Electrolytic charge inversion at programmable CMOS sensor interfaces

Electrochemical interface layer overcharging is experimentally demonstrated at planar MOS sensor interfaces by controlling the surface charge through nonvolatile charge injection. The electric field across the solid-fluid interface is modulated upon floating-gate program/erase and leads to electrolytic charge reversal, for which an analytical model is derived. This electrofluidic gating effect is further used to repel adsorbed DNA, realizing an electrical surface refreshable biosensor. Quasi-static and impedimetric measurements are presented for validation.