Provided are methods of depositing tantalum-containing films via atomic layer deposition and/or chemical vapor deposition. The method comprises exposing a substrate surface to flows of a first precursor comprising TaClxR5-x, TaBrxR5-x or TaIxR5-x, wherein R is a non-halide ligand, and a second precursor comprising an aluminum-containing compound, wherein x has a value in the range of 1 to 4. The R group may be C1-C5 alkyl, and specifically methyl. The resulting films comprise tantalum, aluminum and/or carbon. Certain other methods relate to reacting Ta2Cl10 with a coordinating ligand to provide TaCl5 coordinated to the ligand. A substrate surface may be exposed to flows of a first precursor and second precursor, the first precursor comprising the TaCl5 coordinated to a ligand, the second precursor comprising an aluminum-containing compound.