An Integrated Field-Effect Electrode for Biopotential Recording

An integrated liquid-oxide-semiconductor FET structure is described. The structure is similar to a conventional n-channel depletion mode MOSFET except the gate metal is omitted. Immersing the device in a saline solution, the drain current is controlled by the potential between the source and the solution. Operated as an active recording electrode, the structure has several properties useful in neurological research.