Metalorganic chemical vapor deposition of tantalum nitride by tertbutylimidotris(diethylamido)tantalum for advanced metallization

Abstract

We deposited tantalum nitride (TaN) films by low‐pressure metalorganic chemical vapor deposition (LP‐MOCVD) using a new precursor tertbutylimidotris(diethylamido)tantalum (TBTDET). Strong Ta–N double bond in the precursor preserved the ‘‘TaN’’ portion during the pyrolysis process. This method has yielded low‐resistivity films. It changed from 10 mΩ cm (deposited at 500 °C) to 920 μΩ cm (obtained at 650 °C). The carbon and oxygen concentrations were low in the films deposited at 600 °C, as determined by x‐ray photoelectron spectroscopy.Transmission electron microscopy and x‐ray diffraction analysis indicated that the as‐deposited films exhibited polycrystalline structures with the lattice constants close to the bulk TaN value. The TaN barrier layer was successfully applied as a glue layer for CVD tungsten (W) metallization schemes.