A low-cost CMOS-MEMS piezoresistive accelerometer with large proof mass

Area of Science:

• Microelectromechanical Systems (MEMS)
• Solid-state Physics
• Sensor Technology

Background:

• Piezoresistive accelerometers are crucial for inertial sensing.
• Integrating MEMS with CMOS technology offers miniaturization and cost benefits.
• Developing high-sensitivity, low-power accelerometers remains an active research area.

Purpose of the Study:

• To report a novel CMOS-MEMS piezoresistive accelerometer with enhanced sensitivity.
• To investigate the use of a bulk single-crystal silicon substrate for increased proof mass.
• To analyze the impact of self-heating on sensor performance.

Main Methods:

• Fabrication using ON Semiconductor 0.5 μm CMOS technology with post-CMOS Deep Reactive Ion Etching (DRIE).
• Utilization of inherent CMOS polysilicon thin film as the piezoresistive sensing material.
• Construction of a full Wheatstone bridge using three metal layers for signal conditioning.

Main Results:

• Achieved a sensitivity of 0.077 mV/g prior to amplification.
• Demonstrated low operating power consumption of 1.5 mW.
• Incorporated a bulk single-crystal silicon substrate in the proof mass to boost sensitivity.

Conclusions:

• The developed CMOS-MEMS accelerometer offers a cost-effective solution for high-sensitivity inertial sensing.
• The integration of SCS substrate effectively enhances sensor sensitivity.
• Further analysis of self-heating effects is crucial for optimizing performance in advanced applications.