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) Ta/sub 2/O/sub 5/, films by developing a new post-deposition single-step annealing technique. Experimental results indicate that excited oxygen atoms generated by N/sub 2/O decomposition can effectively repair the oxygen vacancies in the as-deposited CVD Ta/sub 2/O/sub 5/ film, thereby resulting in a remarkable reduction of the film's leakage current. Two other post-deposition annealing conditions are compared: rapid thermal O/sub 2/ annealing and furnace dry-O/sub 2/ annealing. The comparison reveals that RTN/sub 2/O annealing has the lowest leakage current, superior thermal stability of electrical characteristics and the best time-dependent dielectric breakdown (TDDB) reliability.