Two-step annealing technique for leakage current reduction inchemical-vapor-deposited Ta(2)O(5) film

• Published in: IEEE electron device letters Vol. 10; no. 11; pp. 514 - 516
• Main Authors: Shinriki, H, Nakata, M, Nishioka, Y, Mukai, K
• Format: Journal Article
• Language: English
• Published: 01-11-1989
• ISSN: 0741-3106
• DOI: 10.1109/55.43121

A capacitor technology developed to obtain extremely thin Ta(2 )O(5) dielectric film with an effective SiO(2) film thickness down to 3 nm (equivalent to 11 fF/mum(2)) for a 1.5-V, low-power, high-density, 64-Mb DRAM is discussed. The Ta(2 )O(5) has low leakage current, low defect density, and excellent step coverage. The key process is two-step annealing after the deposition of the film by thermal chemical vapor deposition (CVD). The first step involves ozone (O(3)) annealing with ultraviolet light irradiation, which reduces the leakage current. The second step is dry oxygen (O(2)) annealing, which decreases the defect density. A more significant reduction in the leakage current is attained by the combination of the two annealing steps