Download or read book Dual Mode Thin Film Bulk Acoustic Resonators FBARs Based on AlN ZnO and GaN Films with Tilted C Axis Orientation written by and published by . This book was released on 2010 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin film bulk acoustic wave resonators (FBAR) using piezoelectric AlN, ZnO and GaN thin films have attracted extensive research activities in the past years. Highly c-axis oriented (normal-plane orientation) binary semiconductor piezoelectric thin films are particularly investigated for resonators operating at the fundamental thickness longitudinal mode. Depending on the processing conditions, tilted polarization (c-axis off the normal direction to the substrate surface) is often found in the as-deposited piezoelectric thin films, which leads to the coexistence of thickness longitudinal mode and shear mode for the thin film resonators.

Download or read book Multilayer Integrated Film Bulk Acoustic Resonators written by Yafei Zhang and published by Springer Science & Business Media. This book was released on 2012-08-28 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mulilayer Integrated Film Bulk Acoustic Resonators mainly introduces the theory, design, fabrication technology and application of a recently developed new type of device, multilayer integrated film bulk acoustic resonators, at the micro and nano scale involving microelectronic devices, integrated circuits, optical devices, sensors and actuators, acoustic resonators, micro-nano manufacturing, multilayer integration, device theory and design principles, etc. These devices can work at very high frequencies by using the newly developed theory, design, and fabrication technology of nano and micro devices. Readers in fields of IC, electronic devices, sensors, materials, and films etc. will benefit from this book by learning the detailed fundamentals and potential applications of these advanced devices. Prof. Yafei Zhang is the director of the Ministry of Education’s Key Laboratory for Thin Films and Microfabrication Technology, PRC; Dr. Da Chen was a PhD student in Prof. Yafei Zhang’s research group.

Download or read book Tuneable Film Bulk Acoustic Wave Resonators written by Spartak Gevorgian and published by Springer Science & Business Media. This book was released on 2013-02-14 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: To handle many standards and ever increasing bandwidth requirements, large number of filters and switches are used in transceivers of modern wireless communications systems. It makes the cost, performance, form factor, and power consumption of these systems, including cellular phones, critical issues. At present, the fixed frequency filter banks based on Film Bulk Acoustic Resonators (FBAR) are regarded as one of the most promising technologies to address performance -form factor-cost issues. Even though the FBARs improve the overall performances the complexity of these systems remains high. Attempts are being made to exclude some of the filters by bringing the digital signal processing (including channel selection) as close to the antennas as possible. However handling the increased interference levels is unrealistic for low-cost battery operated radios. Replacing fixed frequency filter banks by one tuneable filter is the most desired and widely considered scenario. As an example, development of the software based cognitive radios is largely hindered by the lack of adequate agile components, first of all tuneable filters. In this sense the electrically switchable and tuneable FBARs are the most promising components to address the complex cost-performance issues in agile microwave transceivers, smart wireless sensor networks etc. Tuneable Film Bulk Acoustic Wave Resonators discusses FBAR need, physics, designs, modelling, fabrication and applications. Tuning of the resonant frequency of the FBARs is considered. Switchable and tuneable FBARs based on electric field induced piezoelectric effect in paraelectric phase ferroelectrics are covered. The resonance of these resonators may be electrically switched on and off and tuned without hysteresis. The book is aimed at microwave and sensor specialists in the industry and graduate students. Readers will learn about principles of operation and possibilities of the switchable and tuneable FBARs, and will be given general guidelines for designing, fabrication and applications of these devices.

Download or read book Acoustic Wave and Electromechanical Resonators written by Humberto Campanella and published by Artech House. This book was released on 2010 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: This groundbreaking book provides you with a comprehensive understanding of FBAR (thin-film bulk acoustic wave resonator), MEMS (microelectomechanical system), and NEMS (nanoelectromechanical system) resonators. For the first time anywhere, you find extensive coverage of these devices at both the technology and application levels. This practical reference offers you guidance in design, fabrication, and characterization of FBARs, MEMS and NEBS. It discusses the integration of these devices with standard CMOS (complementary-metal-oxide-semiconductor) technologies, and their application to sensing and RF systems. Moreover, this one-stop resource looks at the main characteristics, differences, and limitations of FBAR, MEMS, and NEMS devices, helping you to choose the right approaches for your projects. Over 280 illustrations and more than 130 equations support key topics throughout the book.

