Cantilever sensor with stress-concentrating piezoresistor design

Naeli, Kianoush; Brand, Oliver

doi:10.1109/icsens.2005.1597768

Cited by 8 publications

(5 citation statements)

References 6 publications

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“…This goal is achieved by introducing stress concentration region (SCR) in the sensor silicon carrier. This concept was explored by a few researchers to enhance the sensitivity of cantilever sensors [35][36][37][38][39][40][41][42][43]; however, it has not been employed in sensing chips such as strain/stress gauges. This paper explores the possibility of optimizing the dimensions of geometric SCRs to yield a maximum output signal.…”

Section: Introductionmentioning

confidence: 99%

Optimization of geometric characteristics to improve sensing performance of MEMS piezoresistive strain sensors

Mohammed

Moussa

Lou

2009

J. Micromech. Microeng.

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In this paper, the design of MEMS piezoresistive strain sensor is described. ANSYS R , finite element analysis (FEA) software, was used as a tool to model the performance of the silicon-based sensor. The incorporation of stress concentration regions (SCRs), to localize stresses, was explored in detail. This methodology employs the structural design of the sensor silicon carrier. Therefore, the induced strain in the sensing chip yielded stress concentration in the vicinity of the SCRs. Hence, this concept was proved to enhance the sensor sensitivity. Another advantage of the SCRs is to reduce the sensor transverse gauge factor, which offered a great opportunity to develop a MEMS sensor with minimal cross sensitivity. Two basic SCR designs were studied. The depth of the SCRs was also investigated. Moreover, FEA simulation is utilized to investigate the effect of the sensing element depth on the sensor sensitivity. Simulation results showed that the sensor sensitivity is independent of the piezoresistors' depth. The microfabrication process flow was introduced to prototype the different sensor designs. The experiments covered operating temperature range from −50 • C to +50 • C. Finally, packaging scheme and bonding adhesive selection were discussed. The experimental results showed good agreement with the FEA simulation results. The findings of this study confirmed the feasibility of introducing SCRs in the sensor silicon carrier to improve the sensor sensitivity while using relatively high doping levels (5 × 10 19 atoms cm −3 ). The fabricated sensors have a gauge factor about three to four times higher compared to conventional thin-foil strain gauges.

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Section: Introductionmentioning

confidence: 99%

Optimization of geometric characteristics to improve sensing performance of MEMS piezoresistive strain sensors

Mohammed

Moussa

Lou

2009

J. Micromech. Microeng.

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“…This Q value of nanostructured quartz‐based cantilevers is of the same order of magnitude as the mechanical Q of similar and standard non‐piezoelectric silicon cantilevers which typically range from 50 to 1000, but can in some cases be as high as 10 000. [ 20 ] As a result, the epitaxial growth of (100)quartz layer on silicon might not affect the final mechanical Q value of the MEMS structure, probably due to the coherent quartz/silicon interface. Notice that this Q value depends on the external and internal damping phenomena, i.e., the cantilever geometry and the damping caused by viscous and other forces coming from the surrounding media.…”

Section: Structural and Electromechanical Characterization Of Nanostrmentioning

confidence: 99%

Soft‐Chemistry‐Assisted On‐Chip Integration of Nanostructured α‐Quartz Microelectromechanical System

Jolly

Gómez

Sanchez-Fuentes

et al. 2021

Adv Materials Technologies

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The development of advanced piezoelectric α‐quartz microelectromechanical system (MEMS) for sensing and precise frequency control applications requires the nanostructuration and on‐chip integration of this material on silicon material. However, the current quartz manufacturing methods are based on bonding bulk micromachined crystals on silicon, which limits the size, the performance, the integration cost, and the scalability of quartz microdevices. Here, chemical solution deposition, soft‐nanoimprint lithography, and top‐down microfabrication processes are combined to develop the first nanostructured epitaxial (100)α‐quartz/(100)Si piezoelectric cantilevers. The coherent Si/quartz interface and film thinness combined with a controlled nanostructuration on silicon–insulator–silicon technology substrates provide high force and mass sensitivity while preserving the mechanical quality factor of the microelectromechanical systems. This work proves that biocompatible nanostructured epitaxial piezoelectric α‐quartz‐based MEMS on silicon can be engineered at low cost by combining soft‐chemistry and top‐down lithographic techniques.

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“…The piezoresistive areas are defined by boron diffusion with a final doping concentration of 10 19 cm -3 . The general procedure for fabrication of the cantilevers is same as in [9].…”

Section: Fabricationmentioning

confidence: 99%

“…In this work, cantilevers based on such a stressconcentration principle [9] have been designed, fabricated and tested (see Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Coupling High Force Sensitivity and High Stiffness in Piezoresistive Cantilevers with Embedded Si-Nanowires

Naeli

Brand

2007

2007 IEEE Sensors

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Using a single-mask add-on process module, two usually non-coexistent properties of cantilevers, large stiffness and large force sensitivity, are summoned in a single device. To achieve this, a stress-concentrating (SC) principle is used: instead of decreasing the cantilever thickness, which is the conventional approach in increasing its force sensitivity, the stress is locally concentrated in piezoresistive beams or wires. Hence, with a negligible decrease in stiffness, a higher sensitivity is obtained. Results of finite element simulations and experimental data confirm the feasibility of the proposed design. Fabricated cantilevers with implemented stressconcentrating silicon nanowires show a more than 5-fold improvement in force sensitivity compared to a conventional cantilever with the same dimensions, while maintaining the same stiffness. With thinner wires, the sensitivity increases 8-fold at the expense of a 15% decrease in stiffness.

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Cantilever sensor with stress-concentrating piezoresistor design

Cited by 8 publications

References 6 publications

Optimization of geometric characteristics to improve sensing performance of MEMS piezoresistive strain sensors

Optimization of geometric characteristics to improve sensing performance of MEMS piezoresistive strain sensors

Soft‐Chemistry‐Assisted On‐Chip Integration of Nanostructured α‐Quartz Microelectromechanical System

Coupling High Force Sensitivity and High Stiffness in Piezoresistive Cantilevers with Embedded Si-Nanowires

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