Epitaxial liftoff techniques have been used in integrated circuit fabrication since 1987. This technology presents methods for detaching a micron-thin single-crystal film from an epilayer/substrate or bulk crystal structure in order to integrate metal oxides into electro-optic, magneto-optic, and microwave communication devices. This surpasses conventional methods' effectiveness at growing single crystal-structures that exhibit good optical and magnetic properties for combination with semiconductor materials.
The technology requires implanting ions into the crystal structure to form a damage layer at an implantation depth below the top surface, with subsequent chemical etching of the damage layer to effect detachment. The thin film may also be detached by rapidly heating the damage layer, without chemical etching. This thin film can then be bonded onto growth-incompatible substrates. The crystal can be of metal oxide materials and can also be made of magnetic garnet or ferroelectric materials. Thin films of lithium niobate (LiNbO3) as large as 5x5 mm have been fabricated using this method. Methods for enhancing the crystal slicing etch-rate are also described. Particularly, this method can be used to fabricate wave retarder plate for optical wave guide polarization mode converter. The depth of defective layer is predetermined by the optical retardance of the wave retarder plate and the wavelength of light for which the plate is designed.
Patent Issued (US 6,540,827)
Patent Issued (US 6,120,597)
Tech Ventures Reference: IR M00-048
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