Download or read book Surface Acoustic Wave Devices Based on C plane and A plane AlScN written by Anli Ding and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The global mobile data volume is projected to grow five-fold by the end of 2025 and transmission rates must keep up. 5G standard promises higher rates by increasing relative bandwidths of the frequency bands used for mobile communications. The relative bandwidth of radio frequency (RF) filters is approximately half of the effective electromechanical coupling of their components, i.e. surface acoustic wave (SAW) and bulk acoustic wave (BAW) resonators. The traditional materials, e.g. aluminum nitride (AlN), are only suitable to a limited extent for the 5G RF filters. Compared to AlN, aluminum scandium nitride (Al1-xScxN with x 0.43) exhibits up to twice as high piezoelectric coefficient e33 and up to two times lower elastic coefficient C33, leading to higher electromechanical coupling, while retaining all the advantages of AlN. Consequently, it is considered a promising material for 5G RF filters.brbrThe potential of AlScN can be evaluated by fabricating SAW resonators based on this novel material and thoroughly investigating their performance. Furthermore, as the electromechanical coupling of SAW resonators based on, e.g. AlN or GaN, can be improved by rotating the "piezoelectric axis" (i.e. polar c-axis) from out-of-plane of the thin film (i.e. c-plane) to in-the-plane (i.e. a-plane), higher coupling can also be expected with a-plane AlScN as the active material. However, so far most AlScN investigations have focused on its c-plane orientation. The aim of this thesis, therefore, is to design and fabricate AlScN-based SAW resonators, investigate their performance with regards to Sc concentration, substrate, temperature, crystal orientation of the thin film (a-plane, c-plane) and SAW propagation direction as well as find their optimal design for high effective electromechanical coupling.brbrIn this work, SAW resonators with x = {0; 0.14; 0.23; 0.32; 0.41} and wavelengths from 2 to 24 μm were fabricated on sputter-deposited c-plane Al1-xScxN/Si(001), c-plane Al1-xScxN/Al2O3(0001) as well as a-plane Al1-xScxN/Al2O3(1-102) thin films and their performance systematically characterized. The resulting resonant frequencies lie in the range of 0.18 to 2.1 GHz. The coupling was found to increase with the amount of resonator fingers and coupling maxima were found according to aperture and the bus-bar length. Compared to the resonators based on AlN, the coupling improved by up to 500 % with x = 0.41. Such an increase was caused mostly by the mentioned evolution of Al1-xScxN material parameters e33 and C33 with x. The C33, in addition to C44 and C11, also influences the resonator frequency, which slightly decreased with x. To the best of the author's knowledge, such a systematic study of SAW resonators based on Al1-xScxN with x = [0; 0.41] has not yet been done. Moreover, only one study has been reported on the performance of SAW resonators based on Al1-xScxN with x so close to the mentioned threshold of 0.43.brbrIt is also the first time, that high quality a-plane AlScN thin films were grown. Up to 1000 % higher coupling was observed for a-plane Al0.77Sc0.23N compared to c-plane Al0.77Sc0.23N-based resonators. This could be caused by the alignment of the interdigitated transducer created electric field lines and the directions along which the piezoelectric effect takes place. Moreover, the coupling of a-plane AlScN-based resonators was observed to be highly influenced by their orientation. The maxima of coupling, at 1200 % higher than minima, were observed at ±30° away from the likely orientation of c-axis. This could be explained by an additional contribution of AlScN material parameters e15 and C44.brbrFurthermore, switching from c-plane to a-plane AlScN also leads to the change of resonator wavelength at which the maximum positive e33 and C33 influence on coupling is observed. The different position of coupling maxima with regards to the wavelength then enables to cover the frequency range from 1.14 to 1.71 GHz with coupling values in the range from 3.7 to 4.1 %. Moreover, this frequency range can be expanded at both ends and higher coupling can be obtained based on the observed tendencies. Even higher frequencies of 2.05 GHz and 2.87 GHz were reached with a coupling of ~2.8 % by employing the 2nd order SAW propagation modes on a-plane and c-plane Al0.68Sc0.32N-based resonators, respectively.brbrThe temporal and thermal stability of the fabricated resonators was investigated. The temperature coefficient of frequency (TCF) of 2 μm wavelength resonators was observed to increase non-linearly but only slightly (6.8 %) with x from 0 to 0.32. The experimentally obtained phase velocity and coupling dispersion curves were used for simulations of the resonators. The obtained results improve the understanding how the thermal behaviour of each material affects the resonator frequency. The design and simulation models of SAW resonators with complex layered structures can be strengthened. For the first time, the intrinsic SAW TCF of Al1-xScxN was determined and will assist in implementing the temperature compensation for the resonators. It is important for nowaday's smartphones with internal temperatures reaching 90 °C. The agreement of the obtained high coupling with state of the art, good thermal and temporal stability of the resonators signify the high robustness of in-house developed AlScN material growth and SAW resonator fabrication technology.br

