Thermally compensated aluminum nitride Lamb wave resonators for high temperature applications

Frequency tuning of aluminum nitride (AlN) microresonators has been demonstrated via localized heating (ovenization) of the resonator. Specifically, piezoelectrically driven ∼100 MHz microresonators were heated by embedded joule heaters in vacuum. Three different designs with three different film stacks were tested, and among the tested devices, thermal resistances as large as 92 K/mW have been demonstrated, which corresponds to 1-mW power consumption to yield a temperature increase of 92 • C. To minimize heat loss, the devices were suspended from the substrate by high thermal isolation beam-type supports. The beams exhibit very high thermal resistance not only due to their high length to cross-sectional area ratio but also because they are made of thin-film-deposited polycrystalline aluminum nitride. Film-deposited AlN has been shown to have thermal conductivity much lower than that measured in bulk materials. Thermal time constants for these devices were measured ranging from submilliseconds to 10 ms depending on the design and film stacks, and frequency tunability was measured as high as 2548 parts per million/mW. The availability of a power-efficient frequency tuning method, coupled with all other performance benefits, makes AlN microresonators a promising candidate for the next-generation timing devices and tunable filters for multiband communication systems.[2012-0035]

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“…The thicker the oxide film (see Stack 3), the smaller the predicted T Cf. Similar analysis was conducted in other works as well [21].…”

Section: ) Resonant Frequency and Temperature Dependencesupporting

confidence: 54%

Oven-Based Thermally Tunable Aluminum Nitride Microresonators

Kim

Nguyen

Wojciechowski

et al. 2013

J. Microelectromech. Syst.

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“…Among various micro-electro-mechanical resonator technologies, aluminum nitride (AlN) Lamb wave resonators utilizing the lowest symmetric (S 0 ) mode have demonstrated the most promising technology for ultimately realizing this vision. [1][2][3][4][5] Recently, the robust temperature compensation of AlN Lamb wave resonators by using one layer of silicon dioxide [6][7][8] or highly doped silicon (Si) 9 has been demonstrated.…”

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confidence: 99%

High-Q aluminum nitride Lamb wave resonators with biconvex edges

Lin

Lai

Hsu

et al. 2011

Applied Physics Letters

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A Lamb wave resonator utilizing an aluminum nitride (AlN) plate with biconvex edges to enhance the quality factor (Q) is demonstrated. The simulation results based on finite element analysis verify that the use of the biconvex edges, instead of the conventional flat edges, can efficiently confine mechanical energy in the AlN Lamb wave resonator. Specifically, the measured frequency response of a 491.8-MHz AlN Lamb wave resonator with biconvex edges yields a Q of 3280 which represents a 2.6× enhancement in Q over a 517.9-MHz Lamb wave resonator on the same AlN plate but with the suspended flat edges.

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“…In addition, several studies have proved that the material properties of multilayer plates can improve the resonator performances remarkably [12][13][14][15][16][17][18]. For example, the Q's of piezoelectric thin film resonators were significantly enhanced using a substrate layer with low acoustic losses, such as single crystal silicon (Si) [12,13].…”

Section: Introductionmentioning

confidence: 99%

Dispersion characteristics of high-order lamb wave modes in an AlN/3C-SiC layered plate

Lin

Chen

Felmetsger³

et al. 2012

2012 IEEE International Ultrasonics Symposium

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A new propagation layered media composed of a piezoelectric thin film and a substrate plate is studied in this work. The displacement profiles, phase velocities, and electromechanical coupling coefficients of Lamb wave modes are theoretically investigated for the c-axis oriented AlN films on cubic silicon carbide (3C-SiC) plates. Due to the different material properties of the AlN and 3C-SiC layers, the displacement profiles of Lamb wave modes are not simply antisymmetric or symmetric with respect to the neutral axis. According to the displacement profiles, the plate acoustic wave modes in the layered plate are classified as quasi-Lamb wave modes. Some high-order quasi-Lamb wave modes in the layered plate have larger electromechanical couplings than the corresponding Lamb wave modes in an AlN thin plate. In addition, the third quasi-symmetric (QS 3 ) Lamb wave mode exhibits a low motional impedance (R m ) of 91 ohm and a high quality factor (Q) up to 5510 at a frequency (f s ) of 2.92 GHz, resulting in the highest f s ·Q product, 1.61×10 13 Hz, among suspended piezoelectric thin film resonators reported to date.Index Terms-Lamb wave resonator, aluminum nitride, cubic silicon carbide, quasi-Lamb wave mode, high quality factor, dispersion, high-order Lamb wave modes, quasi-antisymmetric mode, quasi-symmetric mode, harsh environment.

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Thermally compensated aluminum nitride Lamb wave resonators for high temperature applications

Cited by 113 publications

References 13 publications

Oven-Based Thermally Tunable Aluminum Nitride Microresonators

Oven-Based Thermally Tunable Aluminum Nitride Microresonators

High-Q aluminum nitride Lamb wave resonators with biconvex edges

Dispersion characteristics of high-order lamb wave modes in an AlN/3C-SiC layered plate

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