Improvements of trench capacitor characteristics by pre-oxidation surface cleaning with HNO/sub 3/-HF-H/sub 2/O solution

Author

Ohsawa, A. ; Takizawa, R. ; Honda, K. ; Matsutani, T. ; Imaoka, K.

Author_Institution

Fujitsu Lab. Ltd., Nakahara-ku, Kawasaki, Japan

fYear

1988

fDate

11-14 Dec. 1988

Firstpage

726

Lastpage

729

Abstract

A method has been developed for cleaning silicon by slightly etching the surfaces using an HNO/sub 3/-HF-H/sub 2/O solution with an extremely low HF concentration. The method removes near-surface damage and reduces the concentration of heavy metal surface impurities to one tenth that of RCA cleaning. The slight etch method is used for preoxidation cleaning of silicon trenches formed by reactive ion etching. The MOS C-t retention time and the defect density of thermal SiO/sub 2/ in trench capacitors are significantly improved by the cleaning. The method is effective for both trench cleaning and preoxidation cleaning.<>

Keywords

capacitors; elemental semiconductors; oxidation; semiconductor technology; silicon; sputter etching; HNO/sub 3/-HF-H/sub 2/O solution; MOS C-t retention time; RCA cleaning; RIE damage removal; Si etching; Si-SiO/sub 2/ trench capacitors; damage free surface; defect density; heavy metal surface impurities; low HF concentration; pre-oxidation surface cleaning; preoxidation cleaning; reactive ion etching; removes near-surface damage; semiconductors; slight etch method; slightly etching; thermal SiO/sub 2/; trench capacitor characteristics; trench capacitors; trench cleaning; ultraclean surfaces; wet etch; Capacitors; Etching; Hafnium; Impurities; Iron; Pollution measurement; Silicon; Surface cleaning; Testing; Very large scale integration;

fLanguage

English

Publisher

ieee

Conference_Titel

Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International

Conference_Location

San Francisco, CA, USA

ISSN

0163-1918

Type

conf

DOI

10.1109/IEDM.1988.32915

Filename

32915