Temperature Effect on the Mechanical Transmission Coefficient of a Microoptoelectromechanical Accelerometer

The treatise studies a temperature effect on the microoptoelectromechanical (MOEMS) accelerometer with an optical measuring transducer based on evanescent wave coupling. The work investigates the temperature sensitivity of the mechanical part of the accelerometer in a temperature range from minus $65^{\circ} \mathrm{C}$ to plus $125^{\circ} \mathrm{C}$. The temperature alteration induces stresses in the mechanical structure. Maximum mechanical stresses emerging in the structure at a temperature of minus $65^{\circ} \mathrm{C}$ reach 556.61 MPa for the layer of aluminum that can be used for in-package wire bonding. However, these stresses are smaller than the admissible value for aluminum (690 MPa). The maximum stresses in residual layers of the mechanical structure are several times smaller than those in the aluminum layer. At different temperatures, the eigenfrequency of the accelerometer also changes, which alters its mechanical transmission coefficient. The temperature sensitivity of normalized mechanical transmission coefficient per $1^{\circ} \mathrm{C}$ amounts to $0.00012{ }^{\circ} \mathrm{C}^{-1}$. To compensate the temperature effect on the mechanical transmission coefficient, various design schemes can be used and the output signal can be adjusted according to the temperature sensor readings.