Two-step annealing technique for leakage current reduction in chemical-vapor-deposited Ta/sub 2/O/sub 5/ film

Author

Shinriki, Hiroshi ; Nakata, Masayuki ; Nishioka, Yasushiro ; Mukai, Kiichiro

Author_Institution

Hitachi Ltd., Kokubunji, Tokyo, Japan

Volume

10

Issue

11

fYear

1989

Firstpage

514

Lastpage

516

Abstract

A capacitor technology developed to obtain extremely thin Ta/sub 2/O/sub 5/ dielectric film with an effective SiO/sub 2/ film thickness down to 3 nm (equivalent to 11 fF/ mu m/sup 2/) for a 1.5-V, low-power, high-density, 64-Mb DRAM is discussed. The Ta/sub 2/O/sub 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/sub 3/) annealing with ultraviolet light irradiation, which reduces the leakage current. The second step is dry oxygen (O/sub 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.<>

Keywords

CVD coatings; annealing; dielectric thin films; leakage currents; random-access storage; semiconductor-insulator boundaries; tantalum compounds; 64 Mbit; CVD; DRAM; O/sub 2/ annealing; O/sub 3/ annealing; Ta/sub 2/O/sub 5/-SiO/sub 2/; capacitor technology; defect density; dielectric film; leakage current reduction; step coverage; thermal chemical vapor deposition; two-step annealing; ultraviolet light irradiation; Annealing; Capacitors; Chemical technology; Chemical vapor deposition; Dielectric thin films; Furnaces; Leakage current; Optical films; Semiconductor films; Silicon;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.43121

Filename

43121