Methods and compositions for depositing high-k films are disclosed herein. In general, the disclosed methods utilize precursor compounds comprising Ta or Nb. More specifically, the disclosed precursor compounds utilize certain ligands coupled to Ta and/or Nb such as 1-methoxy-2-methyl-2-propanolate (mmp) to increase volatility. Furthermore, methods of depositing Ta or Nb compounds are disclosed in conjunction with use of Hf and/or Zr precursors to deposit Ta-doped or Nb-doped Hf and/or Zr films, The methods and compositions may be used in CVD, ALD, or pulsed CVD deposition processes.