Thermodynamics and kinetics of initial gas phase reactions in chemical vapor deposition of titanium nitride. Theoretical study of TiCl₄ ammonolysis

Abstract

Thermodynamic equilibrium and kinetics of the gas-phase reaction between TiCl 4 and NH 3 have been studied computationally using results from recent quantum mechanical calculations of titanium tetrachloride ammonolysis.1 These calculations were based upon the transition state theory for the direct reactions and RRKM theory for the reactions proceeding via intermediate complex. Rate constants for the barrierless reactions were expressed through the thermodynamic characteristics of the reagents and products using a semiempirical variational method. The kinetic simulation of the gas-phase steps of CVD was performed within a model of a well-stirred reactor at temperatures 300-1200 K and residence times between 0.1-2 s. At temperatures below 450 K formation of donor-acceptor complexes between TiCl 4 and NH 3 is the dominating process. At higher temperatures sequential direct ammonolysis takes place. At typical LPCVD conditions the only product of the first step of ammonolysis, TiCl 3 NH 2 , is formed in substantial amount.

Vinyltrimethylsilane (VTMS) as a Probe of Chemical Reactivity of a TiCN Diffusion Barrier-Covered Silicon Surface

“…In the vast majority of devices, copper is separated from a semiconductor surface by a diffusion barrier material. One of the most prominent materials, possessing high thermal stability, good diffusion barrier properties, and low electrical resistivity is titanium nitride, TiN. − This material can be deposited on a semiconductor substrate using such chemical vapor deposition precursors as dialkyl-amino derivatives (Ti[NR 2 ] 4 , where R = Me, Et) − and TiCl 4 ,− used in combination with NH 3 and sometimes H 2 ; however, the latter method often presents significant problems associated with chlorine contamination and formation of NH 4 Cl. The chemical and physical properties of TiN films can be controlled by manipulating the carbon content, and in fact, titanium carbonitride films, TiC x N y , have been shown to have a set of very attractive physical properties, including better conformal filling than titanium nitride. − …”

CHIMERA: A software tool for reaction rate calculations and kinetics and thermodynamics analysis

“…is constructed, where B is the Hermitian matrix constructed from the matrix J: (26) and c i 0 ϭ ͌ f i is the zero-order eigenvector of the matrix B. Correspondingly, the zero-order approximation 0 (0) to the lowest eigenvalue 0 is as follows: (27) This approximation to 0 is the starting point for the iterative procedure, for example…”

“…This example is based on our recent publication 26 where the thermodynamic equilibrium and kinetics of the gas-phase reaction between TiCl 4 and NH 3 were studied computationally using the recent quantum chemical calculations of titanium tetrachloride ammonolysis. 27 Titanium nitride has a unique combination of useful properties (high hardness and melting point, good electric and thermal conductivity, chemical inertness, and excellent adherence to most metals, semiconductors, and insulators) and numerous existing and potential industrial applications.…”

“…26 Because TiN CVD for microelectronic applications is typically performed at low pressures (LPCVD) with reactants diluted in a career gas, we approximated such conditions by computing a thermodynamic equilibrium and kinetics at 10 Torr pressure with the nitrogen as a carrier gas.…”

Chemical vapor deposition of titanium nitride thin films: kinetics and experiments

“…To calculate texture coefficient Tc, main diffraction peaks are taken into account: (111), (200), (220) and (420). Continued.For the traditional TiCl4-NH3 system, Umanskii et al[27] studied the reaction pathways involving complex formation (TiClxNHy). It was concluded that, in typical CVD conditions, only TiCl4NH3 is formed in substantial amount at low temperature.…”