Light Detection and Ranging (LiDAR) devices are critical for constructing three-dimensional scenes around vehicles, making them essential for automatic and intelligent driving systems. Micro-Electro-Mechanical Systems (MEMS) electromagnetic micromirrors have significantly developed MEMS-based LiDAR due to their inherent advantages. However, the traditional electromagnetic micromirrors, typically actuated by a single coil, experience crosstalk between the slow and fast axes. In this study, we introduce a dual-axis electromagnetic micromirror designed to eliminate this crosstalk. Unlike conventional micromirrors, our model features two distinct driving coils placed over the balance gimbal and reflecting mirror to control the slow and fast axes independently. This micromirror, with a 7.2 mm-diameter circular mirror, is manufactured using silicon on insulation (SOI) technology and incorporates a low-residual-stress packaging design. Our tests show that the scanning images from the fast axis of the proposed micromirror exhibit no crosstalk, achieving a significant improvement over traditional designs. Performance evaluation through geometric optical testing revealed that the slow axis resonates at 132 Hz and achieves a deflection angle of 36.3° with a quality factor of 26.9, while the fast axis resonates at 712 Hz, reaching 35.2° with a quality factor of 53.5. Additionally, the angle sensor performance was assessed, showing outputs that are highly proportional to the optical angles, recorded at 13.04 mV/deg and 9.80 mV/deg for the slow and fast axes, respectively.[2024-0084]
{"title":"A 2D MEMS Crosstalk-Free Electromagnetic Micromirror for LiDAR Application","authors":"Xiao-Yong Fang;Er-Qi Tu;Jun-Feng Zhou;Ang Li;Wen-Ming Zhang","doi":"10.1109/JMEMS.2024.3415156","DOIUrl":"10.1109/JMEMS.2024.3415156","url":null,"abstract":"Light Detection and Ranging (LiDAR) devices are critical for constructing three-dimensional scenes around vehicles, making them essential for automatic and intelligent driving systems. Micro-Electro-Mechanical Systems (MEMS) electromagnetic micromirrors have significantly developed MEMS-based LiDAR due to their inherent advantages. However, the traditional electromagnetic micromirrors, typically actuated by a single coil, experience crosstalk between the slow and fast axes. In this study, we introduce a dual-axis electromagnetic micromirror designed to eliminate this crosstalk. Unlike conventional micromirrors, our model features two distinct driving coils placed over the balance gimbal and reflecting mirror to control the slow and fast axes independently. This micromirror, with a 7.2 mm-diameter circular mirror, is manufactured using silicon on insulation (SOI) technology and incorporates a low-residual-stress packaging design. Our tests show that the scanning images from the fast axis of the proposed micromirror exhibit no crosstalk, achieving a significant improvement over traditional designs. Performance evaluation through geometric optical testing revealed that the slow axis resonates at 132 Hz and achieves a deflection angle of 36.3° with a quality factor of 26.9, while the fast axis resonates at 712 Hz, reaching 35.2° with a quality factor of 53.5. Additionally, the angle sensor performance was assessed, showing outputs that are highly proportional to the optical angles, recorded at 13.04 mV/deg and 9.80 mV/deg for the slow and fast axes, respectively.[2024-0084]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 5","pages":"559-567"},"PeriodicalIF":2.5,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141506501","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}
This paper presents a general instability model of mode-split MEMS gyroscopes. The proposed model can accurately predict the bias instability of a given device based on the applied angular rate and system parameters. The model consists of two noise models: bias instability and scale factor instability. Four flicker noise sources are considered that are the most significant contributors. These include phase flicker noise of the drive capacitance to voltage converter, sense analog-to-digital (ADC) scale factor instability, proof mass voltage flicker noise, and additive flicker noise. All the noise contributors are thoroughly analyzed and experimentally characterized on four triaxial research devices. Based on the results of the experimental characterization, the proposed scale factor and bias instability models are verified against the measurement data. We find a good match between the presented model and measurements. As anticipated by the proposed model, a reduction of the phase flicker noise of the drive capacitance to voltage converter has led to up to 50% improvement in bias instability.[2024-0018]
