Improvement of the properties and electrical performance on TiCl 4-based TiN film using sequential flow chemical vapor deposition process

Abstract

Sequential flow chemical vapor deposition (SFCVD), utilizing TiCl 4/NH 3 as reactants and immediate NH 3 treatment after film deposition, is applied to produce TiN barrier films in the contact process. Secondary ion mass spectroscopy results indicate that the SFCVD TiN film can effectively block the diffusion of WF 6 into the underlying Ti layer during W deposition. NH 3 treatment immediately after film deposition causes SFCVD TiN films to be less contaminated with carbon than TiN films that are formed by metallic organic compounds chemical vapor deposition (MOCVD) and to contain less chlorine residue than conventional TiCl 4/NH 3 CVD TiN layers even at a low reaction temperature. According to the resistance measurement of Kelvin contacts, the SFCVD process yields a lower resistance and a more uniform distribution than the MOCVD or CVD process. Transmission electron microscopic observations demonstrate that WF 6 can diffuse through the MOCVD TiN to react with the underlying Ti layer, causing a rupture at the Ti/TiN interface and poor W adhesion. The SFCVD TiN can serve as a sufficient diffusion barrier against WF 6 penetration during W CVD deposition.