Comparison of Multiple-Polysilicon-Nanowire pH-Sensors Coated with Different ALD-Deposited High-k Dielectric Materials

Abstract

Multiple poly-silicon nanowires (PS-NW\'s) coated with different high-k dielectric materials, HfO2, Al2O3, and TiO2, were fabricated and their pH sensing characteristics were compared. Sidewall spacer formation technique was used for the PS-NW\'s fabrication and all the high-k materials were deposited by atomic-layer-deposition (ALD). Following the high-k dielectric deposition, a 3-aminopropyltriethoxysilane (gamma-APTES) layer was coated as sensing membrane. It is found that the multiple PS-NW sensor coated with HfO2 exhibits the highest sensitivity and best reproducibility for pH sensing.