A CVD Method of forming gate dielectric thin films on a substrate using metalloamide compounds of the formula M(NR1R2)x, or
wherein M is Zr, Hf, Y, La, Lanthanide series elements, Ta, Ti, or Al; N is nitrogen; each of R1 and R2 is same or different and is independently selected from H, aryl, perfluoroaryl, C1-C8 alkyl, C1-C8 perfluoroalkyl, alkylsilyl; and x is the oxidation state on metal M; and an aminosilane compound of the formula HxSiAy(NR1R2)4-x-y or
wherein H is hydrogen; x is from 0 to 3; Si is silicon; A is a halogen; Y is from 0 to 3; N is nitrogen; each of R1 and R2 is same or different and is independently selected from the group consisting of H, aryl, perfluoroaryl, C1-C8 alkyl, and C1-C8 perfluoroalkyl; and n is from 1-6. By comparison with the standard SiO2 gate dielectric materials, these gate dielectric materials provide low levels of carbon and halide impurity.