{"title":"A Hybrid MEMS Microphone Combining Piezoelectric and Capacitive Transduction Mechanisms","authors":"Yangyang Guan;Sina Sadeghpour;Chen Wang;Hemin Zhang;Sanjog Vilas Joshi;Milad Shojaeian;Xinyu Wu;Ruochen Ding;Christ Glorieux;Michael Kraft","doi":"10.1109/JMEMS.2025.3548927","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3548927","url":null,"abstract":"This work describes a hybrid micro-electro-mechanical-systems (MEMS) microphone based on combined piezoelectric and capacitive transduction mechanisms to enhance the sensitivity. The fabrication process for the proposed hybrid MEMS microphone is presented. A lumped element model of the prototype is derived and employed for device design. The microphone is fabricated on a silicon-on-insulator (SOI) wafer. Piezoelectric transduction is realized by a piezoelectric diaphragm consisting of a stack of Si/SiO2/Pt/PZT/Pt layers. Capacitive transduction is realized by a variable capacitor composed of a silicon device layer and a silicon handle layer. The measured sensitivities of the piezoelectric and capacitive parts of the hybrid MEMS microphone are −51.18 dB (re: 1 V/Pa) and −57.59 dB at 1 kHz, respectively. The signal-to-noise ratios (SNR) of the piezoelectric and capacitive parts of the microphone are 49.21 dB (re: 1 V/Pa) and 60.71 dB at 1 kHz, respectively. By combining dual output signals from piezoelectric and capacitive transduction mechanisms, the measured sensitivities and SNR are −47.63 dB (re: 1 V/Pa) and 52.57 dB at 1 kHz, respectively. The experimental results demonstrate that the sensitivity of the hybrid transduction microphone is improved by 3.55 dB and 9.96 dB compared to individual piezoelectric and capacitive transduction modes, respectively.[2024-0218]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 3","pages":"306-315"},"PeriodicalIF":2.5,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kunwei Zhao;Tianyou Chen;Lujia Yang;Wenjie Wu;Chenyuan Hu;Huafeng Liu;Ji Fan
{"title":"Research on Parasitic Capacitance Reduction in All-Silicon High-Precision MEMS Accelerometers","authors":"Kunwei Zhao;Tianyou Chen;Lujia Yang;Wenjie Wu;Chenyuan Hu;Huafeng Liu;Ji Fan","doi":"10.1109/JMEMS.2025.3571401","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3571401","url":null,"abstract":"Parasitic capacitances pose a critical challenge for high-precision capacitive MEMS accelerometer performance improvement, particularly for the sensitivity enhancement and self-noise minimization. For the sandwich structure MEMS accelerometer, glass top cap is commonly employed to reduce parasitic capacitances. However, considering the requirement for three-dimensional integration, an all-silicon structure is more appropriate for CMOS-MEMS integration. This study introduces a MEMS accelerometer with suspended electrodes based on low-resistivity silicon substrate. By minimizing the overlap area between the pickup electrode and the silicon substrate, the parasite capacitances are significantly reduced. Additionally, the relative motion induced capacitance change between the drive electrode and the substrate is shielded by the grounding electrode, which further mitigates the effect of parasitic capacitance on sensitivity. Experimental results demonstrate that parasitic capacitances decrease from 850 pF to 68 pF. The scale factor reaches 971 V/<italic>g</i>, making almost 4.4 times improvement. Meanwhile, by decreasing the MEMS accelerometer resonant frequency, the self-noise finally reaches 0.9 n<italic>g</i>/Hz<sup>1/2</sup>, which is approximately equivalent to the thermodynamic noise of the device. These results validate the effectiveness of the proposed method, providing a solution for achieving low-parasitic capacitance in high-performance MEMS accelerometer design. [2025-0025]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 4","pages":"422-431"},"PeriodicalIF":3.1,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Electro-Mechanical Frequency Response of a Piezo-MEMS Speaker Measured by Laser Diode Feedback Interferometry","authors":"Carlo Anelli;Sabina Merlo","doi":"10.1109/JMEMS.2025.3570666","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3570666","url":null,"abstract":"Piezo-MEMS speakers based on the inverse piezoelectric effect are becoming increasingly attractive thanks to their low power consumption and are good candidates for miniaturized devices for in-ear audio systems. In this work, we report the use of laser diode feedback interferometry, or self-mixing interferometry, for