{"title":"Root-Causes of Bias Instability Noise in Mode-Split MEMS Gyroscopes","authors":"Miloš Vujadinović;Tobias Hiller;Thorsten Balslink;Mourad Elsobky;Lukas Blocher;Alexander Buhmann;Thomas Northemann;Bhaskar Choubey","doi":"10.1109/JMEMS.2024.3406584","DOIUrl":"10.1109/JMEMS.2024.3406584","url":null,"abstract":"This paper presents a general instability model of mode-split MEMS gyroscopes. The proposed model can accurately predict the bias instability of a given device based on the applied angular rate and system parameters. The model consists of two noise models: bias instability and scale factor instability. Four flicker noise sources are considered that are the most significant contributors. These include phase flicker noise of the drive capacitance to voltage converter, sense analog-to-digital (ADC) scale factor instability, proof mass voltage flicker noise, and additive flicker noise. All the noise contributors are thoroughly analyzed and experimentally characterized on four triaxial research devices. Based on the results of the experimental characterization, the proposed scale factor and bias instability models are verified against the measurement data. We find a good match between the presented model and measurements. As anticipated by the proposed model, a reduction of the phase flicker noise of the drive capacitance to voltage converter has led to up to 50% improvement in bias instability.[2024-0018]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 5","pages":"514-523"},"PeriodicalIF":2.5,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141506543","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}
Pub Date : 2024-06-24DOI: 10.1109/JMEMS.2024.3405456
Jian Zhao;Heng Zhong;Rongjian Sun;Najib Kacem;Ming Lyu;Zeyuan Dong;Pengbo Liu
The snap through phenomenon of curved beam structures offers the possibility for designing high-performance filters, however, superharmonic resonances outside the filter’s passband are difficult to be attenuated. Therefore, a two-stage bandpass filter incorporating two electromagnetically coupled curved microbeams is designed, which possesses excellent specifications of sharp switching in the stopband and flat bandwidth compared to single curved-beam based filter. The reduced-order model considering the nonlinear electromagnetic forces and geometric nonlinearities is established, and discretized using the Galerkin method. Then, the resulting static and dynamic reduced order models are numerically solved. Extensive numerical simulation results show that the improved filter has a rectangular coefficient close to 1.0, a passband ripple of 0.2 dB, and a bandwidth ratio of 14.8%, which drastically reduces the stopband interference to 10% of the passband signal. Finally, the effects of DC voltage, AC voltage and coupling strength on the center frequency and bandwidth are parametrically investigated, where the center frequency can be tuned between 23.81 kHz and 25.16 kHz and the bandwidth covers the frequency range from 22.46 kHz to 26.05 kHz. [2024-0054]
{"title":"A Tunable Two-Stage Bandpass Filter Incorporating Two Electromagnetically Coupled Curved Beams","authors":"Jian Zhao;Heng Zhong;Rongjian Sun;Najib Kacem;Ming Lyu;Zeyuan Dong;Pengbo Liu","doi":"10.1109/JMEMS.2024.3405456","DOIUrl":"10.1109/JMEMS.2024.3405456","url":null,"abstract":"The snap through phenomenon of curved beam structures offers the possibility for designing high-performance filters, however, superharmonic resonances outside the filter’s passband are difficult to be attenuated. Therefore, a two-stage bandpass filter incorporating two electromagnetically coupled curved microbeams is designed, which possesses excellent specifications of sharp switching in the stopband and flat bandwidth compared to single curved-beam based filter. The reduced-order model considering the nonlinear electromagnetic forces and geometric nonlinearities is established, and discretized using the Galerkin method. Then, the resulting static and dynamic reduced order models are numerically solved. Extensive numerical simulation results show that the improved filter has a rectangular coefficient close to 1.0, a passband ripple of 0.2 dB, and a bandwidth ratio of 14.8%, which drastically reduces the stopband interference to 10% of the passband signal. Finally, the effects of DC voltage, AC voltage and coupling strength on the center frequency and bandwidth are parametrically investigated, where the center frequency can be tuned between 23.81 kHz and 25.16 kHz and the bandwidth covers the frequency range from 22.46 kHz to 26.05 kHz. [2024-0054]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 4","pages":"482-494"},"PeriodicalIF":2.5,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529499","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}
