硅微半球陀螺结构与制造方法及其接口电路设计

Structure and Manufacturing Method of Silicon Micro Hemispherical Gyroscope and Interface Circuit Design

针对微半球陀螺加工对称性差的问题,提出了自对准球形电极的多晶硅半球谐振器架构,实现了电极与谐振器相同曲率的一体化成型工艺,从而确保了谐振器的对称性。为使谐振器具有较大的驱动电容和检测电容,电极和外壳之间的间隙由牺牲层制成,电容间隙均匀且达到了1.5μm。接口控制电路采用基于FPGA的数字化设计,发挥了数字系统信噪比高和开发灵活的优势,实现了开环扫频、锁相环、自动增益控制、交流正交抑制等核心功能。实验结果表明,该陀螺的品质因数达到了42554,谐振频率为5.130kHz和5.128kHz,零偏稳定性达到了3.4 (°)/h。

Aiming at the difficulty of symmetrical manufacturing of micro-hemispherical gyroscopes,this paper proposes a polysilicon hemispherical resonator structure with self-aligned spherical electrodes,which realizes an integrated molding process with the same curvature of the electrode and the resonator.Therefore,the symmetry of the resonator and the possibility of mass production are guaranteed.In order to make the driving and sensing capacitance of the resonator large enough,the gap between the electrodes and the shell is made of a sacrificial layer,and the capacitance gap is sufficiently uniform and reaches 1.5μm.The interface control circuit is digitally designed based on FPGA,which gives full play to the advantages of digital system high signal-to-noise ratio and development flexibility.It implements core functions such as open-loop frequency sweeping,phase-locked loop,automatic gain control,and AC quadrature error nulling,and improves the performance indicators of the gyroscope.Experimental results show that the quality factor of the gyro system reaches 42554,the resonance frequencies are 5.130 kHz and5.128 kHz,and the bias instability reaches 3.4°/h.