MOCVD of Titanium Nitride from a New Precursor Ti[N(CH3)C2H5]4

Abstract

A new TiN precursor, tetrakis(ethylmethylamido)titanium (TEMAT), has been developed and characterized in terms of volatility and stability under CVD process conditions. In addition, titanium nitride thin films were prepared by means of metal organic chemical vapor deposition (MOCVD) technique, using TEMAT as a precursor. Depositions on SiO2 patterned wafers were carried out at 250-350 degrees C and the pressure of 1 Torr, yielding growth rates from 50 to 1550 Angstrom/min. Excellent bottom coverage of similar to 90% over 0.35 mu m contacts with an aspect ratio of 2.9 was achieved at 300 degrees C. This excellent bottom coverage could be explained by the fact that the TiN deposition was surface reaction controlled with an activation energy of similar to 1.0 eV. AES analysis revealed the low carbon level (similar to 18 at. %) in TEMAT-sourced TiN films, which was similar to 2x lower than that in TiN films prepared from tetrakis(diethylamido)titanium (TDEAT). We proposed the possible reaction mechanism responsible for the low carbon contents in the films, based on the byproduct gases detected by quadrupole mass spectrometer(QMS). TEMAT also produced better crystalline and less air-reactive films than tetrakis(dimethylamido)titanium (TDMAT). Consequently, the TEMAT compound can be a promisint precursor for MOCVD TiN.