The effect of deposition temperature on the properties of TiN diffusion barriers prepared by atomic layer chemical vapor deposition

TiN films were grown on p-type Si (100) substrates and SiO2/Si substrates by a modified atomic layer chemical vapor deposition (ALCVD) cycle using TiCl4 and NH3 as precursors. The effects of deposition temperature on growth rate, film resistivity, microstructure, and diffusion barrier properties of TiN films were investigated. The results show that the grown films are all polycrystalline with (200) preferred orientation and that the (200) texture is stronger at high deposition temperatures. The growth rate is about 0.03 nm/deposition cycle, and almost independent of deposition temperature. The resistivity, however, exponentially decreases with increasing deposition temperature. The chlorine impurity concentration measured by Auger electron spectrometry is lower than 1 at.% for films grown at deposition temperatures above 350 degrees C. Atomic force microscopy analysis reveals that the surface quality is good with root mean square roughness values below 0.9 nm. Various Cu/ALCVD TiN/Si samples were annealed at temperatures between 500 and 800 degrees C in vacuum ambient of 6.67 x 10(-4) Pa for 1 h to evaluate the performance of TiN barriers. It is found that the failure temperature of TiN barriers is related to the deposition temperature. The failure temperatures are 600, 600-650, 700, and 750 degrees C for the TiN films deposited at 300, 350-400, 450, and 500 degrees C, respectively. The formation of voids at some weak spots after annealing suggests that Cl residues are responsible for the cause of early failure of ALCVD TiN barriers. (c) 2005 Elsevier B.V. All rights reserved.