sup 2/. Multicontact diodes, under the same conditions, showed less than 1- mu A leakage at 10-V reverse bias.<>