Tantalum oxide films were deposited by ECR plasma chemical vapor deposition with $Ta(OC_2H_2)_5$ and $O_2$ gas. The variables of the deposition were the deposition temperature, the microwave power and the input gas ratio. The thickness and the refractive index of the deposited films were measured by ellipsometer. The composition and structure of the deposited films were analyzed using XRD, AES and FTIR. The leakage current and breakdown voltage measurements were carried out with films of thickness about 180Å.
Throughout the experiments, the deposition rates and the refractive indices were between 5~20Å/min and 2.05~2.15, respectively. The deposition rate decreased with the deposition temperature up to 250℃ and then steadied. Also the increase of microwave power decreased the deposition rate. Higher refractive index was achieved with higher deposition temperature and microwave power, which indicates denser film structure. The change of the input gas ratio showed that $O_2$ is essential to the formation of the stable films.
The increase of deposition temperature and microwave power improved the leakage current and the breakdown voltage properties. The leakage current density (at 1 MV/cm) and breakdown field strength (at $10^{-6}$ A/㎠) were 8×$10^{-9}$ A/㎠ and 3 MV/cm respectively at 300℃ and 400 W.