Download or read book Progress in the Development of Miniature Thin Film BAW Resonator and Filter Technology written by T. W. Grudkowski and published by . This book was released on 1982 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamental mode bulk acoustic wave resonators and filters have been fabricated from ZnO/Si composite thin films prepared by sputter depositing c-axis oriented polycrystalline ZnO onto single crystal silicon. Resonant frequencies of these devices, which are compatible with silicon IC technology, can be readily controlled in the 100 MHz to 1000 MHz range. Development of improved fabrication procedures is described, emphasizing the importance of smooth resonator surfaces and precise control of ZnO sputtering conditions. Chemical etch treatments of the ZnO is shown to markedly reduce spurious resonances. Device modeling theory is described and the good agreement between experimental data and theory is discussed. Filter insertion loss as low as 4.1 dB and bandwidths between 0.5 and 5 percent have been achieved, Q values as high as 2700 were observed, and out of band rejection of 45 dB was realized. (Author.

Download or read book Multilayer Integrated Film Bulk Acoustic Resonators written by Springer and published by . This book was released on 2012-08-29 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical and Biochemical Applications written by Pierre Laszlo and published by Elsevier. This book was released on 2012-12-02 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: NMR of Newly Accessible Nuclei, Volume 1: Chemical and Biochemical Applications is a 10-chapter text that explores the properties, advantages, developments, and chemical and biochemical applications of NMR technique. This book describes first the operation of an NMR spectrometer under its two aspects, namely, the instrumental and the computational aspects. The next chapters are devoted to some of the most important pulse sequences. The discussion then shifts to the various factors determining the position of the observed absorption and those responsible for the various relaxation processes. The last chapters deal with the specific applications of NMR, including in cation salvation, calcium-binding proteins, polyelectrolyte systems, halogens, and antibiotic ionophores. This book is of value to inorganic and analytical chemists, and biophysicists.

Download or read book Aluminum Nitride Thin Film and Composite Bulk Wave Resonators written by K. M. Lakin and published by . This book was released on 1982 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fundamental material and device properties of miniature bulk wave resonators have been investigated for fundamental mode oscillator control and filter applications in the UHF range. The properties of aluminum nitride in the composite resonator geometry and in an edge-only supported plate configuration are reported. The AlN films were grown in a DC planar magnetron sputtering system using the plasma reaction between sputtered Al from the target and N2 in the plasma. The general sputtering conditions were as follows: substrate temperature equal 200 C, atmospheric gas equal 99.999% Nitrogen, sputtering pressure: 1 x 10 to the minus third power torr, DC power equal 225 watts and deposition rate equal 1.2 micrometer/hr. The films were evaluated by SEM, x-ray diffraction, and Auger electron spectroscopy. These results showed that the sputtered AlN films have a highly oriented structure with the c-axis normal to the surface of the Si substrate.

