Xu Pengfei, Wei Zhenyu, Jia Lu, Zhao Yongmei, Han Guowei, Si Chaowei, Ning Jin, Yang Fuhua
Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
Micromachines (Basel). 2021 Oct 29;12(11):1329. doi: 10.3390/mi12111329.
Zero-rate output (ZRO) drift induces deteriorated micro-electromechanical system (MEMS) gyroscope performances, severely limiting its practical applications. Hence, it is vital to explore an effective method toward ZRO drift reduction. In this work, we conduct an elaborate investigation on the impacts of the internal and packaging stresses on the ZRO drift at the thermal start-up stage and propose a temperature-induced stress release method to reduce the duration and magnitude of ZRO drift. Self-developed high-Q dual-mass tuning fork gyroscopes (TFGs) are adopted to study the correlations between temperature, frequency, and ZRO drift. Furthermore, a rigorous finite element simulation model is built based on the actual device and packaging structure, revealing the temperature and stresses distribution inside TFGs. Meanwhile, the relationship between temperature and stresses are deeply explored. Moreover, we introduce a temperature-induced stress release process to generate thermal stresses and reduce the temperature-related device sensitivity. By this way, the ZRO drift duration is drastically reduced from ~2000 s to ~890 s, and the drift magnitude decreases from ~0.4 °/s to ~0.23 °/s. The optimized device achieves a small bias instability (BI) of 7.903 °/h and a low angle random walk (ARW) of 0.792 °/√ h, and its long-term bias performance is significantly improved.
零速率输出（ZRO）漂移会导致微机电系统（MEMS）陀螺仪性能下降，严重限制其实际应用。因此，探索一种有效的降低ZRO漂移的方法至关重要。在这项工作中，我们详细研究了内部应力和封装应力在热启动阶段对ZRO漂移的影响，并提出了一种温度诱导应力释放方法来缩短ZRO漂移的持续时间并降低其幅度。采用自行研制的高Q值双质量音叉陀螺仪（TFG）来研究温度、频率和ZRO漂移之间的相关性。此外，基于实际器件和封装结构建立了严格的有限元仿真模型，揭示了TFG内部的温度和应力分布。同时，深入探讨了温度与应力之间的关系。此外，我们引入了一个温度诱导应力释放过程来产生热应力并降低与温度相关的器件灵敏度。通过这种方式，ZRO漂移持续时间从约2000秒大幅缩短至约890秒，漂移幅度从约0.4°/秒降至约0.23°/秒。优化后的器件实现了7.903°/小时的小偏置不稳定性（BI）和0.792°/√小时的低角度随机游走（ARW），其长期偏置性能得到显著改善。
