Design and technological characterization aspects of a gluco-detector BioFET

This paper presents the simulations results and preliminary experiments of a glucose BioFET constructed with a dielectric multi-layer Si/SiO₂/Si₃N₄/Al₂O₃. Beside to the Si/SiO₂ system, the biosensors processing involves special attention to the intermediate layer responsible for the biological receptors entrapping. A first experience imposes to use the Si₃N₄ layer over the SiO₂ layer mainly to stops the Na⁺ and K⁺ ions diffusion from the bioenvironment toward the silicon transducer. The nitride beside to a porous top Al₂O₃ layer grown by anodization, helps to a better enzyme entrapping, maintains the GOD active centres and are in agreement with the planar technology requirements. An original Al₂O₃ deposition technique is presented. The final multilayer structure was characterized as a capacitor using a CV-meter and an ellipsometer.