A Micromachined Piezoresistive Pressure Sensor with a Shield Layer

Area of Science:

• Materials Science
• Electrical Engineering
• Sensor Technology

Background:

• Conventional piezoresistive pressure sensors face challenges with electrical field interference and temperature sensitivity.
• These factors can lead to drift and reduced accuracy in sensor readings.
• Improving sensor stability is crucial for reliable pressure measurement applications.

Purpose of the Study:

• To introduce and evaluate a novel piezoresistive pressure sensor design.
• To investigate the effectiveness of an n-type shield layer in mitigating electrical field effects and temperature sensitivity.
• To demonstrate enhanced stability and performance in a new sensor architecture.

Main Methods:

• Fabrication of the proposed piezoresistive pressure sensor using bulk-micromachining techniques.
• Integration of an n-type shield layer covering p-type piezoresistors.
• Experimental characterization of sensor performance, including sensitivity and non-linearity.
• Numerical simulation and experimental validation of the shield layer's role.

Main Results:

• The fabricated sensor achieved a sensitivity of 0.022 mV/V/kPa.
• A maximum non-linearity of 0.085% Full Scale (FS) was recorded within a 1 MPa pressure range.
• Experimental investigations confirmed the shield layer's ability to reduce drift from electrical fields and temperature variations.
• The n-type shield layer effectively minimized the impact of external electrical fields on piezoresistors.

Conclusions:

• The developed piezoresistive pressure sensor with an n-type shield layer demonstrates significantly improved stability.
• The shield layer is a key innovation for reducing electrical field interference and temperature sensitivity.
• This design offers a promising solution for high-accuracy and stable pressure sensing applications.