Atomic layer chemical vapor deposition (ALCVD) of hafnium silicate films using a precursor combination of tetrakis (diethylamido) hafnium, , and tetra--butyl orthosilicate, was studied for high-dielectric gate oxides. The ALCVD temperature window in our study was 290-350°C with a growth rate of 1.1 Å/cycle. We investigated the effect of deposition conditions, such as deposition temperature, pulse time of precursor, and purge injection, on the film growth. The saturated composition of the Hf/ ratio was 0.37, and the impurity concentrations were less than 1 atom %. The dielectric constant of the as-deposited hafnium silicate film increased upon annealing at 600°C, but decreased for annealing above 800°C. Hysteresis in the capacitance-voltage measurements was less than 0.3 V before and after annealing. The leakage current density of the as-deposited, 600°C, and 800°C annealed films was , , and , respectively, at a bias of −1 V.