Titanium nitride is of interest for IC fabrication because of its excellent performance as a metallic diffusion barrier. TiN films have been deposited in a batch sputtering system equipped with dc magnetron cathodes, rf substrate bias, and independently controlled Ar and N2 sources. A threshold value of N2 flow exists, above which nitridation of the Ti target face is believed to occur. Operation above this threshold results in lower deposition rate and higher cathode voltage. It is demonstrated that high quality films can be deposited at N2 flows below the target nitridation threshold, resulting in an approximate threefold improvement in deposition rate. As-deposited films on (100) silicon have resistivities of 50–60 μΩ cm and moderate compressive stress. rf substrate bias is required to achieve these resistivities; excess bias increases compressive stress. RBS profiles of deposited films show low levels of oxygen contamination and nominally stoichiometric films over a considerable range of deposition conditions. The films can be dry etched using conventional aluminum etch equipment and chemistries. The resulting etch profiles are anisotropic with no tendency to undercut. Films deposited under these conditions also have the potential of reducing particulate generation, since the deposits which accumulate on unbiased shielding within the deposition chamber are Ti, rather than the more brittle and compressively stressed TiN.
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Jim Stimmell (1986) studied this question.