Pub Date : 2024-06-11DOI: 10.1109/JMEMS.2024.3409155
Kevin R. Talley;Benjamen N. Taber;Rick Morton;Steve K. Brainerd;Austin J. Fox
Optimization of bulk acoustic wave (BAW) resonator border ring (BR) thicknesses and widths has traditionally been done using multi-wafer splits, often in combination with modeling techniques. Here we describe a single-wafer, two-factor experimental design with 21 distinct experimental regions where we employed custom ion trim and photoresist exposure procedures to optimize BR thickness and width. This resulted in a methodology for optimizing device performance in a manner that reduces the time and cost compared to traditional methods. Though we applied this experimental design to investigating the impact of BR thickness and width on radio frequency BAW filter passband performance, it is generalizable, thereby enabling single-wafer multi-factor experimental designs across an array of device components. [2024-0039]
{"title":"Single-Wafer Combinatorial Optimization of Border Rings for Bulk Acoustic Wave Filters","authors":"Kevin R. Talley;Benjamen N. Taber;Rick Morton;Steve K. Brainerd;Austin J. Fox","doi":"10.1109/JMEMS.2024.3409155","DOIUrl":"10.1109/JMEMS.2024.3409155","url":null,"abstract":"Optimization of bulk acoustic wave (BAW) resonator border ring (BR) thicknesses and widths has traditionally been done using multi-wafer splits, often in combination with modeling techniques. Here we describe a single-wafer, two-factor experimental design with 21 distinct experimental regions where we employed custom ion trim and photoresist exposure procedures to optimize BR thickness and width. This resulted in a methodology for optimizing device performance in a manner that reduces the time and cost compared to traditional methods. Though we applied this experimental design to investigating the impact of BR thickness and width on radio frequency BAW filter passband performance, it is generalizable, thereby enabling single-wafer multi-factor experimental designs across an array of device components. [2024-0039]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 4","pages":"468-472"},"PeriodicalIF":2.5,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884716","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}
Pub Date : 2024-06-05DOI: 10.1109/JMEMS.2024.3405430
Guangpeng Chen;Zhan Zhan;Xiaowen Wang;Zuhang Zhou;Lingyun Wang
This paper reports a strong robustness MEMS QMG with the parallel coupled structure design, for the first time. The motions of the four masses of the gyroscope in the drive and sense directions are coupled and connected through different rings to achieve the parallel coupled effect. We demonstrated that the parallel coupled QMG has stronger robustness by numerical analysis, FEA and experiments. We study the kinematic equations of the parallel coupled QMG and compare it with the serial coupled QMG to analyze the effect of the difference in stiffness matrices and damping mismatch on the gyroscope performance and carry out numerical analyses under the conditions of stiffness mismatch and external vibration, and the results show that the parallel coupled QMG has stronger stiffness robustness and vibration robustness. We applied accelerations of different magnitudes and directions to the parallel and serial QMG to simulate the external loads, and the results show that the bandwidth of the parallel QMG is almost unaffected by the acceleration. We fabricated the parallel coupled QMG prototype using the SOG process, and designed circuits to test the performance. The results indicate that the gyroscope is sensitive to small input angles with $mathrm {0.0603 ^{circ }/s/surd Hz}$ ARW and 0.0135∘/s BI at 162 Hz frequency mismatch and $30~^{circ }$ C temperature compensation. Moreover, the frequency and quality factor of the parallel QMG are little affected by temperature and the bandwidth remains almost constant with good temperature robustness. These results indicate that the parallel structure has the potential to deliver better performance. [2024-0021]
