Piezoelectric-on-Silicon Lateral Bulk Acoustic Wave Micromechanical Resonators
TL;DR: In this article, the design, fabrication, and characterization of piezoelectrically-transduced micromechanical single-crystal-silicon resonators operating in their lateral bulk acoustic modes to address the need for high-Q microelectronic-integrable frequency-selective components is presented.
Abstract: This paper reports on the design, fabrication, and characterization of piezoelectrically-transduced micromechanical single-crystal-silicon resonators operating in their lateral bulk acoustic modes to address the need for high-Q microelectronic-integrable frequency-selective components. A simple electromechanical model for optimizing performance is presented. For verification, resonators were fabricated on 5-mum-thick silicon-on- insulator substrates and use a 0.3-mum zinc oxide film for transduction. A bulk acoustic mode was observed from a 240 mum times 40 mum resonator with a 600-Omega impedance (Q=3400 at P=1 atm) at 90 MHz. A linear resonator absorbed power of -0.5 dBm and an output current of 1.3 mA rms were measured. The same device also exhibited a Q of 12 000 in its fundamental extensional mode at a pressure of 5 torr.
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Northumbria University1, University of Electronic Science and Technology of China2, University of Bolton3, Griffith University4, University of Edinburgh5, University of Cambridge6, University of Manchester7, Technical University of Madrid8, Nanyang Technological University9, Tokyo Institute of Technology10
TL;DR: In this article, the authors acknowledge support from the Innovative electronic manufacturing research centre (IeMRC) through the EPSRC funded flagship project SMART MICROSYSTEMS.
439 citations
TL;DR: This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency reference oscillators, designed and fabricated in 2 classes--high-order and coupled-array and the performance characteristics of the oscillators are measured and discussed.
Abstract: This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency reference oscillators Low-motional impedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array Devices of each class are used to assemble reference oscillators and the performance characteristics of the oscillators are measured and discussed Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient The lowest reported power consumption is ~350 muW for an oscillator operating at ~106 MHz A passive temperature compensation method is also utilized bThis paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency reference oscillators Low-motionalimpedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array Devices of each class are used to assemble reference oscillators and the performance characteristics of the oscillators are measured and discussed Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient The lowest reported power consumption is ~350 muW for an oscillator operating at ~106 MHz A passive temperature compensation method is also utilized by including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-24 ppm/degC) temperature coefficient of frequency is obtained for an 82-MHz oscillatory including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-24 ppm/degC) temperature coefficient of frequency is obtained for an 82-MHz oscillator
206 citations
Cites background from "Piezoelectric-on-Silicon Lateral Bu..."
...The close-to-carrier phase noise of the oscillator is −88 dbc/Hz at 1-kHz offset from the carrier frequency....
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...These resonators are operated at low pressures (mTorr regime), which makes their packaging process costly and challenging. also, the temperature compensation techniques demonstrated so far usually lose efficiency at high frequencies [3]....
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...These devices are fabricated on a 5-μm-thick soI substrate....
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...The motional impedance of a fundamental mode resonator with two electrodes covering the entire top surface [5] is R t E d E WQ 1 31 2 22 » p rtot eff eff f , (2) where ttot is the total thickness of the block, d31 is the transverse piezoelectric coefficient, Ef is the young’s modulus of the…...
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TL;DR: In this paper, the authors review the electromechanical, thermal, acoustic, and piezoelectric properties of GaN and describe the working principle of some of the reported high-performance GaN-based microelectromechanical components.
Abstract: Gallium nitride (GaN) is a wide bandgap semiconductor material and is the most popular material after silicon in the semiconductor industry. The prime movers behind this trend are LEDs, microwave, and more recently, power electronics. New areas of research also include spintronics and nanoribbon transistors, which leverage some of the unique properties of GaN. GaN has electron mobility comparable with silicon, but with a bandgap that is three times larger, making it an excellent candidate for high-power applications and high-temperature operation. The ability to form thin-AlGaN/GaN heterostructures, which exhibit the 2-D electron gas phenomenon leads to high-electron mobility transistors, which exhibit high Johnson's figure of merit. Another interesting direction for GaN research, which is largely unexplored, is GaN-based micromechanical devices or GaN microelectromechanical systems (MEMS). To fully unlock the potential of GaN and realize new advanced all-GaN integrated circuits, it is essential to cointegrate passive devices (such as resonators and filters), sensors (such as temperature and gas sensors), and other more than Moore functional devices with GaN active electronics. Therefore, there is a growing interest in the use of GaN as a mechanical material. This paper reviews the electromechanical, thermal, acoustic, and piezoelectric properties of GaN, and describes the working principle of some of the reported high-performance GaN-based microelectromechanical components. It also provides an outlook for possible research directions in GaN MEMS.
