✍ Scribed by A.-C. Salaün; F. Le Bihan; T. Mohammed-Brahim
No coin nor oath required. For personal study only.
High sensitivity to chemical species of sub-micron gap Suspended-Gate FETs (more than 200 mV/pH for example) is explained from the charge distribution induced by the high field in the sub-micronic gap under the gate-bridge. Modeling of Metal-Electrolyte-Insulator-Silicon (MEIS) capacitor, which is the basic vertical structure of the transistor, is performed to highlight this effect through the response to the pH change of the solution filling the gap. The analytical model is based on the 2D-numerical resolution of Poisson's equation. The response of quasi-static C(V) plots versus pH is simulated using both electrolyte charge distribution and site-binding theory considering the influence of sites densities on silicon nitride. Device modeling and simulated/experimental electrical characteristics are presented. Effect of the gap thickness on the pH sensitivity is also discussed in this study.
📜 SIMILAR VOLUMES
The adsorption at the open insulator surface under the air gap of suspended-gate field-effect transistors (SGFETs), which leads to mobile charges, and their r~~bution due to lateral clectrica~ field strengths are two of the reasons for the threshold voltage ins~bility of these gas sensors. A two-dim