High performance dual-gate ISFET with non-ideal effect reduction schemes in a SOI-CMOS bioelectrical SoC

A dual-gate ion-sensitive field-effect transistor (DGFET) with the back-side sensing structure implemented in a 0.18 μm SOI-CMOS SoC platform realizing high performance bioelectrical detection with non-ideal effect reduction is presented. Non-ideal effects of the conventional ISFET, such as time drift and hysteresis, are suppressed by the innovative scheme in DGFET using the bottom poly-gate (PG) transistor instead of the fluidic gate (FG) transistor for sensing. As a result, the signal-to-noise ratio (SNR) is improved by 155x, time drift is reduced by 53x, and hysteresis is reduced by 3.7x. For certain applications which require high sensitivity, a pulse-modulated biasing technique can be adopted to effectively reduce time drift with high pH sensitivity of 453 mV/pH which is ~7.5x enhancement over the Nernst limit in the proposed DGFET.