Grain boundary plays an important role in determining the physical properties and chemical stability of the materials. In particular, the structures of grain boundaries in atomic layer deposited TiN film may be one of the main factors to dominate the reliability and performance of ULSI devices with multi-layer structure of Cu-based interconnects. The characteristics of grain boundaries in the atomic layer deposited (ALD) ultra-thin TiN films were investigated in detail here. The results showed that the small angle boundaries frequently appear in (200) epitaxy growth areas while the large angle grain boundaries were often observed in the areas with (111) close-packed stacking configuration. The tilt and twist boundaries were the two main structures of large angle grain boundaries. It was of interest to note that some large angle grain boundaries in the ALD TiN film were in an atomic scale. Such small and large angle boundaries in atomic scale lead to the pinhole free, high density and homogeneity ultra-thin polycrystalline ALD TiN film.

Grain Boundary Structures of Atomic Layer Deposited TiN. S.Li, C.Q.Sun, H.S.Park: Thin Solid Films, 2006, 504[1-2], 108-12