{"title":"Strong Robustness Quad Mass Gyroscope With the Parallel Coupled Structure Design","authors":"Guangpeng Chen;Zhan Zhan;Xiaowen Wang;Zuhang Zhou;Lingyun Wang","doi":"10.1109/JMEMS.2024.3405430","DOIUrl":"10.1109/JMEMS.2024.3405430","url":null,"abstract":"This paper reports a strong robustness MEMS QMG with the parallel coupled structure design, for the first time. The motions of the four masses of the gyroscope in the drive and sense directions are coupled and connected through different rings to achieve the parallel coupled effect. We demonstrated that the parallel coupled QMG has stronger robustness by numerical analysis, FEA and experiments. We study the kinematic equations of the parallel coupled QMG and compare it with the serial coupled QMG to analyze the effect of the difference in stiffness matrices and damping mismatch on the gyroscope performance and carry out numerical analyses under the conditions of stiffness mismatch and external vibration, and the results show that the parallel coupled QMG has stronger stiffness robustness and vibration robustness. We applied accelerations of different magnitudes and directions to the parallel and serial QMG to simulate the external loads, and the results show that the bandwidth of the parallel QMG is almost unaffected by the acceleration. We fabricated the parallel coupled QMG prototype using the SOG process, and designed circuits to test the performance. The results indicate that the gyroscope is sensitive to small input angles with \u0000<inline-formula> <tex-math>$mathrm {0.0603 ^{circ }/s/surd Hz}$ </tex-math></inline-formula>\u0000 ARW and 0.0135∘/s BI at 162 Hz frequency mismatch and \u0000<inline-formula> <tex-math>$30~^{circ }$ </tex-math></inline-formula>\u0000C temperature compensation. Moreover, the frequency and quality factor of the parallel QMG are little affected by temperature and the bandwidth remains almost constant with good temperature robustness. These results indicate that the parallel structure has the potential to deliver better performance. [2024-0021]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 4","pages":"408-418"},"PeriodicalIF":2.5,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884708","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}
Pub Date : 2024-06-04DOI: 10.1109/JMEMS.2024.3404420
Zichen Tang;Giovanni Esteves;Sean Yen;Travis R. Young;Michael David Henry;Loren Gastian;Christopher Nordquist;Roy H. Olsson
In this paper, spurious mode suppression methods for Al0.72Sc0.28N Lamb wave resonators and filters using the lowest order symmetric (S0) Lamb wave were meticulously studied and exercised. By adopting the method formally known as apodization, which inherently incorporates controlled finger lengths and bus-interdigitated transducer (IDTs) separation, in conjunction with a full-width anchor and an aperture-matched release pit geometry, the complete eradication of spurious mode responses in the resonator passband was demonstrated. Owing to the high piezoelectric coefficient brought by the scandium alloying, and the resonator design that makes the most use of this coupling, the resonator exhibited an electromechanical coupling coefficient $k_{mathrm {t}}^{2}$ as high as 5.36%, an unloaded $Q_{mathrm {u,p}}$ of 2916 at the parallel resonant peak of 524.85 MHz and the associated figure of merit (FOM) of 156.0. Ladder filters built upon this design achieved an insertion loss of −3.72 dB and fractional bandwidths of 2.78%/1.8% for the reception (Rx)/transmission (Tx) branch, respectively. The ability to build spurious-free, frequency lithographically defined, and CMOS-compatible resonators and filters will be of great assistance in the realization of next-generation telecommunication systems.[2024-0034]
