Device-To-Circuit Integrated Design of DMFET Biosensor and Its Readout Using CMOS Pre-charge Amplifier

Dielectric Modulated Field Effect Transistor (DMFETs) offer advantages over many other well-known biosensors, making them extremely important in the fields of medicines and diagnostics. The paper aims to model a DMFET using the SPICE Level-3 model. This adapted model of the DMFET sensor can be used to detect the presence of both the charged as well as uncharged biomolecules in the nanogap cavity etched in gate-dielectric. The presence of both negatively charged and uncharged DNA molecules at the nanogap cavity changes the threshold voltage, thereby changing the on-current. Finally, this work integrates a low noise, low power pre-charge amplifier designed in 90-nm CMOS technology with the small-signal output of the adapted DMFET model. Charge sensitivity of 984.2 mV/pC was achieved without using any high magnitude passive feedback resistance.