Faculty Publications
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Item Analysis of Suspension Beams for MEMS Accelerometers: The Effect of Geometric Parameters on the Sensitivity(Institute of Electrical and Electronics Engineers Inc., 2024) Manvi, M.; Mruthyunjaya Swamy, K.B.MEMS accelerometers have revolutionized accelerometer technology with their compact size, low power consumption and improved precision, making them suitable for measuring the motion and vibration. MEMS accelerometers rely on the movement of springs or beams with attached proof mass to detect acceleration. One important factor that impacts how well these accelerometers detect and measure acceleration is their sensitivity. To explore and improve the sensitivity of MEMS accelerometers, the present work focuses on assessing several beam topologies with various cross-sectional forms, such as triangles, slanted squares, circles, and squares using COMSOL Multiphysics software. Triangular beams made of solid material demonstrated the highest sensitivity (15.68 nm/g), but hollow slanted squares exhibited notable sensitivity (148 nm/g). These results highlight how important the beam configuration and geometric parameters are in determining MEMS accelerometer sensitivity. Understanding this relationship helps researchers refine the design of MEMS accelerometers, leading to improved performance and accuracy in motion and vibration related measurements. © 2024 IEEE.Item Microelectronic materials, microfabrication processes, micromechanical structural configuration based stiffness evaluation in MEMS: A review(Elsevier B.V., 2022) Manvi, M.; Mruthyunjaya Swamy, K.B.Microsystem or micro-electro-mechanical system (MEMS) is a revolutionary enabling technology, that is responsible for many of the technological advancements over the past few decades. Many such microsystems consist of suspensions mostly in the form of microcantilevers which are intended to perform desired function by detecting the changes in cantilever bending or vibrational frequency. The bending or deflection of the cantilever beam critically depends upon the mechanical properties, like stiffness, which is contingent on the type of materials, fabrication processes, and structural configurations. This paper evaluates cantilever stiffness of different MEMS devices in relation to aforesaid aspects. Common microelectronic materials like silicon, silicon dioxide, silicon nitride, gold, polymers etc. were seen to provide stiffness ranging from 0.012 N/m to 319.74 N/m that is influenced by elastic modulus & density for a given design. Likewise, fabrication process was seen to affect stiffness through process temperature & residual stress effects for different materials. Also, the structural shape geometry was observed to influence the same due to modified cross-sectional areas and straight & folded spring configurations. In this review, light is shed on abovementioned parameters which are found to be crucial in designing efficient MEMS devices and structures. © 2022 Elsevier B.V.Item Comprehensive simulation study on AlN, ZnO, and PZT-5H piezoelectric materials for microcantilever-based MEMS energy harvesters: Mechanical and electrical insights(SAGE Publications Ltd, 2024) Manvi, M.; Swamy, K.B.M.The piezoelectric effect involves the generation of electric charge in specific materials when subjected to mechanical stress or strain. This phenomenon is utilized in applications such as sensors, actuators, and energy harvesters. Microelectromechanical systems (MEMS) based piezoelectric energy harvesters are especially useful for powering microelectronic devices and sensors, reducing dependency on batteries in situations where regular battery maintenance and/or replacement is either difficult or impractical. While individual piezoelectric materials like aluminum nitride (AlN), zinc oxide (ZnO) and lead zirconate titanate (PZT) have been extensively studied, comparative analyses within a single context are important for designers, but seldom reported. Accordingly, this article presents a comprehensive study on MEMS energy harvesters, focusing on well-known materials like AlN, ZnO, and PZT-5H. Using finite element method based COMSOL Multiphysics software tool, the proposed energy harvesters are simulated and analyzed for their mechanical and electrical properties to evaluate the performance for typical applications. The resonant frequencies for AlN, ZnO, and PZT-5H harvesters are identified at 3300, 2900, and 2800 Hz, respectively, with corresponding power outputs of about 1.28, 190.5, and 0.004 nW under a “1 g” acceleration. This precise evaluation facilitates designers on informed material selection based on performance metrics, enhancing MEMS energy harvester development. Notably, the significantly higher power output for ZnO compared to AlN and PZT-5H challenges conventional material preferences and offers new possibilities for efficient energy harvesting solutions. © IMechE 2024.Item Evaluating the efficacy of lead-free piezoelectric materials in microcantilever based vibration energy harvesters(Institute of Physics, 2024) Manvi, M.; Swamy, M.S.The piezoelectric materials have been extensively utilized in various applications, such as sensors, actuators, and energy harvesters. This study evaluates the performance of six lead-free piezoelectric materials- aluminium nitride (AlN), barium titanate (BaTiO3), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), polyvinylidene fluoride (PVDF), and zinc oxide (ZnO) in MEMS-based piezoelectric vibration energy harvesters (PVEHs) using cantilever configurations. Finite element analysis via COMSOL Multiphysics was employed to assess the deflection, voltage, and power outputs of these materials at their resonance frequencies, both with and without proof masses. The results indicate that BaTiO3 and PVDF cantilevers exhibited the highest voltage outputs, reaching 207.14 mV and 202.07 mV, respectively, with AlN also showing comparable performance at 184.72 mV. ZnO-based cantilevers demonstrated the highest power output of 1.35 nW without proof masses and 190.5 nW with proof masses, indicating its potential for high-power applications. The addition of proof masses generally reduced resonant frequencies but enhanced power outputs, like for ZnO. This comprehensive analysis underscores the critical impact of material selection and structural modifications on the efficiency of PVEHs, with BaTiO3, PVDF, and ZnO emerging as the most promising candidates for optimizing energy harvesting devices. This research lays a foundation for further advancements in piezoelectric MEMS technology, aiming for more efficient energy harvesting solutions. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.