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Proceedings Paper

Surface cleaning effects on reliability for devices with ultrathin oxides or oxynitrides
Author(s): Kafai Lai; Ming-Yin Hao; Wei-Ming Chen; Jack C. Lee
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Paper Abstract

A new wafer cleaning procedure has been developed for ultra-thin thermal oxidation process (<EQ 50 angstrom). This involves a modified RCA clean and a two-step dip, first in diluted HF and then in a methanol/HF solution, with no final DI water rinse. Ultrathin thermal oxides (48 angstrom) and oxynitrides grown in N2O (42 angstrom) were prepared using this new cleaning and other commonly used cleaning methods to investigate the effects of surface preparation on dielectric integrity. It has been found that this two-dip method produces dielectrics with reduced leakage current and stress-induced leakage current, which are believed to be the critical parameters for ultrathin oxides. Furthermore, this new cleaning procedure improves both intrinsic and defect-related breakdown as well as the uniformity of the current- voltage characteristics across a 4-inch wafer. The methanol/HF dip time has also been optimized. The improvement is believed to be due to enhanced silicon surface passivation by hydrogen, the reduced surface micro-roughness and the absence of native oxide.

Paper Details

Date Published: 14 September 1994
PDF: 7 pages
Proc. SPIE 2334, Microelectronics Manufacturability, Yield, and Reliability, (14 September 1994); doi: 10.1117/12.186742
Show Author Affiliations
Kafai Lai, Univ. of Texas/Austin (United States)
Ming-Yin Hao, Univ. of Texas/Austin (United States)
Wei-Ming Chen, Univ. of Texas/Austin (United States)
Jack C. Lee, Univ. of Texas/Austin (United States)

Published in SPIE Proceedings Vol. 2334:
Microelectronics Manufacturability, Yield, and Reliability
Barbara Vasquez; Hisao Kawasaki, Editor(s)

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