Integrated circuit for a chemical-selective sensor with voltage output

TLDR: An integrated circuit for a miniaturized solid-state chemical sensor as mentioned in this paper includes a chemical-selective membrane which provides an electric signal in response to contact with a particular chemical or group of chemicals in a fluid.

Abstract: An integrated circuit for a miniaturized solid-state chemical sensor. The integrated circuit includes a chemical-selective membrane which provides an electric signal in response to contact with a particular chemical or group of chemicals in a fluid. The chemical-selective membrane is attached to the integrated circuit by a membrane definition layer. An electrically conductive layer beneath the membrane definition layer provides electrical contact between the chemical-selective membrane and one of the input transistors of the voltage-follower amplifier. The chemical-selective membrane is formed separately from the gate of the input transistors and is designed as a integrated input to the amplifier. The output of the chemical sensor is a low impedance electric signal represented as a voltage which corresponds to the chemical activity present at the chemical-selective membrane/fluid interface. In one embodiment, multiple chemical sensors are fabricated on a single integrated circuit wherein each chemical-selective sensor forms an integrated input to a separate amplifier. Included on the integrated circuit of that embodiment is circuitry to allow for multiplexing of the outputs of the amplifiers to one or both of two output pads provided on the integrated circuit.