analyzing the out-of-plane vibration performance of a commercial piezo-MEMS speaker. The photodetected signal provided by the monitor photodiode contained in the laser package was acquired in the frequency domain in the band 0 – 25.6 kHz to analyze the electro-mechanical spectral response of the piezo-MEMS, under conditions of small displacements, by driving it with electrical white noise. Two resonances were detected, one at <inline-formula> <tex-math>$approx 2.8$ </tex-math></inline-formula> kHz, with low quality factor <italic>Q</i> and consistent with device specifications, and one at <inline-formula> <tex-math>$approx 21.4$ </tex-math></inline-formula> kHz, slightly above the audible frequency range for humans, with higher <italic>Q</i>. To obtain the displacement sensitivity, the MEMS was actuated with sinusoidal signals at different frequencies and amplitudes. The photodetected signal, acquired in the time domain, was used to recover the diaphragm displacement amplitude and phase delay. In particular, we were able to highlight the non-linear spectral response of the high-<italic>Q</i> resonance, under conditions of high stress and large displacement, and to reconstruct the hysteretic cycle for upward and downward frequency sweeps. The electro-mechanical frequency response detected with our extremely compact and low-cost interferometric configuration provides a complete overview of the vibration performance of the speaker, useful as a significantly easier preliminary investigation before the electro-acoustic characterization. [2024-0204]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 4","pages":"452-458"},"PeriodicalIF":3.1,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11018081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exploring Bias-Instability Noise Sources in Quadrature Error Compensation System for Mode-Split MEMS Gyroscopes","authors":"Jie Lin;Yang Zhao;Anping Qiu;Guoming Xia;Qin Shi","doi":"10.1109/JMEMS.2025.3567538","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3567538","url":null,"abstract":"In this paper, bias instability (BIS) and angle random walk (ARW) noise sources of quadrature correction for mode-split MEMS gyroscopes are first investigated. We propose a general noise model based on coupling stiffness correction that reveals the transfer mechanism of 1/f and white noise sources. The BIS with a small frequency split is mainly dominated by the electrostatic frequency-tuning voltage noise and that with a large frequency split is determined by the voltage reference noise in the quadrature loop. Due to the electrostatic frequency-tuning voltage noise, the quadrature correction system is unable to compensate for the quadrature error to zero. The BIS with quadrature correction is related to the initial quadrature error and frequency split. We find a good match between the presented model and measurements with an error of less than 15.1%. The simulation and experimental results have indicated that ARW will not be deteriorated by the quadrature compensation system. A MEMS mode-split gyroscope has achieved an ARW of <inline-formula> <tex-math>$0.029~^{circ }$ </tex-math></inline-formula>/<inline-formula> <tex-math>$surd $ </tex-math></inline-formula>h and a BIS of <inline-formula> <tex-math>$0.08~^{circ }$ </tex-math></inline-formula>/h under the initial quadrature of <inline-formula> <tex-math>$130~^{circ }$ </tex-math></inline-formula>/s and the frequency split of 85 Hz with quadrature error compensation. [2025-0014]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 4","pages":"443-451"},"PeriodicalIF":3.1,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Defect Excitation and Failure Analysis of MEMS Gas Sensors Based on FTA and RET Methods","authors":"Zenghui Hao;Minjie Zhu;Shuai Liu;Fanhong Chen;Tianxiang Liang;Kehan Zhu;Cao Xia;Yuanlin Xia;Xiaohui Du;Zhuqing Wang","doi":"10.1109/JMEMS.2025.3568374","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3568374","url":null,"abstract":"The reliability of microelectromechanical system (MEMS) gas sensors is critical for their deployment in industrial automation and environmental monitoring. However, failure mechanisms under harsh conditions remain poorly understood. This study combines Fault Tree Analysis (FTA) and Reliability Enhancement Testing (RET) to systematically investigate defect excitation in MEMS gas sensors. The FTA identifies gas-sensitive films and microheaters as weak links, while the RET reveals a 93.3% failure rate under