Abnormal room-temperature oxidation of silicon in the presence of copper

• Published in: Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vol. 20; no. 5; pp. 1653 - 1658
• Main Authors: Hinode, Kenji, Takeda, Ken’ichi, Kondo, Seiichi
• Format: Journal Article
• Language: English
• Published: 01-09-2002
• Subjects: Copper; Crystal atomic structure; Electron beams; Evaporation; Image analysis; Metallizing; Morphology; Oxidation; Surface reactions; X ray diffraction analysis; Cu; Si
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/1.1497179

The room-temperature reaction between copper (Cu) and silicon (Si) was investigated. The areas of an Si substrate covered with very thin or island-like Cu oxidized formed thick (>100 nm) oxide
(
SiO
2
).
The areas covered with thick and nonisland-like Cu film did not. These unoxidized areas transformed into
SiO
2
when the side surfaces of the sample were exposed to air after sectioning for transmission electron microscope observation. The supply of oxygen was found to control this oxidation process. The presence of a Cu silicide, such as
Cu
3
Si
,
was found to not necessarily be needed for oxidation. The oxidation rate estimated from observation was about 150 nm/month. Copper atoms were detected at the
SiO
2
/Si
interface and identified not as silicides but as body-center-cubic-structured Cu several atom layers thick.