{"title":"A Comprehensive Approach for Total Suppression of In-Band Spurious Modes in UHF Al0.72Sc0.28N Lamb Wave Resonators and Filters","authors":"Zichen Tang;Giovanni Esteves;Sean Yen;Travis R. Young;Michael David Henry;Loren Gastian;Christopher Nordquist;Roy H. Olsson","doi":"10.1109/JMEMS.2024.3404420","DOIUrl":"10.1109/JMEMS.2024.3404420","url":null,"abstract":"In this paper, spurious mode suppression methods for Al0.72Sc0.28N Lamb wave resonators and filters using the lowest order symmetric (S0) Lamb wave were meticulously studied and exercised. By adopting the method formally known as apodization, which inherently incorporates controlled finger lengths and bus-interdigitated transducer (IDTs) separation, in conjunction with a full-width anchor and an aperture-matched release pit geometry, the complete eradication of spurious mode responses in the resonator passband was demonstrated. Owing to the high piezoelectric coefficient brought by the scandium alloying, and the resonator design that makes the most use of this coupling, the resonator exhibited an electromechanical coupling coefficient \u0000<inline-formula> <tex-math>$k_{mathrm {t}}^{2}$ </tex-math></inline-formula>\u0000 as high as 5.36%, an unloaded \u0000<inline-formula> <tex-math>$Q_{mathrm {u,p}}$ </tex-math></inline-formula>\u0000 of 2916 at the parallel resonant peak of 524.85 MHz and the associated figure of merit (FOM) of 156.0. Ladder filters built upon this design achieved an insertion loss of −3.72 dB and fractional bandwidths of 2.78%/1.8% for the reception (Rx)/transmission (Tx) branch, respectively. The ability to build spurious-free, frequency lithographically defined, and CMOS-compatible resonators and filters will be of great assistance in the realization of next-generation telecommunication systems.[2024-0034]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 4","pages":"456-467"},"PeriodicalIF":2.5,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884709","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}
Pub Date : 2024-06-03DOI: 10.1109/JMEMS.2024.3402279
{"title":"Journal of Microelectromechanical Systems Publication Information","authors":"","doi":"10.1109/JMEMS.2024.3402279","DOIUrl":"https://doi.org/10.1109/JMEMS.2024.3402279","url":null,"abstract":"","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 3","pages":"C2-C2"},"PeriodicalIF":2.7,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10547179","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141245240","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}
The optomechanical uncooled infrared (IR) detector, characterized by a straightforward manufacturing process and sensitivity comparable to photonic detectors, employs bi-material microcantilevers as individual pixels. The detector’s key performance parameters are thermomechanical sensitivity and time constant, which are directly proportional to the coefficient of thermal expansion (CTE) mismatch and thermal mass of the two materials. Carbon nanotubes (CNTs), which exhibit thermal contraction axially, have a CTE value of $- 11 times 10 ^{-6},,text{K}^{-1}$ around room temperature. When combined with metals, such as gold, which have a positive CTE, it is possible to create bi-material pixels with superior thermomechanical sensitivity. The low thermal mass nature of CNTs inherently endows the pixels with a rapid thermal response. To realize an optomechanical IR detector based on super-aligned CNTs, a microfabrication process was developed that incorporates a liquid-induced CNT self-assembled step. Theoretical analyses indicate that the thermomechanical sensitivity and response speed are doubled compared to traditional ceramic-metal based photomechanical uncooled IR detectors. The experimental results are in good agreement with the theoretical values, demonstrating a measured time constant and thermomechanical sensitivity of 62 ms and $0.466~mu text{m}$ /K, respectively. This design offers a viable path towards the development of high-performance uncooled IR detectors, facilitated by the integration of super-aligned CNTs. [2024-0011]
光机械非制冷红外（IR）探测器采用双材料微悬臂作为单个像素，其特点是制造工艺简单，灵敏度可与光子探测器媲美。该探测器的关键性能参数是热机械灵敏度和时间常数，它们与两种材料的热膨胀系数（CTE）失配和热质量成正比。碳纳米管（CNTs）轴向热收缩，在室温下的热膨胀系数值为 $- 11 times 10 ^{-6},text{K}^{-1}$。当与具有正 CTE 的金属（如金）结合时，就有可能制造出具有卓越热机械灵敏度的双材料像素。碳纳米管的低热质量特性赋予了像素快速的热响应。为了实现基于超对齐碳纳米管的光机械红外探测器，我们开发了一种微制造工艺，其中包含液体诱导碳纳米管自组装步骤。理论分析表明，与传统的基于陶瓷金属的光机械非致冷红外探测器相比，热机械灵敏度和响应速度都提高了一倍。实验结果与理论值十分吻合，测量的时间常数和热机械灵敏度分别为 62 ms 和 0.466~mu text{m}$ /K。这种设计为开发高性能非致冷红外探测器提供了一条可行的途径，超对齐碳纳米管的集成为其提供了便利。[2024-0011]
