Li Jiacheng, Feng Rui, Wang Xiaoyi, Cao Huiliang, Gong Keru, Xie Huikai
School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China.
East China Institute of Photo-Electron lC, Bengbu 233030, China.
Micromachines (Basel). 2024 Sep 22;15(9):1173. doi: 10.3390/mi15091173.
This paper reports the design, fabrication, and characterization of a MEMS capacitive accelerometer with an asymmetrical comb finger arrangement. By optimizing the ratio of the gaps of a rotor finger to its two adjacent stator fingers, the sensitivity of the accelerometer is maximized for the same comb finger area. With the fingers' length, width, and depth at 120 μm, 4 μm, and 45 μm, respectively, the optimized finger gap ratio is 2.5. The area of the proof mass is 750 μm × 560 μm, which leads to a theoretical thermomechanical noise of 9 μg/√Hz. The accelerometer has been fabricated using a modified silicon-on-glass (SOG) process, in which a groove is pre-etched into the glass to hold the metal electrode. This SOG process greatly improves the silicon-to-glass bonding yield. The measurement results show that the resonant frequency of the accelerometer is about 2.05 kHz, the noise floor is 28 μg/√Hz, and the nonlinearity is less than 0.5%.
本文报道了一种具有非对称梳齿结构的微机电系统（MEMS）电容式加速度计的设计、制造与特性。通过优化转子齿与其两个相邻定子齿之间的间隙比，在梳齿面积相同的情况下，加速度计的灵敏度得以最大化。当齿的长度、宽度和深度分别为120μm、4μm和45μm时，优化后的齿间隙比为2.5。质量块的面积为750μm×560μm，这导致理论热机械噪声为9μg/√Hz。该加速度计采用改进的玻璃上硅（SOG）工艺制造，其中在玻璃中预先蚀刻出一个凹槽以固定金属电极。这种SOG工艺大大提高了硅与玻璃的键合良率。测量结果表明，该加速度计的谐振频率约为2.05kHz，本底噪声为28μg/√Hz，非线性小于0.5%。
