Growth kinetics and properties of LPCVD titanium nitride films synthesized using TiCl4 and NH3

The growth kinetics and properties of titanium nitride (TiN) films synthesized by low pressure chemical vapor deposition (LPCVD) using titanium tetrachloride (TiCl4), ammonia (NH3), and argon (Ar) as a carrier gas was studied. The deposition temperature was varied from 450 to 850 degrees C at a constant total pressure of 100 mTorr. An activation energy of 41.82 kJ/mor was determined for the reaction and the following rate equation was obtained: r = 4.35x10(-5)exp(-5 150/T) (P-NH3)(1.37)(P-TiCl4)(.042) The density of the film increased from 4.0 to 5.4 g/cm(3) while the film stress decreased from 430 to 177 MPa (tensile) as the deposition temperature was increased from 450 to 850 degrees C. Film resistivity ranged from 86 to 250 mu.ohm.cm, with the lowest resistivity being obtained at a temperature of 600 degrees C and NH3/TiCl4 flow ratio of 10. The film hardness was found to be independent of the deposition temperature and was around 15 GPa, while the Young's modulus increased from 80 to 350 GPa with an increase in deposition temperature. X-ray diffraction identified the phase to be cubic TiN and the lattice constant was calculated to be 4.26 Angstrom. Rutherford backscattering spectroscopy (RBS) was used determine the Ti/N stoichiometry and the chlorine content of the films. Films deposited above 600 degrees C contained <2 atomic percent (a/o) of chlorine, while those deposited at lower temperatures contained 4-7 atomic percent chlorine.