Failure Analysis and Optimized Simulation Design of Silicon Micromechanical Resonant Accelerometers

Area of Science:

• Materials Science
• Mechanical Engineering
• Physics

Background:

• Silicon micromechanical resonant accelerometers are crucial for precise motion sensing.
• Frequency instability and failure under environmental stresses limit their performance.
• Understanding stress-induced effects is vital for improving accelerometer reliability.

Purpose of the Study:

• To investigate the state characteristics of micromechanical resonant accelerometers under temperature and vibration stresses.
• To identify the primary causes of frequency instability and failure.
• To propose a design solution to enhance accelerometer performance and durability.

Main Methods:

• Theoretical analysis of material properties and stress-strain relationships.
• Finite element simulation to model accelerometer behavior under various conditions.
• Experimental validation of simulation results (implied).

Main Results:

• Temperature variations alter silicon's Young's modulus, causing resonance frequency shifts (-1.364 Hz/°C).
• Residual stresses from temperature changes significantly impact resonance frequency (5.43 Hz/MPa tensile, -5.25 Hz/MPa compressive).
• Thermal expansion leads to bonding wire failure, with peak stress increasing dramatically (up to 1.28 GPa).
• Vibration stress causes structural fracture and interlayer peeling.
• The proposed isolation frame design reduces temperature-induced frequency effects (34% tensile, 15% compressive) and vibration-induced stress (up to 71.3%).

Conclusions:

• Environmental stresses, particularly temperature and vibration, critically affect silicon micromechanical resonant accelerometer performance and lifespan.
• The proposed isolation frame design effectively mitigates frequency instability and structural failure.
• This research provides a pathway for developing more robust and reliable accelerometers for demanding applications.