Initial growth stage of nanoscaled TiN films: Formation of continuous amorphous layers and thickness-dependent crystal nucleation

The initial growth stage of titanium nitride (TiN) deposited by reactive magnetron dc sputtering onto (111)-oriented Si substrates was investigated by using high-resolution transmission electron microscopy (HRTEM). During the initial growth stage, a continuous amorphous layer was observed when the deposited film was less than I nm thick. Crystal nucleation occurred from the amorphous layer when the film grew to about 2 nm thick. No pref erred orientation was found for the initial crystal nuclei. The growth of the crystal grains depended on the N-2 partial pressure, P-N2. Increasing P-N2 from 0.047 to 0.47 Pa enhanced lateral grain growth and coalescence between grains. For P-N2 = 0.47 Pa, planar grains with a large lateral dimension were found formed by grain growth and coalescence; inducing a (200) film orientation. For films formed at P-N2 = 0.47 Pa, an amorphous interlayer 1.5-1.8 nm thick formed between the TiN layer and Si substrate, and was indicated to be primarily SiNx by x-ray photoelectron spectroscopy and HRTEM. This interlayer was less than 0.5 nm thick in films formed at P-N2 = 0.047 Pa. (C) 2003 American Vacuum Society.