High-Rate Oblique Deposition of SiO2 Films Using Two Sputtering Sources

Yoichi HOSHI  Kensuke YAGI  Eisuke SUZUKI  Hao LEI  Akira SAKAI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E91-C   No.10   pp.1644-1648
Publication Date: 2008/10/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e91-c.10.1644
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Functional Thin Films for Optical Applications)
Category: 
Keyword: 
oblique deposition,  SiO2 film,  reactive sputtering,  high-rate deposition,  alignment layer,  

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Summary: 
In this paper, we proposed a new high-rate oblique deposition method using two sputtering sources to obtain SiO2 films for a liquid crystal alignment layer. One sputtering source that operates in a metal mode supplies Si atoms to a substrate, and the other source that operates in an oxide mode supplies oxygen radicals to a substrate. To reduce the gas pressure of a deposition chamber and make the two sputtering sources operate in different modes, the sputtering sources were separated from the deposition chamber with stainless meshes, and Ar and oxygen gases were introduced separately through the two sputtering sources, i.e., Ar gas was introduced through the Si supply source and oxygen gas was introduced through the oxygen radical source. When Ar gas of 30 sccm and oxygen gas of 4 sccm were introduced into the system, the gas pressure of the deposition chamber was maintained below 1.7 mTorr and the films deposited at an incidence angle of more than 70 showed an elongated inclined columnar structure. Under this condition, a deposition rate of 30 nm/min was realized even at an incidence angle above 70, where most of the Si atoms incident to the substrate were supplied by the Si supply source and the oxygen radical source supplied oxygen radicals and promoted the oxidation of the film.