AVS 46th International Symposium
    Manufacturing Science and Technology Group Monday Sessions
       Session MS-MoA

Invited Paper MS-MoA1
Highly Reliable Ultra Thin Gate Oxide Grown using Water Vapor Generator

Monday, October 25, 1999, 2:00 pm, Room 611

Session: Ultra-Clean Society and Contamination Free Manufacturing
Presenter: O. Nakamura, Tohoku University, Japan
Authors: O. Nakamura, Tohoku University, Japan
T. Ohkawa, Tohoku University, Japan
M. Nakagawa, Tohoku University, Japan
Y. Shirai, Tohoku University, Japan
K. Kawada, Fujikin Incorporated, Japan
N. Ikeda, Fujikin Incorporated, Japan
Y. Minami, Fujikin Incorporated, Japan
A. Morimoto, Fujikin Incorporated, Japan
T. Ohmi, Tohoku University, Japan
Correspondent: Click to Email
High-reliability ultra thin oxide film is required for future ULSI manufacturing, where perfect uniformity and very high yield in volume production of large diameter wafers era must be guaranteed. In case of wet oxidation, water vapor is most commonly generated by burning H@sub 2@ in O@sub 2@ ambient. So, this torch-type has a potential problem of particle contamination of the water due to the micro-powder from the quartz combustion nozzle. In order to obtain wet ambient without contamination, we have developed a new Water Vapor Generator (WVG) using catalytic reactor. Additionally, the WVG can generate H2O from the vacuum to the high-pressure condition. This WVG is expected to be used in various processes where water vapor is needed.In this presentation, we will demonstrate a new gate oxidation process to form high-reliability ultra thin gate oxide at low temperature with highly concentrated H@sub 2@O using WVG system. For example, for substrate injection, the 50% Q@sub BD@ values of conventional dry oxides (900@super o@C) and advanced wet oxides formed at the low temperature using highly concentrated moisture (90% H@sub 2@O/Ar, 750@super o@C) are 9.5 C/cm@super 2@ and 70 C/cm@super 2@, respectively. For gate injection, the 50% Q@sub BD@ values of conventional oxides and advanced oxides are 6.5 C/cm@super 2@ and 25 C/cm@super 2@, respectively. Moreover, we will discuss the influence of oxidation ambiences such as surplus O@sub 2@ and H@sub 2@ ambience and oxidation temperature for electrical characteristics. In conclusion, ultra thin gate oxide using WVG has high breakdown strength under electrical stress. A newly developed oxidation is effective to grow a tunnel oxide for flash memory, which is operated under high electric field.