Silicon Substrate Thermal Expansion Mechanics in Inertial Sensors
Substrate thermal expansion creates packaging shear stress that warps MEMS proof masses, demanding central single-anchor isolation and polynomial offset calibration.
Elastic Modulus
Mechanical Property
Stress and strain relationships define the stiffness of a material within its reversible deformation range. The elastic modulus represents the ratio of applied force per unit area to the proportional change in length. Metals typically exhibit high values while polymers remain more compliant.
Metrological Measurement
Tensile testing or ultrasonic pulse velocity provide the values for engineering calculations. Calculating the elastic modulus requires precise tracking of the cross-sectional area and the gauge length during loading.
Structural Influence
Design safety factors rely on the stability of these values across the operating temperature range. An elastic modulus identifies the point where a component will return to its original shape after the load is removed. Orientation of the crystal structure in anisotropic materials like silicon results in different values depending on the axis of the applied force.
Verification Protocol
Calibration of the load cell and the extensometer ensures the accuracy of the resulting data. Reference materials with known properties verify the system performance before production batches undergo testing. Compliance with ISO or ASTM standards provides the basis for material certification.
Technicians perform these tests at controlled temperatures because the modulus typically decreases as the material warms. The resulting data points are used to generate a stress-strain curve where the linear slope defines the property.