An annular mechanical temperature compensation structure for gas-sealed capacitive pressure sensor.

Area of Science:

• Materials Science
• Sensor Technology
• Mechanical Engineering

Background:

• Capacitive pressure sensors are crucial for monitoring applications.
• Temperature fluctuations can significantly impact sensor accuracy.
• Existing compensation methods may affect sensor sensitivity.

Purpose of the Study:

• To develop a novel gas-sealed capacitive pressure sensor with an integrated temperature compensation structure.
• To investigate the effectiveness of a ring-shaped structure in suppressing thermal expansion effects.
• To evaluate the sensor's performance for human activity monitoring.

Main Methods:

• Fabrication of gas-sealed capacitive pressure sensors with and without a temperature compensation structure.
• Utilizing Au-Au diffusion bonding under nitrogen ambient (100 kPa).
• Integration of a platinum resistor for temperature sensing and simulation of capacitance-pressure/temperature characteristics.

Main Results:

• A ring-shaped structure on the diaphragm effectively suppresses the thermal expansion of sealed gas.
• Simulations accurately predicted sensor behavior, verified by fabricated and measured devices.
• Sensors with compensation (900 μm inner radius) showed significantly reduced temperature coefficients.
• Pressure sensitivity remained consistent before and after compensation (80-100 kPa range).

Conclusions:

• The novel ring-shaped compensation structure effectively mitigates temperature-induced errors in gas-sealed capacitive pressure sensors.
• The developed sensor maintains high pressure sensitivity while improving thermal stability.
• This technology offers a promising solution for accurate human activity monitoring.