Sensitivity Enhancement of Electrolyte–Insulator–Semiconductor Sensors Using Mesotextured and Nanotextured Dielectric Surfaces

We report the fabrication of an electrolyte- insulator-semiconductor (EIS) device with an improved sensitivity brought about by texturization of the functionalized dielectric at the dielectric/electrolyte interface by electrostatic attachment of nanoparticle and mesoparticle. Improvement in sensitivities up to 42% over the nontextured (control) devices was obtained with SiO₂ particles on SiO₂ dielectric. The sensitivity was a function of the size of the particles with higher sensitivities being obtained with smaller particle sizes. The possible contributions of the chemical modification of the dielectric surface by the aminosilanes resulting in the modification of the surface charge, and of the physical modifications by particle texturization leading likely to enhancement of the surface densities of the active binding sites, were highlighted. A novel design for the EIS reservoir for possible improved circuit integration and manufacturability, involving a two-step reservoir in photoresist was demonstrated. This device was capable of characterizing sample volumes as small as 20 μL. A 2×1 and a 2×2 array was also demonstrated, which could be utilized for multianalyte detection.