Leakage current reduction in chemical-vapor-deposited Ta2O5 films by rapid thermal annealing in N2O

Abstract

This study aims to improve the electrical characteristics and reliability of low-pressure chemical vapor deposited (LPCVD) Ta2O5 films by developing a new postdeposition single-step annealing technique. Experimental results indicate that excited oxygen atoms generated by N2O decomposition can effectively repair the oxygen vacancies in the as-deposited CVD Ta2O5 film, thereby resulting in a remarkable reduction of the film's leakage current. Two other post-deposition annealing conditions are compared: rapid thermal O-2 annealing and furnace dry-O-2 annealing. The comparison reveals that RTN(2)O annealing has the lowest leakage current, superior thermal stability of electrical characteristics and the best time-dependent dielectric breakdown (TDDB) reliability.