Deep Submicron EGFET Based on Transistor Association Technique for Chemical Sensing

Area of Science:

• Electronics
• Materials Science
• Biotechnology

Background:

• Extended-gate field-effect transistors (EGFETs) are alternatives to ion-sensitive field-effect transistors (ISFETs) for biosensor applications.
• Research on EGFET electronic interfaces, including noise and scaling, is limited, hindering biosensor optimization.
• Custom EGFETs can enhance biosensor performance beyond commercial off-the-shelf components.

Purpose of the Study:

• To design and characterize a transistor association (TA)-based EGFET.
• To evaluate the performance of custom EGFETs manufactured using a 130 nm standard complementary metal-oxide semiconductor (CMOS) process.
• To compare the performance of the developed EGFETs with existing literature.

Main Methods:

• Fabrication of EGFET prototypes using a 130 nm standard CMOS process.
• Characterization of DC equivalence, power consumption, die area, and input-referred noise.
• Validation of EGFET performance as a pH sensor, measuring voltage and current sensitivity and linearity.

Main Results:

• The TA-based EGFET demonstrated DC equivalence with single-transistor counterparts.
• Power consumption was 24.99 mW at 1.2 V, with a minimum die area of 0.685 × 1.2 mm².
• Higher aspect ratio devices exhibited lower input-referred noise (minimum 176.4 nVrms) but increased die area and power consumption.
• EGFETs achieved an average voltage sensitivity of 50.3 mV/pH, high linearity (>99.9%), and operated at low noise levels.

Conclusions:

• The custom TA-based EGFET design offers a viable path for high-performance biosensors.
• The developed EGFETs provide a balance between compact design, low complexity, and reduced noise operation.
• This research contributes to the understanding and optimization of EGFETs for advanced biosensing applications.