Atomic Layer Deposition of Tantalum Nitride Using A Novel Precursor

作者：Somani Shikha; Mukhopadhyay Atashi; Musgrave Charles^*

来源：Journal of Physical Chemistry C, 2011, 115(23): 11507-11513.

DOI：10.1021/jp1059374

We use B3LYP hybrid density functional theory to investigate atomistic mechanisms for the atomic layer deposition (ALD) of tantalum nitride (TaN) grown using tert-butylimidotris(diethylamido)tantalum [((t)BuN)-(NEt(2))(3)Ta, TBTDET], and ammonia (NH(3)) as precursors. Our calculations examine various possible mechanisms for TaN growth by ALD and metal organic chemical vapor deposition (MOCVD). In particular, we identify low barrier (10.6 and 27.6 kcal/mol) ligand exchange mechanisms with NH(3) that lead to incorporation of NH(3)'s nitrogen into the film. Ligand exchange with NH(3) is thermodynamically and kinetically favored over competing mechanisms that incorporate nitrogen from the metal precursor including: beta-hydrogen elimination of isobutene or ethene; and NH(3) catalyzed beta-hydrogen elimination of isobutene or ethene. beta-hydrogen elimination of isobutene or ethene is found to proceed through a barrier of 76.0 kcal/mol. However, our results indicate that ammonia or diethylamine produced by precursor reaction with surface amine groups can also catalyze beta-hydrogen elimination of isobutene with a predicted barrier of 64.3 kcal/mol, thus making MOCVD reactions kinetically active above similar to 600 degrees C. In addition to providing a fundamental understanding of the chemistry of TaN ALD from ((t)BuN)(NEt(2))(3)Ta and NH(3), the set of mechanisms analyzed provide new insights into the principles governing the ALD processes of other metal nitride films using imido or amido ligand transition metal complexes and ammonia as precursors.

• 出版日期2011-6-16