Download or read book Film Bulk Acoustic Resonators of High Quality Factors in Liquid Environments for Biosensing Applications written by Wencheng Xu and published by . This book was released on 2011 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micro-electro-mechanical systems (MEMS) film bulk acoustic resonator (FBAR) demonstrates label-free biosensing capabilities and is considered to be a promising alternative of quartz crystal microbalance (QCM). FBARs achieve great success in vacuum, or in the air, but find limited applications in liquid media because squeeze damping significantly degrades quality factor (Q) and results in poor frequency resolution. A transmission-line model shows that by confining the liquid in a thickness comparable to the acoustic wavelength of the resonator, Q can be considerably improved. The devices exhibit damped oscillatory patterns of Q as the liquid thickness varies. Q assumes its maxima and minima when the channel thickness is an odd and even multiple of the quarter-wavelength of the resonance, respectively. Microfluidic channels are integrated with longitudinal-mode FBARs (L-FBARs) to realize this design; a tenfold improvement of Q over fully-immersed devices is experimentally verified. Microfluidic integrated FBAR sensors have been demonstrated for detecting protein binding in liquid and monitoring the Vroman effect (the competitive protein adsorption behavior), showing their potential as a promising bio-analytical tool. A contour-mode FBAR (C-FBAR) is developed to further improve Q and to alleviate the need for complex integration of microfluidic channels. The C-FBAR consists of a suspended piezoelectric ring made of aluminum nitride and is excited in the fundamental radial-extensional mode. By replacing the squeeze damping with shear damping, high Qs (189 in water and 77 in human whole blood) are obtained in semi-infinite depth liquids. The C-FBAR sensors are characterized by aptamer - thrombin binding pairs and aqueous glycerine solutions for mass and viscosity sensing schemes, respectively. The C-FBAR sensor demonstrates accurate viscosity measurement from 1 to 10 centipoise, and can be deployed to monitor in-vitro blood coagulation processes in real time. Results show that its resonant frequency decreases as the viscosity of the blood increases during the fibrin generation process after the coagulation cascade. The coagulation time and the start/end of the fibrin generation are quantitatively determined, showing the C-FBAR can be a low-cost, portable yet reliable tool for hemostasis diagnostics.

Download or read book Multilayer Integrated Film Bulk Acoustic Resonators written by Yafei Zhang and published by . This book was released on 2013 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulation and Fabrication of Thin Film Bulk Acoustic Wave Resonator Project Supported by the National Natural Science Foundation of China Nos 61274119 61306141 61335008 and the Natural Science Foundation of Jiangsu Province No BK20131099 written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In this paper, we present the simulation and fabrication of a thin film bulk acoustic resonator (FBAR). In order to improve the accuracy of simulation, an improved Mason model was introduced to design the resonator by taking the coupling effect between electrode and substrate into consideration. The resonators were fabricated by the eight inch CMOS process, and the measurements show that the improved Mason model is more accurate than a simple Mason model. The Q s ( Q at series resonance), Q p ( Q at parallel resonance), Q max and k t 2 of the FBAR were measured to be 695, 814, 1049, and 7.01% respectively, showing better performance than previous reports.

Download or read book Thin film Bulk Acoustic Wave Resonators FBAR written by Humberto Campanella Pineda and published by . This book was released on 2008 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design Fabrication and Characterization of Beam Supported Aluminum Nitride Thin Film Bulk Acoustic Resonators written by Lori Ann Callaghan and published by . This book was released on 2005 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micro-mechanical filters comprised of bulk acoustic resonators are being fabricated and studied as a solution to the demands for low power consumption, high functionality devices in the telecommunication industry. A novel, suspended thin Film Bulk Acoustic wave Resonator (SFBAR) has been fabricated using an aluminum nitride film sputtered directly on a 100 silicon substrate. The suspended membrane design uses thin beams to support, as well as electrically connect, the resonator. The SFBAR has been fabricated by combining both thin film processing and bulk silicon micro machining. The AlN was etched in an Inductively Coupled Plasma (ICP) chlorine etch, using titanium dioxide as the masking material. A silicon Deep Reactive Ion Etch (DRIE) was used to create an open ended air cavity with a novel circular shape. A representative resonator, designated here as sample W9HS8 resonator 10018, was characterized with a Quality Factor values at resonance and anti-resonance of 68 and 151,

