Wafer-Level-Based Open-Circuit Sensitivity Model from Theoretical ALEM and Empirical OSCM Parameters for a Capacitive MEMS Acoustic Sensor
Wafer-Level-Based Open-Circuit Sensitivity Model from Theoretical ALEM and Empirical OSCM Parameters for a Capacitive MEMS Acoustic Sensor
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基于理论 ALEM 和经验 OSCM 参数的电容式 MEMS 声学传感器的基于晶圆级的开路灵敏度模型
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发表时间：
2019
期刊：
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通讯作者：
S. Moon
中科院分区：
文献类型：
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作者：
Jaewoo Lee;J. Im;Jeong;Sol;S. Moon
我们提出了一种简单、准确的开路灵敏度模型，该模型基于分析计算的集总参数和经验提取的集总参数，使电容式声传感器能够在晶圆级的频域中进行有效的表征。我们的混合模型主要由两个关键策略组成：近似线性化电场法（ALEM）和开路短路校准法（OSCM）。分析ALEM可以将固有电容与声学传感器本身的电容分开，而经验OSCM则在不包括薄膜的额外测试样本的基础上，可以从整个传感器芯片中提取有源部分的电容值。有限元仿真验证了模型在晶胞误差2%范围内的有效性。动态开路灵敏度是根据基于等效电路的集总参数进行建模的，从而得出偏置条件下的建模谐振频率。因此，这种混合模型消除了复杂的读出集成电路（ROIC）集成过程，不仅简化了表征过程，而且还提高了灵敏度的准确性，因为它考虑了膜片和背板中每个蚀刻孔之间的边缘场效应。
We present a simple, accurate open-circuit sensitivity model based on both analytically calculated lumped and empirically extracted lumped-parameters that enables a capacitive acoustic sensor to be efficiently characterized in the frequency domain at the wafer level. Our mixed model is mainly composed of two key strategies: the approximately linearized electric-field method (ALEM) and the open- and short-calibration method (OSCM). Analytical ALEM can separate the intrinsic capacitance from the capacitance of the acoustic sensor itself, while empirical OSCM, on the basis of one additional test sample excluding the membrane, can extract the capacitance value of the active part from the entire sensor chip. FEM simulation verified the validity of the model within an error range of 2% in the unit cell. Dynamic open-circuit sensitivity is modelled from lumped parameters based on the equivalent electrical circuit, leading to a modelled resonance frequency under a bias condition. Thus, eliminating a complex read-out integrated circuit (ROIC) integration process, this mixed model not only simplifies the characterization process, but also improves the accuracy of the sensitivity because it considers the fringing field effect between the diaphragm and each etching hole in the back plate.