FUGITIVE DIFFUSION BARRIER FOR INTEGRATION OF SOL-GEL-DERIVED LEAD TITANATE WITH OXIDIZED SILICON SUBSTRATES

The crystalline phase development and microstructural changes with hea ting of sol-gel-derived lead titanate (PT) particles and films on sili ca with and without a fugitive (or removable) diffusion barrier layer were investigated. Amorphous gel-derived PT particles were deposited o n SiO2-coated TEM grids with and without polyimide (PI) or carbon barr ier layers between SiO2 and PT. TEM analysis showed that PI or carbon barriers prevented reaction between the gel derived PT particles and S iO2. PT particles crystallize and then the PI or carbon film decompose s. Sol-gel-derived PT films were deposited on oxidized Si substrates ( Si/SiO2) with and without a PI barrier layer. Perovskite PT films were prepared on Si/SiO2 substrates with a PI barrier; however, some poros ity remained in the films. Identically prepared films without the PI b arrier formed a mixture of pyrochlore and perovskite. X-ray photoelect ron spectroscopy results indicate that the PI film prevents the diffus ion of Si into the PT film.