Thin Solid Films, Vol.320, No.1, 15-19, 1998
MOCVD of TiN and/or Ti from new precursors
Titanium nitride films were prepared by means of metal organic chemical vapor deposition (MOCVD) technique, using a new TiN precursor tetrakis (ethylmethyl-amido) titanium (TEMAT). Deposition of TiN films at the low temperature of 250-350 degrees C yielded growth rates of 70 to 1050 Angstrom/min with the excellent bottom coverage of similar to 90% over 0.35 mu m contacts. The addition of ammonia to a TEMAT chemistry lowered the resistivity of as-deposited TiN film to similar to 1000 mu Omega cm from 3500-6000 mu Omega cm and reduced the resistivity variation in TiN film upon air-exposure. Examination of the films by Auger electron spectroscopy (AES) showed that the oxygen and carbon contents decreased significantly with the addition of ammonia. Based on the byproduct gases detected by quadrupole mass spectrometer (QMS), the transamination reaction, similar to that of TDMAT with NH3, was proposed to be responsible for TiN deposition. Since steric interactions determines the extent of the gas phase reaction, the reactivity of TEMAT with NH, in gas phase must be less than that of TDMAT with NH,, and thus, facilitating the control of the gas phase reaction. Finally, we examined MOCVD Ti using a new compound, (acac)(2)TiNEt2 to find out the possibility of the sequential process for MOCVD TiN/Ti. No thermal decomposition of the chemistry occurred up to 380 degrees C, but the use of plasma enabled the dissociation of (acac)(2)TiNEt2, resulting in gold-colored films. However, the films mainly consisted of carbon.
Keywords:DEPOSITION