A Review of Readout Circuit Schemes Using Silicon Nanowire Ion-Sensitive Field-Effect Transistors for pH-Sensing...

Area of Science:

• Nanotechnology
• Electronics Engineering
• Biomedical Engineering

Background:

• Silicon nanowire (SiNW) ion-sensitive field-effect transistors (ISFETs) are promising for pH sensing due to their high surface-to-volume ratio and CMOS compatibility.
• Existing SiNW ISFET biosensors face challenges in readout circuit performance, including sensitivity and linearity.

Purpose of the Study:

• To review design approaches for SiNW ISFET-based pH sensing schemes.
• To analyze fabrication processes, device structures, and theoretical performance parameters of SiNW ISFETs.
• To propose an improved readout circuit for enhanced SiNW ISFET biosensor performance.

Main Methods:

• Review of major fabrication processes and device structures for SiNW ISFETs.
• Theoretical analysis of key performance parameters (sensitivity, linearity, noise immunity) in readout circuits.
• Quantitative evaluation of existing N-type and P-type current-mirror-based readout circuits.
• Proposal of a modified N-type readout scheme with operational amplifier and negative feedback.

Main Results:

• SiNW ISFETs offer advantages like fast response times and CMOS integration potential.
• Conventional N-type circuits exhibit limitations in sensitivity.
• The proposed modified N-type readout scheme enhances gain control, linearity, and noise immunity.
• The new design maintains stability while improving overall performance.

Conclusions:

• SiNW ISFETs are suitable for advanced pH sensing applications.
• The proposed readout circuit design addresses limitations of conventional approaches.
• This work contributes to the advancement of SiNW ISFET-based readout circuits for biosensing.