Chemical vapor deposition (CVD) precursor compositions for forming metal oxide high dielectric constant (κ) thin films. The precursor composition in one embodiment comprises a metal precursor having a general formula M(β-diketonate)2(OR)2, wherein M is Hf, Zr or Ti, and R is t-butyl. The precursor composition may also comprise a solvent medium selected from the group consisting of ethers, glymes, tetraglymes, amines, polyamines, alcohols, glycols, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, cyclic ethers, and compatible combinations of two or more of the foregoing.