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A CMOS-Compatible, Low-Noise ISFET Based on High Efficiency Ion-Modulated Lateral-Bipolar Conduction
1Institute of Electronics Engineering, National Tsing Hua University, 30013 HsinChu, Taiwan; E-Mail: d935040@oz.nthu.edu.tw (S.-R.C).
Sensors (Basel, Switzerland)
|March 13, 2012
Summary
This study introduces a novel Ion-Sensitive Field-Effect Transistor (ISFET) biosensor that uses lateral-bipolar conduction to significantly reduce low-frequency noise. This innovation improves the signal-to-noise ratio for biosensing applications, such as pH sensing, by over five times.
Area of Science:
- Electronics
- Biosensors
- Materials Science
Background:
- Ion-sensitive, field-effect transistors (ISFETs) are widely used biosensors.
- Their performance is often limited by intrinsic low-frequency noise, impacting signal-to-noise ratio.
- There is a need for ISFET designs with improved noise characteristics.
Purpose of the Study:
- To present a novel ISFET design utilizing lateral-bipolar conduction to reduce low-frequency noise.
- To enhance conduction efficiency through a specific layout design.
- To identify optimal biasing conditions for low-noise ISFET operation.
Main Methods:
- Development of an ISFET incorporating lateral-bipolar conduction.
- Implementation of a specific layout design to improve conduction efficiency.
- Utilizing a die-level post-CMOS process to enable direct ion modulation of lateral-bipolar current.
- Controlling ISFET operation modes and noise performance via gate-to-bulk voltage variation.
Main Results:
- The novel ISFET design effectively reduces low-frequency noise.
- Conduction efficiency is enhanced by the specific layout.
- The ISFET is compatible with standard CMOS technology and allows direct ion modulation.
- Optimal biasing conditions for low-noise applications were identified.
Conclusions:
- The developed ISFET demonstrates significantly reduced low-frequency noise.
- The signal-to-noise ratio of the ISFET as a pH sensor is improved by more than five times under optimal biasing.
- This technology offers a promising advancement for high-performance biosensing.
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