Kinetics of TiN Chemical Vapor Deposition Process using TiCl4 and NH3 for ULSI Diffusion Barrier Applications: Relationship between Step Coverage and NH3 Partial Pressure

概要

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TiN films were deposited by chemical vapor deposition (CVD) using NH3 and TiCl4 as the source precursors. The effect of partial pressures of TiCl4 ($P_{\text{TiCl$_{4}$}}$) and NH3 ($P_{\text{NH$_{3}$}}$) on the growth rate and step coverage quality of these TiN films was measured, revealing the growth rate of TiN films followed the Langmuir–Hinshelwood (L–H) type isotherm as a function of $P_{\text{TiCl$_{4}$}}$. The sticking probability of film-forming species was estimated from the step coverage profile simulated by using the Monte Carlo method. The relationship between the sticking probability of Ti-containing species and $P_{\text{NH$_{3}$}}$ was investigated, revealing that the sticking probability in the 1st-order kinetic regime depended on $P_{\text{NH$_{3}$}}$. The effect of NH3 on the growth kinetics could be expressed by $\textit{G.R.}\times\rho_{\text{TiN}}=[k_{\text{s}}KC_{\text{TiCl$_{4}$}}/(1+KC_{\text{TiCl$_{4}$}})]\cdot(C_{\text{NH$_{3}$}})^{2}$ in the wide range of $P_{\text{TiCl$_{4}$}}$. The reason for 2nd-order reaction for $P_{\text{NH$_{3}$}}$ is not clear yet, but the rate equation suggests the complicated gas-phase and/or surface reaction chemistries to form TiN.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2004-10-15