{"title":"High Sensitivity and Rapid Response Optomechanical Uncooled Infrared Detector From Self-Assembled Super-Aligned Carbon Nanotubes Film","authors":"Peng Zhang;Huwang Hou;Zhendong Luo;Ye Feng;Hongmei Zhong;Hui Zhang;Ting Meng;Yang Zhao","doi":"10.1109/JMEMS.2024.3384497","DOIUrl":"10.1109/JMEMS.2024.3384497","url":null,"abstract":"The optomechanical uncooled infrared (IR) detector, characterized by a straightforward manufacturing process and sensitivity comparable to photonic detectors, employs bi-material microcantilevers as individual pixels. The detector’s key performance parameters are thermomechanical sensitivity and time constant, which are directly proportional to the coefficient of thermal expansion (CTE) mismatch and thermal mass of the two materials. Carbon nanotubes (CNTs), which exhibit thermal contraction axially, have a CTE value of \u0000<inline-formula> <tex-math>$- 11 times 10 ^{-6},,text{K}^{-1}$ </tex-math></inline-formula>\u0000 around room temperature. When combined with metals, such as gold, which have a positive CTE, it is possible to create bi-material pixels with superior thermomechanical sensitivity. The low thermal mass nature of CNTs inherently endows the pixels with a rapid thermal response. To realize an optomechanical IR detector based on super-aligned CNTs, a microfabrication process was developed that incorporates a liquid-induced CNT self-assembled step. Theoretical analyses indicate that the thermomechanical sensitivity and response speed are doubled compared to traditional ceramic-metal based photomechanical uncooled IR detectors. The experimental results are in good agreement with the theoretical values, demonstrating a measured time constant and thermomechanical sensitivity of 62 ms and \u0000<inline-formula> <tex-math>$0.466~mu text{m}$ </tex-math></inline-formula>\u0000/K, respectively. This design offers a viable path towards the development of high-performance uncooled IR detectors, facilitated by the integration of super-aligned CNTs. [2024-0011]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 3","pages":"376-383"},"PeriodicalIF":2.7,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140567509","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}
Pub Date : 2024-04-15DOI: 10.1109/JMEMS.2024.3382974
Isha Lodhi;Durga Gajula;Devin K. Brown;Nikolas T. Roeske;David R. Myers;Wilbur A. Lam;Azadeh Ansari;Oliver Brand
Several studies demonstrate that large variations in biologically cell-generated forces are strong indicators of diseases in the body. To realize the full potential of single-cell biomechanical properties as label-free, non-invasive biomarkers in cell-based disease diagnoses, we need high-throughput test platforms that interrogate single cells individually while allowing measurement of thousands of cells at a time. This work presents a piezoresistive sub- $mu text{N}$ lateral force sensing approach using vertical pillars as structural elements and silicon-based, N-type piezoresistors embedded underneath the pillars for stress-sensing. Experimental testing of the first generation of sensors developed shows excellent $text{F}_{mathrm {x}}$ sensing resolution down to $sim $ 70 nN. Measured sensitivities of devices with different pillar geometries range from $Delta text{R}$ /R = 0.05% to 0.14% $mu text{N}^{-1}$ and are varied by simply scaling pillar geometry. While having a comparable resolution to existing MEMS in-plane sensors, the sensor design sets itself apart from existing approaches with its 3D printed pillar-based approach, which is combined with traditional nanofabrication to achieve 500 nm to $3 , mu text{m}$ width, in-substrate piezoresistors. Effective device footprint is a compact few $mu text{m}^{2}$ on substrate which makes the sensor design ideal for implementation in large, dense sensing arrays with $mu text{m}$ -scale sensor-to-sensor pitches in both in-plane axes. [2023-0190]
{"title":"Piezoresistive Micropillar Sensors for Nano-Newton Cell Traction Force Sensing","authors":"Isha Lodhi;Durga Gajula;Devin K. Brown;Nikolas T. Roeske;David R. Myers;Wilbur A. Lam;Azadeh Ansari;Oliver Brand","doi":"10.1109/JMEMS.2024.3382974","DOIUrl":"10.1109/JMEMS.2024.3382974","url":null,"abstract":"Several studies demonstrate that large variations in biologically cell-generated forces are strong indicators of diseases in the body. To realize the full potential of single-cell biomechanical properties as label-free, non-invasive biomarkers in cell-based disease diagnoses, we need high-throughput test platforms that interrogate single cells individually while allowing measurement of thousands of cells at a time. This work presents a piezoresistive sub-\u0000<inline-formula> <tex-math>$mu text{N}$ </tex-math></inline-formula>\u0000 lateral force sensing approach using vertical pillars as structural elements and silicon-based, N-type