Synthesis and characterization of low pressure chemically vapor deposited titanium nitride films using TiCl4 and NH3

N. Ramanuja, R. A. Levy, S. N. Dharmadhikari, E. Ramos, C. W. Pearce, S. C. Menasian, P. C. Schamberger, C. C. Collins

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

This study investigates the inter-relationships governing the growth kinetics, composition, and properties of titanium nitride (TiN) films synthesized by low pressure chemical vapor deposition (LPCVD) using titanium tetrachloride (TiCl4) and ammonia (NH3) as reactants. In the deposition temperature regime of 450 to 600 °C, an Arrhenius dependence was observed from which an activation energy of 42 kJ/mol was calculated. The growth rate dependencies on the partial pressures of NH3 (50 to 100 mTorr) and TiCl4 (1 to 12 mTorr) yielded reaction rate orders of 1.37 and -0.42, respectively. RBS spectrometry was used for establishing the Ti/N ratio and the chlorine content of the films as a function of the processing variables. Films with compositions trending towards stoichiometry were produced as the deposition temperature was decreased and the NH3 partial pressure was increased. The chlorine concentration in the films was observed to decrease from 7.2% (a/o) at the deposition temperature of 450 °C down to 0.15% at 850 °C. The film density values increased from 3.53 to 5.02 g/cm3 as the deposition temperature was increased from 550 to 850 °C. The resistivity of the films was dependent on changes in deposition temperature and flow rate ratios. The lowest resistivity value of 86 μΩ cm was measured for a deposition temperature of 600 °C and an NH3/TiCl4 flow ratio of 10/1. The film stress was found to be tensile for all deposits and to decrease with higher deposition temperatures. Nano-indentation measurements yielded values for the hardness and Young's modulus of the films to be around 15 and 250 GPa, respectively. X-ray diffraction measurements revealed in all cases the presence of cubic TiN phase with a preferred (200) orientation. For the investigated aspect ratios of up to 4:1, the deposits were observed to exhibit conformal step coverage over the investigated range of processing conditions.

Original languageEnglish (US)
Pages (from-to)261-269
Number of pages9
JournalMaterials Letters
Volume57
Issue number2
DOIs
StatePublished - Dec 2002

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Keywords

  • NH
  • TiCl
  • Titanium nitride films

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