利用有限元方法, 仿真分析了深反应离子刻蚀工艺造成的折叠梁宽度误差对电容式微加速度计温度漂移的影响。在存在工艺误差和保证微加速度计灵敏度恒定的前提下, 增大了折叠梁设计宽度, 计算了不同宽度下微加速度计的温度漂移量。结果表明: 刻蚀工艺误差越大, 微加速度计温度漂移量越大。折叠梁设计宽度为4.5 μm和6.5 μm时, 最大温度漂移量分别为2.42 mg/℃和1.71 mg/℃, 因此通过适当地增大设计尺寸, 可以有效地减小微加速度计的温度漂移量。

Dimension uncertainty inevitably occurs in almost every fabrication of micro structure due to its small size and uniformity of material. The dimension error, however, will result in the asymmetry of the sensitive structure. The unsymmetrical structure will change the distribution of the thermal stress when the micro sensors are subjected to changed temperature and further impact the thermal stability of devices which is characterized by the quantity of thermal drift. This study investigates the effects of fabrication error on the thermal drift of a comb capacitive micro accelerometer fabricated by deep reactive ion etching(DRIE) process. The accelerometers with supporting folded beams width error ranging from the ideal layout design to the actual fabricated dimension are modeled to simulate the deformation of sensitive component induced by temperature change. The thermal drifts are acquired by the calculation of the differential capacitance of the deformed structure. In order to reduce the thermal drift induced by the fabrication error, the design dimension of the beam width is enlarged under the premise of constant sensitivity of the accelerometer. The calculated results indicate that the supporting beam fabrication error will significantly affect the thermal drift of the capacitive micro accelerometers and an increased design dimension of the beam width can improve the symmetry of the sensor, and then reduce the thermal drift.