Tantalum pentoxide films were reactively sputter deposited from a tantalum target using sputtering gas mixtures and annealed to form crystalline beta films. The postannealed (1000°C) films were characterized to evaluate the effects of deposition parameters and postdeposition processing on selected physical and electrical properties. Variations in the microstructure, increasing dielectric constant, and increasing dc leakage were observed as a function of film thickness between 5 and 40 nm. RF‐sputtered films exhibited micropores not observed with dc‐sputtered films. Both RF‐ and dc‐sputtered films exhibited microcracks whose density increased with film thickness. Samples having the greatest number of defects exhibited the highest dc leakage (10 nA/cm2 at 1 MV/cm), which suggests that these defects provide dc leakage paths. The measured dielectric constants varied from 10.4 to 38.9 within the film thickness range of 10–40 nm.