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A technique which retains wafer-scale processing and packaging compatibility is described for customizing the dynamics of individual silicon resonators. The approach uses laser ablation of a protective conformal layer (parylene) to expose silicon in regions that are targeted for mass removal by subsequent DRIE. The technique is demonstrated on a planar axisymmetric resonator design whereby the frequency...
We report a technique for defining high aspect ratio electrostatic gaps in micromachined glassblown spherical resonators. The approach is based on intentionally allowing a physical contact between the resonator and electrode structure, hence “collapsed electrodes”, then releasing and metalizing the electrodes and resonator. We utilized 500 um SOI electrodes in the glassblowing fabrication process,...
This paper demonstrates the effect of nonlinear elasticity on the coupling between different bulk modes of silicon MEMS resonators. From experimental data, we observe that the coupling has a strong dependence on the resonant mode order, the mode shape of the coupled modes, as well as the doping type / concentration, and crystal orientation, leading to a variety of complex and potentially useful phenomena.
This paper demonstrates the feasibility of a novel fabrication approach of MEMS resonators above standard CMOS circuitry and with zero-level vacuum package. As a proof of concept a monolithical CMOS-MEMS-closed loop oscillator showing dual-clock capabilities (11.9 MHz and 24.5 MHz) is presented. These two frequencies correspond to two different resonator modes, specifically the torsional and vertical...
This paper reports on a novel hybrid integration concept that enables the realization of high-quality (Q) factor, low-frequency coaxial cavity resonators with well-defined capacitive-loading and variable center frequency. It is based on a silicon-micromachined spacer that is mounted on top of a conventional CNC-machined metallic cavity to functionalize the resonator's capacitance. For the first time,...
This paper reports for the first time a piezoelectric inertial harvester for scavenging vibrational energy in all three dimensions. The harvester is formed of optimized bulk-PZT/Si crab legs such that the first three resonance vibrational modes are in-plane and out-of-plane translational modes with closely-spaced frequencies (387–398 Hz). Partitioned electrodes on the PZT arms collect mechanical energy...
We present the fabrication and characterization of a silicon micromirror with carbon nanotubes (CNTs)-nickel (Ni) composite beams, and evaluate the mechanical stability of the micromirror in terms of resonant frequency. A novel electroplating method is developed for the synthesis of the CNTs-Ni composite. The weight fraction of the CNTs in the electroplated composite is 2.6 wt%, and the ultramicroindentation...
In this work, an oxide-refill process is used to null the first-order temperature coefficient of frequency (TCF) of silicon MEMS resonators and to achieve high thermal resistance isolation structures. The technology enables fabrication of a low-power ovenized micro-platform on which multiple MEMS devices can be integrated. The intrinsic frequency-temperature characteristic of two resonators is utilized...
We propose a new approach for integration of electrodes as a part of the micro glass-blown spherical resonator fabrication process as well as an ALD metallization of the inner side of the spherical shell enabling electrostatic conduction. We use a 500µm thick silicon electrode whose electrostatic gap width, defined during the glass blowing process, is not limited by lithographic effect and enables...
This paper reports a 1.5 mm batch-fabricated polycrystalline diamond Cylindrical Resonator (CR) for gyroscope applications. The device is fabricated in a cylindrical shape using silicon on insulator (SOI) wafers and deep reactive ion etching (DRIE), which allows flexibility of choosing different geometries and materials for the resonator structure. A quality factor (Q) of 313,100 is measured at the...
This work presents chip-scale integration of MEMS resonant mass balances along with aerosol inertial impactors (airborne micro/nanoparticle collectors). A three mask microfabrication process has been developed to produce the main components; mass balance, impactor nozzle, and impaction micro-chamber on a single SOI substrate. In addition to extreme miniaturization of a conventionally bulky setup and...
We report a new design concept of micromechanical cantilever system incorporating the 1∶3 internal resonance during dynamic mode operation of atomic force microscopy (AFM). The passive amplification of third harmonic triggered through the mechanism of 1∶3 internal resonance enables AFM to utilize multiple harmonics in an air environment. Detailed theoretical and experimental studies of the proposed...
A four-channel external-cavity laser using one shared ring resonator, which provides a frequency grid, and four slave ring resonator enables us to select the lasing frequencies of the four subchannels from the grid frequencies. A proof-of-concept experiment, performed by butt-coupling an InP semiconductor optical amplifier to a Si wire waveguide external mirror chip, demonstrated lasing of each of...
Control of stress in porous silicon (PS) through porosity changes was studied using X-ray diffraction rocking curve measurements. The effect of thermal annealing on the stress was also investigated, which showed the ability to achieve compressive or tensile films in a reversible manner. The effect of stress on the resonant frequency of PS microbeams was studied to understand the impact of PS film...
In this paper, we report optical and mechanical properties of low temperature plasma enhanced chemical vapor-deposited (PECVD) amorphous hydrogenated silicon carbide (a-SiC:H) thin films. Initial screening of this process using hydrogen-dilution was performed with a two-level, three-parameter design of experiments (DOE) with eight samples. In this process regime, it was determined that the main parameters...
In order to clarify the source of resonant frequency drift in MEMS resonators, thermal expansion effect of packaging on MEMS devices was investigated. The strain in a silicon plate bonded on an aluminum plate with temperature was precisely measured. Increasing amount of strain in the aluminum plate was as large as 200 micro-strain with increase in only 20 degrees of temperature. The strain in the...
This paper presents a series of passive millimeter wave membrane supported circuits recently developed by the authors. Double folded slot antennas, band pass filters and band stop resonators are designed and fabricated by wet or dry etching of silicon. Flexible models are used for full-wave 3D electromagnetic simulations. The accuracy of the models is validated by measurement results. Membrane supported...
Piezoelectric microelectromechanical systems (MEMS) resonators on Si can be a potential candidate to replace discrete L-C components in series resonant converters. In this paper, ring shaped piezoelectric (AlN) micro-resonators on Si are reported. Having vibration in contour mode, these resonators can achieve resonant frequency as low as 87.28 MHz. Recently, we have fabricated high Q (>1000) piezoelectric...
This paper presents brief study of MEMS technology and development of condenser microphone with no holes in back plate. In general silicon materials are used in MEMs. MEMS devices can be fabricated by using bulk micromachining and surface micromachining. Microphone is designed by using a thin silicon crystalline material as flexible diaphragm and gold material as back plate. The aim of this paper...
We present a numerical simulation of frequency-agile terahertz metamaterials which incorporate semiconducting material as an integral part of the resonant elements to split ring resonator (SSR). The resonance frequency of the metamaterial can be dynamical tune through photoexcitation. The modification of capacitance at the split gap by photoexcitation results in red-shifting of metamaterial resonance...
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