170 citations
TL;DR: A review of the remarkable progress that has been made during the past few decades in design, modeling, and fabrication of micromachined resonators with references to the most influential contributions in the field for those interested in a deeper understanding of the material.
Abstract: This paper is a review of the remarkable progress that has been made during the past few decades in design, modeling, and fabrication of micromachined resonators. Although micro-resonators have come a long way since their early days of development, they are yet to fulfill the rightful vision of their pervasive use across a wide variety of applications. This is partially due to the complexities associated with the physics that limit their performance, the intricacies involved in the processes that are used in their manufacturing, and the trade-offs in using different transduction mechanisms for their implementation. This work is intended to offer a brief introduction to all such details with references to the most influential contributions in the field for those interested in a deeper understanding of the material.
162 citations
Cites background from "Piezoelectric-on-Silicon Lateral Bu..."
...Bulk modes resonators have been reported for beams [55–57], rectangular plates [58,59], square plates [60,61], and circular disks [62,63]....
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TL;DR: In this article, the authors present fabrication, characterization, and modeling of micro/nanoelectromechanical high-frequency resonators actuated using thermal forces with piezoresistive readout.
Abstract: This paper presents fabrication, characterization, and modeling of micro/nanoelectromechanical high-frequency resonators actuated using thermal forces with piezoresistive readout. Thermally actuated single-crystalline silicon resonators with frequencies (up to 61 MHz) have been successfully demonstrated. It is shown both theoretically and experimentally that, as opposed to the general perception, thermal actuation can be a viable actuation mechanism for high-frequency resonators, and using appropriate design guidelines, this actuation mechanism could even be more suitable for higher frequency rather than lower frequency applications. It has been shown through comprehensive thermoelectro-mechanical modeling that thermal-piezoresistive nanomechanical resonators with frequencies in the gigahertz range can exhibit motional conductance values as high as 1 mA/V while consuming static power as low as a few microwatts.
105 citations
References
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01 Jan 1997TL;DR: The second edition of the Fundamentals of Microfabrication as discussed by the authors provides an in-depth coverage of the science of miniaturization, its methods, and materials, from the fundamentals of lithography through bonding and packaging to quantum structures and molecular engineering.
Abstract: MEMS technology and applications have grown at a tremendous pace, while structural dimensions have grown smaller and smaller, reaching down even to the molecular level. With this movement have come new types of applications and rapid advances in the technologies and techniques needed to fabricate the increasingly miniature devices that are literally changing our world.A bestseller in its first edition, Fundamentals of Microfabrication, Second Edition reflects the many developments in methods, materials, and applications that have emerged recently. Renowned author Marc Madou has added exercise sets to each chapter, thus answering the need for a textbook in this field.Fundamentals of Microfabrication, Second Edition offers unique, in-depth coverage of the science of miniaturization, its methods, and materials. From the fundamentals of lithography through bonding and packaging to quantum structures and molecular engineering, it provides the background, tools, and directions you need to confidently choose fabrication methods and materials for a particular miniaturization problem.New in the Second EditionRevised chapters that reflect the many recent advances in the fieldUpdated and enhanced discussions of topics including DNA arrays, microfluidics, micromolding techniques, and nanotechnology In-depth coverage of bio-MEMs, RF-MEMs, high-temperature, and optical MEMs.Many more links to the WebProblem sets in each chapter
2,334 citations
TL;DR: In this article, the authors reviewed the literature in this field, with an emphasis on the factors that impact the magnitude of the available piezoelectric response for non-ferroelectric materials such as ZnO and AlN.