Download or read book Fabrication Development and Analysis of Film Bulk Acoustic Resonators on Flexible Polymer Substrates written by Ghazal Hakemi and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is the focus of this project to explore the possibility of achieving Radio Fre?quency (RF) micro-devices on flexible polymer substrates. To this end standard MEMS fabrication methods have been tailored to allow the integration of func?tional materials and device patterning for production of RF MEMS devices with flexible organic substrates. Material quality, device yield, performance and re-liability are critical aspects of our study. The project encompasses the use of a direct integration method for the creation of Film Bulk Acoustic Resonators (FBARs) on Liquid Crystal Polymer (LCP) substrates. An FBAR is a passive component used for resonance and filtering purposes. Its production on organic substrates would lead to a number of ad-vantages including: overall cost savings, size reduction and ability of the device to be directly integrated on the printed circuit board (PCB) front-end with the other essential components (i.e. antenna) without the use of wiring and inter-connections. New fabrication process flows have been developed to allow the creation of FBAR microwave devices on LCP. First of all pre-processing of the polymer substrate is carried out to make it rigid and smooth. Substrate smoothness and stiffness are necessary in order to obtain functioning devices and for the substrate to comply to the standard fabrication methods. Rigidity is achieved through a backing method whereby silicon or glass are attached to LCP with an intermediate adhesive layer. The best way to achieve smoothness was found to be Chemical Mechanical Polishing (CMP). Standard fabrication techniques were then employed to deposit the metal and piezoelectric material and pattern them. Both bulk and surface micromachining were used and, in some cases, tailored to suit the new substrates (LCP) tolerance limits (such as temperature and flexibility). Zinc Oxide (ZnO) piezoelectric is the preferred functional material and it is chosen due to its relatively low deposition temperature re?quirements (below 300C) and its high frequency characteristics. The creation of a front-to-back processed FBAR on LCP is successfully carried out at relatively low temperatures since the Zinc oxide (ZnO) functional mate?rial is proven to yield good crystallinity at a deposition temperature of 100C and also because micromachining temperatures do not generally exceed 115C. The final device is characterized through RF measurements, compared with sim?ulations and standard FBARs and the polymer/ceramic integration reliability for device creation is briefly addressed. In conclusion FBARs are successfully created on LCP with only minor compli?cations related to LCP surface roughness and RIE etch of the polymer. The project lays promising prospects for RF MEMS devices on compliant organic substrates.

Download or read book Quantitative Determination of Lateral Mode Dispersion in Film Bulk Acoustic Resonators Through Laser Acoustic Imaging written by John D. Larson III. and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Film Bulk Acoustic Resonators are useful for many signal processing applications. Detailed knowledge of their operation properties are needed to optimize their design for specific applications. The finite size of these resonators precludes their use in single acoustic modes; rather, multiple wave modes, such as, lateral wave modes are always excited concurrently. In order to determine the contributions of these modes, we have been using a newly developed full-field laser acoustic imaging approach to directly measure their amplitude and phase throughout the resonator. This paper describes new results comparing modeling of both elastic and piezoelectric effects in the active material with imaging measurement of all excited modes. Fourier transformation of the acoustic amplitude and phase displacement images provides a quantitative determination of excited mode amplitude and wavenumber at any frequency. Images combined at several frequencies form a direct visualization of lateral mode excitation and dispersion for the device under test allowing mode identification and comparison with predicted operational properties. Discussion and analysis are presented for modes near the first longitudinal thickness resonance (~900 MHz) in an AlN thin film resonator. Plate wave modeling, taking account of material crystalline orientation, elastic and piezoelectric properties and overlayer metallic films, will be discussed in relation to direct image measurements.