piezoresistors embedded underneath the pillars for stress-sensing. Experimental testing of the first generation of sensors developed shows excellent \u0000<inline-formula> <tex-math>$text{F}_{mathrm {x}}$ </tex-math></inline-formula>\u0000 sensing resolution down to \u0000<inline-formula> <tex-math>$sim $ </tex-math></inline-formula>\u000070 nN. Measured sensitivities of devices with different pillar geometries range from \u0000<inline-formula> <tex-math>$Delta text{R}$ </tex-math></inline-formula>\u0000/R = 0.05% to 0.14% \u0000<inline-formula> <tex-math>$mu text{N}^{-1}$ </tex-math></inline-formula>\u0000 and are varied by simply scaling pillar geometry. While having a comparable resolution to existing MEMS in-plane sensors, the sensor design sets itself apart from existing approaches with its 3D printed pillar-based approach, which is combined with traditional nanofabrication to achieve 500 nm to \u0000<inline-formula> <tex-math>$3 , mu text{m}$ </tex-math></inline-formula>\u0000 width, in-substrate piezoresistors. Effective device footprint is a compact few \u0000<inline-formula> <tex-math>$mu text{m}^{2}$ </tex-math></inline-formula>\u0000 on substrate which makes the sensor design ideal for implementation in large, dense sensing arrays with \u0000<inline-formula> <tex-math>$mu text{m}$ </tex-math></inline-formula>\u0000-scale sensor-to-sensor pitches in both in-plane axes. [2023-0190]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 3","pages":"395-402"},"PeriodicalIF":2.7,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140567694","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}
In this study, we introduce an innovative approach to vacuum-encapsulation of MEMS resonators using Silicon Migration Seal (SMS) technology, a novel wafer-level vacuum packaging method. SMS utilizes silicon reflow phenomena under high-temperature (>1000°C) hydrogen environments to seal release holes effectively. We successfully demonstrated this technique on a MEMS resonator made on a standard SOI wafer, commonly used in inertial sensors and timing devices. After the encapsulation, hydrogen diffusion from the sealed cavity was performed through annealing at 430°C for 27 hours in a nitrogen environment. Further analysis using focused ion beam (FIB) penetration outside the resonating element confirmed an impressive vacuum level improvement in the sealed cavity, estimated at ~60 Pa. Notably, after additional air-baking at 145°C, the maintained high Q factor suggests a potential vacuum level below 10 Pa. These findings not only illustrate the efficiency of SMS in wafer-level vacuum packaging but also open up possibilities for optimizing sealing pressure in MEMS packaging. [2024-0014]
{"title":"Vacuum-Sealed MEMS Resonators Based on Silicon Migration Sealing and Hydrogen Diffusion","authors":"Tianjiao Gong;Muhammad Jehanzeb Khan;Yukio Suzuki;Takashiro Tsukamoto;Shuji Tanaka","doi":"10.1109/JMEMS.2024.3382768","DOIUrl":"10.1109/JMEMS.2024.3382768","url":null,"abstract":"In this study, we introduce an innovative approach to vacuum-encapsulation of MEMS resonators using Silicon Migration Seal (SMS) technology, a novel wafer-level vacuum packaging method. SMS utilizes silicon reflow phenomena under high-temperature (>1000°C) hydrogen environments to seal release holes effectively. We successfully demonstrated this technique on a MEMS resonator made on a standard SOI wafer, commonly used in inertial sensors and timing devices. After the encapsulation, hydrogen diffusion from the sealed cavity was performed through annealing at 430°C for 27 hours in a nitrogen environment. Further analysis using focused ion beam (FIB) penetration outside the resonating element confirmed an impressive vacuum level improvement in the sealed cavity, estimated at ~60 Pa. Notably, after additional air-baking at 145°C, the maintained high Q factor suggests a potential vacuum level below 10 Pa. These findings not only illustrate the efficiency of SMS in wafer-level vacuum packaging but also open up possibilities for optimizing sealing pressure in MEMS packaging. [2024-0014]","PeriodicalId":16621,"journal":{"name":"Journal of Microelectromechanical Systems","volume":"33 3","pages":"369-375"},"PeriodicalIF":2.7,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10497109","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140567757","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}
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