Conformality of chemical-vapor-deposited tungsten on TiN prepared by metal-organic chemical vapor deposition via cyclic plasma treatment

The conformality of the chemical-vapor-deposited (CVD) W films is investiga ted with TIN films prepared by chemical vapor deposition using tetrakis-dim ethylamino-titanium (TDMAT). Plasma treatment of TDMAT-TiN films is shown t o he unsuccessful at removing volatile impurities from side-wall films. The conformality of CVD W films is improved with thinner TDMAT-TiN films and w ith a low contact aspect ratio. Based on the results of chemical analysis a nd annealing experiments, we deduce that outgassing from the TiN film on th e side wall of holes strongly affects the conformality of CVD W films. Vola tile impurities in the TiN film lead to slower growth of W films on the sid e-wall than on the top of the holes, which results in the deterioration of the conformality of W films.