Low temperature deposition of TaCN films using pentakis(diethylamido)tantalum

TaCN films were deposited at low temperature (less than or equal to 400 degrees C) by metallorganic chemical vapor deposition (MOCVD) using pentakis(diethylamido)tantalum (PDEAT) as a precursor. The activation energy of the surface reaction is about 0.79 eV and the maximum deposition rate is about 100 Angstrom/min at 350 degrees C. The resistivity of the as-deposited film decreases as the deposition temperature increases and the minimum value of resistivity obtained is 6000 mu Omega-cm for the sample deposited at 400 degrees C. Major chemical elements in the films were detected as Ta, C, and N with some amounts of O by Anger electron spectroscopy (AES). By x-ray photoelectron spectroscopy (XPS), it is identified that the most of carbon in the films was bonded to Ta. The microstructural investigation using high resolution transmission electron microscopy reveals a nanocrystalline phase with an average grain size of about 30 Angstrom. Preliminary investigation of the diffusion barrier property for copper showed that the 300 Angstrom of TaCN diffusion barrier was failed after annealing at 500 degrees C for 1 hr.