Download or read book Temperature Compensated and High Q Piezoelectric Aluminum Nitride Lamb Wave Resonators for Timing and Frequency Control Applications written by Chih-Ming Lin and published by . This book was released on 2013 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: The explosive development of wireless and mobile communication systems has lead to rapid technology innovation in component performance, complementary metal-oxide semiconductor (CMOS) compatible fabrication techniques, and system improvement to satisfy requirements for faster signal processing, cost efficiency, chip miniaturization, and low power consumption. The demands for the high-performance communication systems whose fundamentals are precise timing and frequency control have driven the current research interests to develop advanced reference oscillators and radio frequency (RF) bandpass filters. In turn a promising microelectromechanical systems (MEMS) resonator technology is required to achieve the ultimate goal. That is, micromechanical vibrating resonators with high quality factor (Q) and good frequency-temperature stability at high series resonance frequency (fs) are the required fundamental components for a high-performance wireless communication system. Recently, Lamb wave mode propagating in piezoelectric thin plates has attracted great attention for designs of the electroacoustic resonators since it combines the advantages of bulk acoustic wave (BAW) and surface acoustic wave (SAW): high phase velocity and multiple frequency excitation by an interdigital transducer (IDT). More specifically, the Lamb wave resonator (LWR) based on an aluminum nitride (AlN) thin film has attracted many attentions because it can offer the high resonance frequency, small temperature-induced frequency drift, low motional resistance, and CMOS compatibility. The lowest-order symmetric (S0) Lamb wave mode propagation in the AlN thin plate is particularly preferred because it exhibits a phase velocity close to 10,000 m/s, a low dispersive phase velocity characteristic, and a moderate electromechanical coupling coefficient. However, the uncompensated AlN LWR shows a first-order temperature coefficient of frequency (TCF) of approximately -25 ppm/C. This level of the temperature stability is unsuitable for any timing application. In addition, the Q of the AlN LWR is degraded to several hundred while the IDT finger width is downscaled to a nanometer scale to raise the resonance frequency up to a few GHz. This dissertation presents comprehensive analytical and experimental results on a new class of temperature-compensated and high-Q piezoelectric AlN LWRs. The temperature compensation of the AlN LWR using the S0 Lamb wave mode is achieved by adding a layer of silicon dioxide (SiO2) with an appropriate thickness ratio to the AlN thin film, and the AlN/SiO2 LWRs can achieve a low first-order TCF at room temperature. Based on the multilayer plate composed of a 1-um-thick AlN film and a 0.83-um-thick SiO2 layer, a temperature-compensated LWR operating at a series resonance frequency of 711 MHz exhibits a zero first-order TCF and a small second-order TCF of -21.5 ppb/C^2 at its turnover temperature, 18.05 C. The temperature dependence of fractional frequency variation is less than 250 parts per million (ppm) over a wide temperature range from -55 to 125 C. In addition to the temperature compensation at room temperature, the thermal compensation of the AlN LWRs is experimentally demonstrated at high temperatures. By varying the normalized AlN and SiO2 thicknesses to the wavelength, the turnover temperature can be designed at high temperatures and the AlN LWRs are temperature-compensated at 214, 430, and 542 C, respectively. The temperature-compensated AlN/SiO2 LWRs are promising for a lot of applications including thermally stable oscillators, bandpass filters, and sensors at room temperature as well as high temperatures. The influences of the bottom electrode upon the characteristics of the LWRs utilizing the S0 Lamb wave mode in the AlN thin plate are theoretically and experimentally studied. Employment of a floating bottom electrode for the LWR reduces the static capacitance in the AlN membrane and accordingly enhances the effective coupling coefficient. The floating bottom electrode simultaneously offers a large coupling coefficient and a simple fabrication process than the grounded bottom electrode but the transduction efficiency is not sacrificed. In contrast to those with the bottom electrode, an AlN LWR with no bottom electrode shows a high Q of around 3,000 since it gets rid of the electrical loss in the metal-to-resonator interface. In addition, it exhibits better power handling capacity than those with the bottom electrode since less thermal nonlinearity induced by the self-heating exists in the resonators. In order to boost the Q, a new class of the AlN LWRs using suspended convex edges is introduced in this dissertation for the first time. The suspended convex edges can efficiently reflect the Lamb waves back towards the transducer as well as confine the mechanical energy in the resonant body. Accordingly the mechanical energy dissipation through the support tethers is significantly minimized and the Q can be markedly enhanced. More specifically, the measured frequency response of a 491.8-MHz LWR with suspended biconvex edges yields a Q of 3,280 which represents a 2.6x enhancement in Q over a 517.9-MHz LWR based on the same AlN thin plate but with the suspended flat edges. The suspended convex edges can efficiently confine mechanical energy in the LWR and reduce the energy dissipation through the support tethers without increasing the motional impedance of the resonator. In addition, the radius of curvature of the suspended convex edges and the AlN thickness normalized to the wavelength can be further optimized to simultaneously obtain high Q, low motional impedance, and large effective coupling coefficient. To further enhance the Q of the LWR, a composite plate including an AlN thin film and an epitaxial cubic silicon carbide (3C-SiC) layer is introduced to enable high-Q and high-frequency micromechanical resonators utilizing high-order Lamb wave modes. The use of the epitaxial 3C-SiC layer is attractive as SiC crystals have been theoretically proven to have an exceptionally large fs and Q product due to its low acoustic loss characteristic at microwave frequencies. In addition, AlN and 3C-SiC have well-matched mechanical and electrical properties, making them a suitable material stack for the electroacoustic resonators. The epitaxial 3C-SiC layer not only provides the micromechanical resonators with a low acoustic loss layer to boost their Q but also enhances the electromechanical coupling coefficients of some high-order Lamb waves in the AlN/3C-SiC composite plate. A micromachined electroacoustic resonator utilizing the third quasi-symmetric (QS3) Lamb wave mode in the AlN/3C-SiC composite plate exhibits a Q of 5,510 at 2.92 GHz, resulting in the highest fs and Q product, 1.61x10^13 Hz, among suspended piezoelectric thin film resonators to date.