Comparison of tetrakis(dimethylamido)titanium and tetrakis(diethylamido)titanium as precursors for metallorganic chemical vapor deposition of titanium nitride

Abstract

Tetrakis(dimethylamido)titanium (TDMAT) and tetrakis(diethylamido)titanium (TDEAT) as precursors for metallorganic chemical vapor deposition of TiN were compared. H-1 nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC) were used to study the thermal decomposition behavior of the liquid-phase compounds. NMR spectra showed that TDEAT was thermally stable up to 220 degrees C, while TDMAT began to decompose over 140 degrees C. DSC results also confirmed that TDEAT had a better thermal stability than TDMAT. The gas-phase reaction mechanism of the compounds monitored by in situ Fourier transform infrared spectroscopy and TDEAT was decomposed at higher temperature due to its steric hindrance effect. TDMAT and TDEAT had a similar dissociation mechanism in the liquid and gas phase. Both precursors were decomposed at high temperatures into Ti metal and dialkylamine. The deposition rate of TiN was higher with TDMAT than with TDEAT, and TiN films deposited with TDMAT showed lower carbon content and smooth surface morphology. (C) 1999 The Electrochemical Society. S0013-4651(98)07-050-5. All rights reserved.