controlled thermal and mechanical stresses. Microscopic analysis demonstrates that microcracks in the gas-sensitive film originate from mismatched thermal expansion coefficients between the film and electrodes, exacerbated by primary defects introduced during fabrication. These findings not only advance the understanding of failure mechanisms in MEMS devices but also propose design optimizations to enhance material compatibility and manufacturing processes. This work aligns with the growing demand for high-reliability MEMS sensors in applications such as biomedical diagnostics and hazardous environments monitoring, offering a roadmap for durable sensor development. [2025-0033]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 4","pages":"399-407"},"PeriodicalIF":3.1,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144756773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jun Dai;Zhiqin Wu;Zhen He;Yu Sun;Yonghua Zhao;Reo Kometani
{"title":"High-Depth FIB Etching on Silicon Sidewall: Coupling Incidence Angle and Initial Multi-Groove Surface Topography","authors":"Jun Dai;Zhiqin Wu;Zhen He;Yu Sun;Yonghua Zhao;Reo Kometani","doi":"10.1109/JMEMS.2025.3548260","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3548260","url":null,"abstract":"Focused-ion-beam (FIB) etching on the silicon sidewall surface is significant for improving the performance of micro-electro-mechanical system (MEMS) device. However, the high-depth etching on the functional surface requires the ion beam to be inclined to the surface with an initial topography, posing a notable challenge in revealing the ion beam-silicon solid interaction mechanism. In this article, we propose a molecular dynamic model for the ion-solid interaction of FIB etching on the silicon sidewall by introducing the coupling of incidence angle and initial multi-groove surface. The model is validated by conducting FIB tilted etching on a multi-groove silicon sidewall surface fabricated by inductively coupled plasma (ICP). By tilting the ion beam with an incidence angle, the target surface roughness Ra can be reduced from 126 nm to 4 nm on a <inline-formula> <tex-math>$125~mu $ </tex-math></inline-formula>m-depth silicon sidewall. We also found the inheritable effect of initial multi-groove topography on the processed sidewall surface. Results show that the inheritable effect can be reduced by decreasing the incidence angle of the ion beam. Furthermore, FIB tilted etching is applied to the sidewall micro-mirror surface of an ICP etched MEMS optical switch. By using an incidence angle of 20°, the sidewall surface with an area of <inline-formula> <tex-math>$177~mu $ </tex-math></inline-formula>m <inline-formula> <tex-math>$times 125~mu $ </tex-math></inline-formula>m is processed. The optical transmission efficiency of the MEMS switch increases from 6.9% to 34.6%. We believe this work is significant for expanding the application range of FIB etching on MEMS devices. [2024-0212]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 3","pages":"347-358"},"PeriodicalIF":2.5,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High-Order Piezoelectric Micromachined Ultrasonic Transducer With Piezoelectric Layer Trench for Ultrasound Imaging","authors":"Junxiang Cai;Yiwei Wang;Tao Wu","doi":"10.1109/JMEMS.2025.3560146","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3560146","url":null,"abstract":"This letter presents a high-order PZT PMUT (HO-PMUT) array with trenched piezoelectric layer operating at 1.78 MHz. This high-order and trench design boosts the resonant frequency to MHz without reducing the radius, while increasing vibration amplitude and Q factor compared to fundamental PMUTs. Through optimized dual electrodes, the array achieved a normalized transmitting sensitivity (TS) of 19 kPa*mm*V<sup>-1</sup>*mm<sup>−2</sup>. We demonstrated its pioneering application in ultrasound imaging by mechanically scanning a steel sample and generating a B-mode image with 7.34 dB SNR, showcasing its superior acoustic performance and potential for portable ultrasonic imaging devices. [2025-0027]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 4","pages":"359-361"},"PeriodicalIF":3.1,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11006271","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Thermally Stable, BEOL-Configured MEMS-Based One-Time Programmable (OTP) Memory for Cryogenic Embedded Application","authors":"Khanjan Miteshkumar Joshi;Manu Garg;Nitish Kumar;Yi Chiu;Pushpapraj