Effect of ozone annealing on the dielectric properties of tantalum oxide thin films grown by chemical vapor deposition

Effects of the heat treatment in flowing oxygen containing ozone of 0.5--1 vol % (O3 annealing) on the dielectric properties of the Ta2O5 thin film (100--200 A) grown on the Si substrate by the chemical vapor deposition method were investigated. The leakage current was drastically reduced from more than 10-3 to 10-9 A/cm2 in an electric field of 3 MV/cm by the O3 annealing at 400 degree C. It was also found that the leakage current was decreased and increased reversibly between alternate O3 annealing and O2 annealing (without ozone). These two states of the leakage current can be attributed to the reproducible change of the oxygen vacancies in the Ta2O5 film