Effortless and controllable electrical amplification in single-PMOS sensor for chemical and biological sensing

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Field-effect transistors (FETs) are widely used in sensing applications.
• Enhancing the sensitivity of FET-based sensors often requires complex circuitry or specialized materials.
• Existing methods for improving FET sensitivity face limitations in cost and scalability.

Purpose of the Study:

• To introduce a novel body-coupled modulation strategy for electrical amplification of sensitivity in p-channel metal-oxide semiconductor field-effect transistors (PMOS FETs).
• To demonstrate a significant enhancement in sensor sensitivity without additional circuit or process complexity.
• To explore the potential of this strategy for ultra-sensitive electrochemical and biological sensing.

Main Methods:

• Utilized a nonlinear readout body-coupled modulation strategy by dynamically biasing the body terminal of a PMOS FET.
• Implemented the strategy on a commercial PMOS with a titanium nitride (TiN) extended electrode.
• Investigated the quadratic dependence of threshold voltage on body potential (V_B) for electrical amplification.

Main Results:

• Achieved an apparent V_B-amplified sensitivity up to 1200 mV/pH, representing over a twentyfold enhancement.
• Demonstrated that the p-channel configuration is crucial for enhanced interfacial response compared to n-type counterparts.
• Showcased amplification of biomolecular recognition signals, such as DNA hybridization, using the developed strategy.

Conclusions:

• The body-coupled modulation strategy effectively transforms conventional PMOS FETs into ultra-sensitive electrochemical transducers.
• This approach offers a minimalistic, scalable, and ultra-low-cost pathway toward high-performance sensors.
• The findings establish a transistor-level electrical amplification mechanism for advanced chemical and biological sensing possibilities.