Thin film sol-gel derived glass

Abstract

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 photosensitizer 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.  
     
     
         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 —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.  
     
     
         15 . A method for forming a photosensitive sol-gel film including regions of different indices of refraction, said method comprising the steps of forming a photosensitive sol-gel film including an organometallic photosensitizer on a silica substrate, exposing said film through a mask to light of a wavelength and for a time for unbinding different amounts of metal constituents and of said sensitizer in different sections along at least a first channel thereof, exposing said film to heat at a first temperature and for a time to drive off the unbound sensitizer and to bind the metal constituents of said sol-gel film, and exposing said layer to heat at a second temperature higher than said first temperature for a time to unbind and drive off the organic constituents of said sol-gel film.