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Proceedings Paper

Interface structure during silicon oxidation
Author(s): J. Murray Gibson
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Paper Abstract

The silicon dioxide/silicon interface is critical in the electrical behavior of metal-oxidesemiconductor (MOS) field-effect transistors. As device dimensions shrink, roughness at this interface becomes increasingly important to electrical properties for two reasons. Roughness-induced local thickness variations lead to more significant fluctuating electric fields, and oxide growth temperatures must be reduced for thin oxides, leading to greater roughness. In this paper several experiments are described which provide information on the degree of roughness and its origin during the oxidation process. There are two types of experiments discussed: direct observation of atomic steps and structure during the very initial stages of room-temperature oxide growth on ultraclean Si(1 1 1) surfaces, and determination of roughness at conventional furnace-grown Si/SiO2 interfaces by a novel electron diffraction technique. The results of both these studies suggest that oxidation occurs primarily by the breaking of backbonds adjacent to the interface, and not by a terrace-ledge-kink mechanism. As a result, roughness is intrinsically created by the oxidation process, and can be removed only by a post-oxidation anneal. There is also evidence that the interface tension of Si/Si02 is sufficiently high, especially on Si(1 1 1), that it drives interface flattening during non-oxidizing thermal anneals.

Paper Details

Date Published: 1 October 1990
PDF: 5 pages
Proc. SPIE 1284, Nanostructure and Microstructure Correlation with Physical Properties of Semiconductors, (1 October 1990); doi: 10.1117/12.20792
Show Author Affiliations
J. Murray Gibson, AT&T Bell Labs. (United States)

Published in SPIE Proceedings Vol. 1284:
Nanostructure and Microstructure Correlation with Physical Properties of Semiconductors
Harold G. Craighead; J. Murray Gibson, Editor(s)

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