Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
  • G01N29/22—Details, e.g. general constructional or apparatus details
  • G01N29/24—Probes
  • G01N29/2437—Piezoelectric probes
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
  • G01N29/02—Analysing fluids
  • G01N29/022—Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
  • G01N29/02—Analysing fluids
  • G01N29/036—Analysing fluids by measuring frequency or resonance of acoustic waves
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/02—Details
  • H03H9/05—Holders or supports
  • H03H9/0538—Constructional combinations of supports or holders with electromechanical or other electronic elements
  • H03H9/0547—Constructional combinations of supports or holders with electromechanical or other electronic elements consisting of a vertical arrangement
  • H03H9/0557—Constructional combinations of supports or holders with electromechanical or other electronic elements consisting of a vertical arrangement the other elements being buried in the substrate
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2291/00—Indexing codes associated with group G01N29/00
  • G01N2291/02—Indexing codes associated with the analysed material
  • G01N2291/025—Change of phase or condition
  • G01N2291/0256—Adsorption, desorption, surface mass change, e.g. on biosensors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2291/00—Indexing codes associated with group G01N29/00
  • G01N2291/04—Wave modes and trajectories
  • G01N2291/042—Wave modes
  • G01N2291/0426—Bulk waves, e.g. quartz crystal microbalance, torsional waves
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
  • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
  • H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
  • H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
  • H03H9/175—Acoustic mirrors

Definitions

• Ultra-high-precision mass sensing can be an important detection method such as for biomolecular and chemical detection. Detecting molecules by mass need not require chemical or fluorescent labeling, which can allow for simplified detection protocols and for sensing in systems adversely affected by labeling.
• the limited cross reactivity of fluorescently labeled generic binders can limit the specificity of a protein assay, such as used for analyzing or characterizing various cells, biomarkers, or autoimmune diseases, among others.
• use of unbound labeled reporters can also have limitations, such as preventing real-time detection and quantification of binding events, as such unbound reporters must be washed away prior to optical interrogation.
• FBAR thin-film bulk acoustic wave resonator
• CMOS complementary metal-oxide-semiconductor
• one or more individual FBAR mass sensors included in the array can be functionalized in a specified manner, such as for capturing a specific protein, nucleic acid, or gas molecule.
• An array of such functionalized sensors can allow simultaneous, multiplexed, high-sensitivity measurement of multiple targets (e.g., detection or measurement of multiple, different, species) on a single (e.g., monolithic) sensor chip.
• one or more FBAR-CMOS devices can be used as a filter, oscillator, or transformer, such as for microwave or solid-state power conversion applications, among others.
• the monolithic, solidly-mounted FBAR resonator apparatus can comprise a piezoelectric zinc oxide resonator atop a mechanically isolating acoustic mirror.
• the mirror can function as a mechanical analog to an optical Bragg stack, as acoustic waves are reflected back into the resonator through quarter-wavelength layers and constructive interference. Such reflection by the isolating acoustic mirror can inhibit or prevent coupling of acoustic energy into the substrate below the resonator.
• the apparatus optionally includes an integrated circuit substrate including an interface circuit, the first and second conductors electrically coupled to the interface circuit, the integrated circuit substrate configured to mechanically support the resonator, the acoustic mirror configured to inhibit or prevent coupling of acoustic energy from the piezoelectric region into the integrated circuit substrate at or near a resonant frequency of the thin-film bulk acoustic resonator.
• Example 2 the subject matter of Example 1 optionally includes a piezoelectric region comprising zinc oxide.
• Example 3 the subject matter of any one or more of Examples 1-2 optionally includes an acoustic mirror comprising alternating layers of tungsten and silicon dioxide.
• Example 4 the subject matter of any one or more of Examples 1-3 optionally includes an interface circuit comprising a CMOS circuit, and a resonator located on a top surface of the integrated circuit.
• Example 5 the subject matter of any one or more of Examples 1-4 optionally includes an oscillator including the acoustic resonator and at least a portion of the interface circuit.
• Example 6 the subject matter of any one or more of Examples 1-5 optionally includes an operating frequency of the oscillator determined at least in part by a mass loading the piezoelectric region.
• Example 7 the subject matter of any one or more of Examples 1-6 optionally includes a resonator comprising a sensing surface configured to detect at least one of a specified protein binding, a specified antibody-antigen coupling, a specified hybridization of a DNA oligomer, or an adsorption of specified gas molecules.
• Example 8 the subject matter of any one or more of Examples 1-7 optionally includes a sensing surface functionalized to adsorb gas molecules.
• Example 10 the subject matter of any one or more of Examples 1-9 optionally includes a sensing surface configured to increase in mass in response to at least one of a specified protein binding, a specified antibody-antigen coupling, a specified hybridization of a DNA oligomer, or an adsorption of specified gas molecules.
• Example 11 the subject matter of any one or more of Examples 1-10 optionally includes an oscillator configured to operate using a shear mode of mechanical oscillation of the resonator.
• Example 12 the subject matter of any one or more of Examples 1-11 optionally includes an oscillator configured to oscillate at the specified operating frequency when the apparatus is in contact with or surrounded by a liquid medium.
• Example 13 the subject matter of any one or more of Examples 1-12 optionally includes an integrated circuit comprising a frequency counter coupled to the oscillator and configured to provide information indicative of an oscillation frequency of the oscillator.
