Silicon Based Coplanar Capacitive Device for Liquid Sensor Applications.

Area of Science:

• Materials Science and Engineering
• Electrical Engineering
• Sensor Technology

Background:

• Silicon-based sensor devices are crucial for advancing integrated smart sensor technologies.
• Capacitive sensor devices offer a versatile platform for diverse applications.
• Accurate modeling of capacitive sensors, including substrate effects, is essential for reliable performance.

Purpose of the Study:

• To present an interdigitated coplanar capacitive sensor fabricated on a silicon substrate.
• To demonstrate the sensor's potential for liquid sensing applications.
• To develop and validate a comprehensive capacitance model accounting for parasitic substrate capacitances.

Main Methods:

• Fabrication of an interdigitated coplanar capacitive sensor on a silicon substrate.
• Development of a detailed capacitance model incorporating parasitic substrate capacitances.
• Theoretical validation using finite-element simulations and experimental validation with fabricated devices.
• Integration of a polydimethylsiloxane (PDMS) mold for liquid sample collection.

Main Results:

• Successful fabrication and demonstration of a silicon-based interdigitated capacitive sensor.
• Validation of the developed capacitance model through simulations and experimental data.
• Demonstration of the sensor's sensitivity to changes in the dielectric constant of the medium, indicating liquid sensing capability.

Conclusions:

• The presented interdigitated coplanar capacitive sensor on silicon is a viable technology for liquid sensing.
• The developed capacitance model accurately predicts device behavior, including substrate effects.
• Guidelines for enhancing sensor performance have been identified for future development.