Singh","doi":"10.1109/JMEMS.2025.3563940","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3563940","url":null,"abstract":"In this letter, we demonstrate a MEMS-based one-time programmable(OTP) memory cell integrated into the back-end-of-line (BEOL) layers of a TSMC <inline-formula> <tex-math>$0.35~mu $ </tex-math></inline-formula>m 2P4M CMOS process, designed for operation down to 4 K. This novel design eliminates the need for fusing currents, relying instead on surface-adhesion phenomena for programming. The memory cells operate with a low read voltage of 0.05 V and read current of <inline-formula> <tex-math>$80~mu $ </tex-math></inline-formula>A, ensuring low power consumption and minimal heat generation (~2.8 K). The read resistance ranges from 0.5 to 5.5 k<inline-formula> <tex-math>$Omega $ </tex-math></inline-formula> in the logic ‘1’ (ON-state) and ~2.4 T<inline-formula> <tex-math>$Omega $ </tex-math></inline-formula> in the logic ‘0’ (OFF-state), achieving an on-off ratio in the order of <inline-formula> <tex-math>$10^{9}$ </tex-math></inline-formula>. The switching energy is limited to 0.5–2.6 pJ, with a demonstrated memory retention of 4 hours at 300, 120, and 4 K. These features make it highly suitable for storing micro-operations permanently in cryogenic embedded applications.[2025-0028]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 4","pages":"362-364"},"PeriodicalIF":3.1,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wei Tian;Yuzhe Lin;Lianggong Wen;Maosen Xu;Jinghua Lin;Guoqing Hu;Jifang Tao
{"title":"Development of a MEMS Thermal Flow Sensor With High Reliability and Universality for Various Gases","authors":"Wei Tian;Yuzhe Lin;Lianggong Wen;Maosen Xu;Jinghua Lin;Guoqing Hu;Jifang Tao","doi":"10.1109/JMEMS.2025.3564169","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3564169","url":null,"abstract":"This paper presents an improved calorimetric MEMS flow sensor to meet the needs of large-scale industrial applications such as semiconductor and photovoltaics. Reliability and universality are considered the most critical factors for these fields, for which the porous silicon-based sensor was designed, fabricated and tested rigorously with eight gases. The results demonstrated that the sensor maintained nearly identical zero-flow outputs across various static gas environments (using N<sub>2</sub> as the baseline, with deviations ranging from 0.01%FS for CO to 0.69%FS for He). Moreover, well-defined conversion coefficients were established between any two gases. This characteristic enables the practical application of N<sub>2</sub>-calibrated sensors to other gases through coefficient conversion, achieving an accuracy error within 2.0%FS. In addition, the sensor can survive and maintain its sensing capabilities even during continuous SiH<sub>4</sub> combustion reactions and under heavy pollution, whereas the suspended membrane-based sensor ruptures. This innovative work makes MEMS flow sensors more convenient and reliable in complex industrial applications, potentially replacing traditional flow sensors based on capillary structures.[2025-0009]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 4","pages":"389-398"},"PeriodicalIF":3.1,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fabrication of LCE Microactuator Arrays Through Soft Lithography With Surface Alignment","authors":"Ke Li;Jae-Jun Kim;Jayer Fernandes;Hongrui Jiang","doi":"10.1109/JMEMS.2025.3546852","DOIUrl":"https://doi.org/10.1109/JMEMS.2025.3546852","url":null,"abstract":"Liquid crystal elastomers (LCEs) offer potentially programmable actuation through precise molecular alignment, making them ideal for microactuators in soft robotics and optical systems. However, achieving precise microscale alignment for LCE actuator arrays through scalable microfabrication approaches has been challenging. This letter introduces a low-cost surface alignment method to fabricate LCE microactuator arrays, reducing the dependency on expensive equipment, improving accessibility and manufactuarability compared to existing studies using field-assisted alignment methods. Thermal actuation tests demonstrated strong thermal responsiveness and stability. Our method offers a superior approach to integrating LCE microactuator arrays with modern microfabrication processes, promising multitudinous applications in MEMS and beyond.[2024-0192]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"34 3","pages":"241-243"},"PeriodicalIF":2.5,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}