Abstract: Thin film piezoelectric materials offer a number of advantages in microelectromechanical systems (MEMS), due to the large motions that can be generated, often with low hysteresis, the high available energy densities, as well as high sensitivity sensors with wide dynamic ranges, and low power requirements This paper reviews the literature in this field, with an emphasis on the factors that impact the magnitude of the available piezoelectric response For non-ferroelectric piezoelectrics such as ZnO and AlN, the importance of film orientation is discussed The high available electrical resistivity in AlN, its compatibility with CMOS processing, and its high frequency constant make it especially attractive in resonator applications The higher piezoelectric response available in ferroelectric films enables lower voltage operation of actuators, as well as high sensitivity sensors Among ferroelectric films, the majority of the MEMS sensors and actuators developed have utilized lead zirconate titanate (PZT) films as the transducer Randomly oriented PZT films show piezoelectric e(31, f) coefficients of about - 7 C/m(2) at the morphotropic phase boundary In PZT films, orientation, composition, grain size, defect chemistry, and mechanical boundary conditions all impact the observed piezoelectric coefficients The highest achievable piezoelectric responses can be observed in {001} oriented rhombohedrally-distorted perovskites For a variety of such films, e(31,f) coefficients of - 12 to - 27 C/m(2) have been reported
1,016 citations
29 Aug 2005
TL;DR: As vibrating RF MEMS devices are perceived more as circuit building blocks than as stand-alone devices, and as the frequency processing circuits they enable become larger and more complex, the makings of an integrated micromechanical circuit technology begin to take shape, perhaps with a functional breadth not unlike that of integrated transistor circuits.
Abstract: An overview on the vise of microelectromechanical systems (MEMS) technologies for timing and frequency control is presented. In particular, micromechanical RF filters and reference oscillators based on recently demonstrated vibrating on-chip micromechanical resonators with Q's > 10,000 at 1.5 GHz are described as an attractive solution to the increasing count of RF components (e.g., filters) expected to be needed by future multiband, multimode wireless devices. With Q's this high in on-chip abundance, such devices might also enable a paradigm shift in the design of timing and frequency control functions, where the advantages of high-Q are emphasized, rather than suppressed (e.g., due to size and cost reasons), resulting in enhanced robustness and power savings. Indeed, as vibrating RF MEMS devices are perceived more as circuit building blocks than as stand-alone devices, and as the frequency processing circuits they enable become larger and more complex, the makings of an integrated micromechanical circuit technology begin to take shape, perhaps with a functional breadth not unlike that of integrated transistor circuits. With even more aggressive three-dimensional MEMS technologies, even higher on-chip Q's are possible, such as already achieved via chip-scale atomic physics packages, which so far have achieved Q's > 107 using atomic cells measuring only 10 mm3 in volume and consuming just 5 mW of power, all while still allowing atomic clock Allan deviations down to 10-11 at one hour
776 citations
TL;DR: In this article, the authors analyzed the nonlinear effects of single-crystal silicon micro-resonators with the focus on mechanical nonlinearities and showed that the higher energy density attainable with the silicon resonators can partially compensate for the small microresonator size.
Abstract: Nonlinear effects in single-crystal silicon microresonators are analyzed with the focus on mechanical nonlinearities. The bulk acoustic wave (BAW) resonators are shown to have orders-of-magnitude higher energy storage capability than flexural beam resonators. The bifurcation point for the silicon BAW resonators is measured and the maximum vibration amplitude is shown to approach the intrinsic material limit. The importance of nonlinearities in setting the limit for vibration energy storage is demonstrated in oscillator applications. The phase noise calculated for silicon microresonator-based oscillators is compared to the conventional macroscopic quartz-based oscillators, and it is shown that the higher energy density attainable with the silicon resonators can partially compensate for the small microresonator size. Scaling law for microresonator phase noise is developed.
403 citations
"Piezoelectric-on-Silicon Lateral Bu..." refers background in this paper
...Reported ρW,max’s for bulk acoustic wave quartz crystal units and capacitive silicon micromechanical resonators are 190 J/m(3) and 180 kJ/m(3), respectively [10]....
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...SCS has an energy density much greater than that of quartz [10] for good linearity....
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TL;DR: In this article, the development of the thin-film resonator technology and the core elements that give rise to resonators and filters for today's high performance wireless applications are surveyed.
Abstract: Advances in wireless systems have placed increased demands on high performance frequency control devices for operation into the microwave range. With spectrum crowding, high bandwidth requirements, miniaturization, and low cost requirements as a background, the thin film resonator technology has evolved into the mainstream of applications. This technology has been under development for over 40 years in one form or another, but it required significant advances in integrated circuit processing to reach microwave frequencies and practical manufacturing for high-volume applications. This paper will survey the development of the thin film resonator technology and describe the core elements that give rise to resonators and filters for today's high performance wireless applications.
204 citations