低热机械噪声的梳齿式加速度计

Low Thermal-mechanical Noise MEMS Accelerometer

文中介绍了一种基于低噪声梳齿变面积型加速度计。采用体硅加工工艺,利用SOI材料30μm顶层硅制造垂直梳齿,梳齿数目达200对,提高了初始电容,能够充分利用尺寸空间,获得具有低噪特性的加速度计。该种形式的加速度计不需要真空封装,也不需要制作阻尼孔就能满足低噪声要求。器件采用三层材料,利用硅-玻璃键合和BCB键合实现,能够有效提高成品率,并给出了成功流片后得到的SEM照片。最后,对器件进行了频谱响应曲线的测试,测试得到器件在非真空封装及无阻尼孔情况下Q值高达156.95。测试结果表明该器件的设计简化了制造工艺,降低了成本,同时得到提高了Q值,能够降低热机械噪声。

This paper presented a low noise accelerometer based on comb area changing. With bulk silicon process, it used the top layer to form comb finger and the bottom layer to form mass bulk. The number of comb fingers was increased and the capacitance was improved. The paper provided the process of producing the device and got a low noise accelerometer which can be produced easier and did not have to be packaged in vacuum circumstance. The Q factor is high even there is no damp holes in the mass bulk. The test results prove that the device can get high Q factor and decrease the thermal-mechanical noise.