Folded Floating Gate CMOS Biosensor.

A CMOS biosensor with a folded floating-gate is created for the detection of charged biochemical molecules. It is made up of a field-effect transistor with a floating-gate, a control-gate, and a sensing area. The molecules on the sensing area result in a voltage being induced on the floating-gate and a shift in the threshold characteristics. The floating-gate spans the entire device, which allows for the sensing area to be placed above the FET. This reduces the total device area. The device displays good sensitivity to the polarity and concentration of charged poly amino acids. It could be used in electronic detection of spatial and temporal charge migration in biological processes.