An Analysis of Temperature Variation Effect on Response and Performance of Capacitive Microaccelerometer Inertial Sensors

摘要

There are many designed and manufactured microdevices including sensors and actuators. The most popular and widely used commercially available examples of these are rotational velocity sensors and linear acceleration sensors. These are commonly referred to as inertial sensors, because their principle of operation is based on the displacement of a solid mass under external force. Because of some limitation, like small size, fabrication methods and fragility, these devices must have as simple of a geometry (structure) as possible. However, even in such simple sensors we can differentiate substructures that behave in some characteristic way. Of course, very important roles are played by the sensing mechanism itself and the geometry, particularly of the substructures included in device, which are strongly determined by phenomena/physics used for sensing physical quantity. In some type of sensors and substructures, deformation is an undesirable effect, such as in capacitive sensors, while in other sensors, such as piezoresistive ones, it is the principle of operation. Obviously, temperature variations can cause changes to geometrical dimensions due to expansions; therefore it influences sensor operation and potentially degrades stability and performance. In this paper, the effects of temperature variations on the output accelerometer performance of the inertial sensors are determined, and thermal deformation of this kind of device is analyzed. The variations of the output capacitances of considered for inertial sensor as well as the variation of resonance frequency and capacitance due to temperature fluctuations, which are simulated, calculated and discussed here.These were the objectives of this work:1.Assess deformation (extension) of structure along with temperature growth with reference temperature assumed. This is the basis for further assessment of measurement errors introduced by extension and therefore- capacitances deviations.2.Assess the influence of temperature variation on particular modes of this device.3.Assess the influence of temperature variation on capacitance shift, which introduces measurement inaccuracies.