Thin film sol-gel derived glass
View Patent ↗Thermally-assisted organometallic sol-gel derived glasses have been found to permit fabrication of thin films sufficiently thin for telecom components. Inclusion of a photosensitizer in the film permits light of controlled intensity to modify refractive indices in the film to form useful structures.
1. A glass thin film derived from a thin film of photosensitive sol-gel doped with an organometallic photosensitizer, said organometallic photosenitizer having a formula R-M-X, where X is a photolabile moiety, M is a metal, and R is a volatile organic compound, wherein said thin film of photosensitive sol-gel has a thickness in excess of one micron, is exposed to light in at least one region to unbind X constituents from M constituents of said photosensitizer within said at least one region and to bind the resulting M constituents to the sol-gel, and is heat treated to drive off the unexposed photosensitizer and unbound X constituents and to permanently bind the M constituents to a sol-gel derived glass matrix and thereby form said glass thin film, and wherein said heat treatment is carried out in a manner that does not cause lateral shrinkage or cracking of said glass thin film.
2. A thin film as in claim 1 , said film being formed on a substrate having a surface including silicon and oxygen.
3. A thin film as in claim 2 wherein said surface comprises SiO 2 and is a silica enriched thin layer on a silicon substrate.
4. A thin film as in claim 1 , said film being formed on a glass substrate.
5. A thin film as in claim 1 , wherein R is taken from a class of low-volatile organic molecules consisting of CH 3 , CH 3 —CH 2 , CH 3 —CH 2 — and CH 2 , and Cp, M is a metal taken from a class consisting of metals in Groups IVA, IVB, and VIB, transition metals and rare earth metals, and X is a photolabile moiety taken from a class consisting of halogens and carbonyls.
6. A thin film as in claim 3 where R comprises CH 3 , M comprises Sn, and X comprises I.
7. A thin film as in claim 3 wherein R comprises cyclopentadienyl.
8. A thin film as in claim 3 wherein M comprises Ti.
9. A thin film as in claim 3 wherein X comprises Cl.
10. A thin film as in claim 4 wherein R comprises CH 3 .
11. A thin film as in claim 4 wherein M comprises Pb.
12. A thin film as in claim 4 wherein X comprises Cl.
13. A thin film as in claim 2 including thereon a mask opaque to light in the UV and visible ranges.
14. A thin film of sol-gel derived glass on a silica substrate, said film including at least one metal oxide doped silica region of Si—O—M—O—Si with adjacent regions of SiO 2 , where M is a metal, said film having a thickness substantially in excess of one micron and being free of cracks and lateral shrinkage, and wherein said metal oxide is photodeposited from an organometallic photosensitizer included in the sol-gel used to form said film.