Capacitive Lamé Mode Resonators in $65\ \mu \mathrm{m}$-Thick Monocrystalline Silicon Carbide with Q-Factors Exceeding 20 Million

Yang, Jeremy; Hamelin, Benoit; Ayazi, Farrokh

doi:10.1109/mems46641.2020.9056301

Cited by 13 publications

(11 citation statements)

References 6 publications

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“…In this work, the side-supported Lamé resonator requires only in-plane decoupling; the tethers are augmented with square-shaped unit cells of critical dimension on the order of the quarter wavelength (λ/4) of the shear Lamé wave [10]. A similar phononic crystal has been implemented in nearly Akhiezer-limited silicon resonators making this design an excellent candidate for this work [38].…”

Section: B Pnc: Anchor Loss Mitigation Spurious Mode Suppressionmentioning

confidence: 99%

“…Fabrication of devices follows the process as detailed in [10]. SiCOI substrates with 65 μm n-type 4H-SiC device layer on a 380 μm Si handle layer separated by a thermally-grown silicon dioxide interlayer were custom-made in a process slightly modified from [17].…”

Section: Fabricationmentioning

confidence: 99%

“…Beyond its exceptional material properties that confer robustness in harsh environments, monocrystalline silicon carbide resonators have recently demonstrated mechanical f • Q products beyond 1 × 10 14 in the Akhiezer regime [10] and 1 × 10 17 in the Landau-Rumer regime [11], far beyond the limit of single crystal silicon. Ultra-high mechanical Q-factors combined with a large band gap render 4H-SiC interesting in the pursuit of acoustic control of solid-state defects [12] and high-precision MEMS devices.…”

Section: Introductionmentioning

confidence: 99%

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Investigating Elastic Anisotropy of 4H-SiC Using Ultra-High Q Bulk Acoustic Wave Resonators

Yang

Hamelin

Ayazi

2020

J. Microelectromech. Syst.

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Hexagonal 4H-silicon carbide (4H-SiC) is a transversely isotropic substrate garnering interest for precision MEMS devices such as resonant gyroscopes. This paper investigates the elastic anisotropy of 4H-SiC by utilizing capacitive bulk acoustic wave (BAW) resonators with ultra-high mechanical quality factors ( Q) enabled by phononic crystals. We directly measure the value of C 66 using Lamé mode resonators for the first time and numerically fit the values of C 11 and C 12 using BAW elliptical modes in center-supported solid disk resonators. We compare (0 0 0 1) 4H-SiC to (1 1 1) Si, another in-plane isotropic material and validate (0 0 0 1) 4H-SiC's superior robustness to fabrication and design variations. Measurement of in-plane BAW elliptical modes in multiple disk resonators with as-born frequency splits as low as 3 ppm reveal (0 0 0 1) 4H-SiC's transverse isotropy across process corners. Lamé mode resonators display a temperature coefficient of frequency (TCF) three times lower compared to its Si counterpart. Finally, this paper provides a modified set of elastic constants for 4H-SiC with a view towards monocrystalline SiC MEMS devices.

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Section: B Pnc: Anchor Loss Mitigation Spurious Mode Suppressionmentioning

confidence: 99%

Section: Fabricationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Investigating Elastic Anisotropy of 4H-SiC Using Ultra-High Q Bulk Acoustic Wave Resonators

Yang

Hamelin

Ayazi

2020

J. Microelectromech. Syst.

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“…However, the limited deployment base of high-density dry etchers dedicated to SiC wafer-level processing severely obstructs basic research. To wit, there are few papers focused on deep reactive ion etching (DRIE) of SiC (4) and even fewer on DRIE of SiCOI substrates (5) for ultra-high Q MEMS applications (6). This paper focuses on the challenges in developing a SiC MEMS technology platform for applications requiring ultra-low dissipation.…”

Section: Introductionmentioning

confidence: 99%

(Invited) Nano-Precision Deep Reactive Ion Etching of Monocrystalline 4H-SiCOI for Bulk Acoustic Wave Resonators with Ultra-Low Dissipation

2020

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Integrated mechanical resonators with high quality factors (Q) made in high acoustic velocity materials are essential for a wide range of applications, including chemical sensors, timing resonators, and high-performance inertial sensors for navigation in GPS-occluded environments. While silicon is the most popular substrate for implementation of microelectromechanical systems (MEMS) resonators, SiC exhibits an exceptionally small intrinsic phononic dissipation due to high Akhiezer limits. This paper reports the latest results on nano-precision deep reactive ion etching (DRIE) of monocrystalline 4H SiC-on-Insulator (SiCOI) substrates to explore dissipation limits of bulk acoustic wave (BAW) SiC resonators. We report for the first time on capacitive Lamé mode resonators with ƒ·Q products beyond 1×1014 Hz. The contribution of surface roughness to dissipation and practical considerations to etch mirror-polished trenches in SiCOI substrates are discussed, paving the way towards micromechanical SiC resonators with Qs beyond 100 M.

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“…Enormous efforts have been made in recent years to demonstrate the high-quality factors (Q) of the bulk acoustic wave (BAW) mode resonator in comparison to flexural beam resonators [9]. However, the electrostatic actuation/detection of such stiff mechanical modes requires considerably high bias voltages [10][11][12][13][14][15][16][17]. The high voltage limits the practical applications of BAW resonators [18].…”

Section: Introductionmentioning

confidence: 99%

A Novel High Q Lamé-Mode Bulk Resonator with Low Bias Voltage

et al. 2020

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This work reports a novel silicon on insulator (SOI)-based high quality factor (Q factor) Lamé-mode bulk resonator which can be driven into vibration by a bias voltage as low as 3 V. A SOI-based fabrication process was developed to produce the resonators with 70 nm air gaps, which have a high resonance frequency of 51.3 MHz and high Q factors over 8000 in air and over 30,000 in vacuum. The high Q values, nano-scale air gaps, and large electrode area greatly improve the capacitive transduction efficiency, which decreases the bias voltage for the high-stiffness bulk mode resonators with high Q. The resonator showed the nonlinear behavior. The proposed resonator can be applied to construct a wireless communication system with low power consumption and integrated circuit (IC) integration.

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Capacitive Lamé Mode Resonators in $65\ \mu \mathrm{m}$-Thick Monocrystalline Silicon Carbide with Q-Factors Exceeding 20 Million

Cited by 13 publications

References 6 publications

Investigating Elastic Anisotropy of 4H-SiC Using Ultra-High Q Bulk Acoustic Wave Resonators

Investigating Elastic Anisotropy of 4H-SiC Using Ultra-High Q Bulk Acoustic Wave Resonators

(Invited) Nano-Precision Deep Reactive Ion Etching of Monocrystalline 4H-SiCOI for Bulk Acoustic Wave Resonators with Ultra-Low Dissipation

A Novel High Q Lamé-Mode Bulk Resonator with Low Bias Voltage

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