Effect of lattice mismatch on the epitaxy of sol-gel LiNbO{sub 3} thin films
- Materials Department and Materials Research Laboratory, University of California, Santa Barbara, California 93106 (United States)
A solution precursor method based on metal alkoxides was used to produce epitaxial LiNbO{sub 3} thin films, {approx}200nm thick, on (0001) sapphire substrates. Transmission electron microscopy revealed that the major cause of surface roughness in these films was grain boundary grooves between mosaic grains with misorientations {le}5{degree}. It is postulated that these low angle boundaries directly result in surface grooving and roughness. The epitaxial films also contained two distinguishable variants in the film/substrate interfacial plane, namely, an aligned variant, {l_angle}{bar 1}2{bar 1}0{r_angle}{sub LiNbO{sub 3}}{parallel}{l_angle}{bar 1}2{bar 1}0{r_angle}{sub Al{sub 2}O{sub 3}} and 60{degree} rotated variant, {l_angle}{bar 1}2{bar 1}0{r_angle}{sub LiNbO{sub 3}}{parallel}{l_angle}1{bar 2}10{r_angle}{sub Al{sub 2}O{sub 3}}. A seeded grain growth method was used to minimize the presence of the 60{degree} rotated variant. An epitaxial buffer layer of Fe{sub 2}O{sub 3} was used to lower the mismatch strain, eliminate the 60{degree} rotated variant, and reduce the mosaic nature of the LiNbO{sub 3} film. X-ray rocking curve full-width-at-half-maximum (FWHM) values measured on the (01{bar 1}2) film peak indicate that the mosaic character can be reduced from 1.5{degree} to 0.76{degree} by using a buffer layer. {copyright} {ital 1997 Materials Research Society.}
- OSTI ID:
- 508973
- Journal Information:
- Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 5 Vol. 12; ISSN JMREEE; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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