• an apparatus in Example 14, includes a thin-film bulk acoustic resonator array, each resonator comprising an acoustic mirror, a piezoelectric region acoustically coupled to the acoustic mirror, a first conductor electrically coupled to the piezoelectric region, a second conductor electrically coupled to the piezoelectric region and electrically insulated from the first conduct.
• the apparatus optionally includes an integrated circuit substrate including an interface circuit, the first and second conductors of each resonator electrically coupled to the interface circuit, the integrated circuit substrate configured to mechanically support the resonator array, and each respective acoustic mirror is configured to reduce or inhibit coupling of acoustic energy from the respective piezoelectric region into the integrated circuit substrate at or near a resonant frequency of the respective thin-film bulk acoustic resonator including the respective acoustic mirror.
• the array optionally includes an array of oscillators, each oscillator including at least one acoustic resonator and at least a portion of the interface circuit.
• Example 15 the subject matter of any one or more of Examples 1-14 optionally includes at least one oscillator in the array comprising a resonator having a sensing surface that is configured to detect at least one of a specified protein binding, a specified antibody-antigen coupling, a specified hybridization of a DNA oligomer, or an adsorption of specified gas molecules.
• the subject matter of any one or more of Examples 1-15 optionally includes an integrated circuit comprising a frequency counter coupled to at least one oscillator included in the array, and configured to provide information indicative of an oscillation frequency of the at least one oscillator.
• a method includes forming a thin-film bulk acoustic resonator on an integrated circuit substrate, such as including forming an acoustic mirror configured to reduce coupling of acoustic energy from a piezoelectric region into the integrated circuit substrate at or near a resonant frequency of the thin-film bulk acoustic resonator, forming a piezoelectric region acoustically coupled to the acoustic mirror, and electrically coupling a first conductor between a piezoelectric region and an interface circuit included in the integrated circuit substrate, electrically coupling a second conductor between the piezoelectric region and the interface circuit included in the integrated circuit substrate.
• Example 18 the subject matter of any one or more of Examples 1-17 optionally includes electrically coupling the first and second conductors to the piezoelectric region including depositing a metal.
• Example 20 the subject matter of any one or more of Examples 1-19 optionally includes forming an acoustic mirror including forming alternating layers of silicon dioxide and tungsten on a top surface of the integrated circuit substrate.
• Example 21 the subject matter of any one or more of Examples 1-20 optionally includes forming an array of thin-film bulk acoustic resonators on the integrated circuit substrate.
• Example 22 the subject matter of any one or more of Examples 1-21 optionally includes providing a sensing surface on the resonator to detect at least one of a specified protein binding, a specified antibody-antigen coupling, a specified hybridization of a DNA oligomer, or an adsorption of specified gas molecules.
• Example 23 the subject matter of any one or more of Examples 1-22 optionally includes functionalizing a sensing surface on the resonator to promote adsorption of specified gas molecules.
• Example 24 the subject matter of any one or more of Examples 1-23 optionally includes providing an oscillator using the resonator and at least a portion of the interface circuit, an operating frequency of the oscillator determined at least in part by a mass loading the piezoelectric region.
• Example 25 the subject matter of any one or more of Examples 1-24 includes providing a frequency counter configured to measure information indicative of an oscillation frequency of the oscillator, using at least a portion of the interface circuit.
• FIG. 1 illustrates generally an example of a side view of a section of a thin-film bulk acoustic resonator (FBAR) and an interface circuit.
• FIG. 2 illustrates generally an example of an oscillator circuit including an FBAR, and interface circuitry.
• FBAR thin-film bulk acoustic resonator
• FIG. 3 illustrates generally an example of a side view of a section of a solidly-mounted FBAR including an acoustic mirror portion.
• FIGS. 4A-I illustrate generally an example of post-CMOS fabrication of a monolithic thin-film bulk acoustic resonator (FBAR), such as included in array of FBAR-CMOS oscillators.
• FBAR monolithic thin-film bulk acoustic resonator
• FIG. 5 includes an SEM micrograph of an illustrative example of a solidly-mounted monolithic FBAR, such as fabricated according to the processing of the examples of FIGS. 4A-I.
• FIG. 6 includes two die photos of an illustrative example of a 6x4 array of FBAR-CMOS oscillators, including a first die photo after CMOS fabrication, and a second die photo after fabrication of the FBAR structures, such as fabricated according to the processing described in FIGS. 4A-I.
• FIG. 7A-C illustrate generally illustrative examples of electrical performance of a single FBAR structure, fabricated on glass.
• FIG. 8 illustrates generally an illustrative example of a plot of oscillation frequency versus a thickness of deposited silicon dioxide, such as for six different FBAR-CMOS oscillators included the 6x4 array of the example of FIG. 6.
• a specific antibody, antibody fragment, or nucleic acid probe can be immobilized on the surface of a mechanical sensor, such as a mechanical resonator.
• Target molecules can bind to the immobilized probe, further increasing the bound mass.
• mass sensing can be performed by electrically monitoring the resonant frequency of a lightweight, high-Q mechanical resonator, such as in contact with such bound material to be measured.
• An increase in mass at the resonator surface causes an overall decrease in the mechanical, and hence electrical, resonant frequency of the loaded system, and this frequency can be measured and used to determine the mass addition, such as in real-time as the bound material accumulates, and without requiring fluorescent labels.
• Quartz crystal microbalances have been used to detect antibodies and antigens, such as at sensitivities comparable to traditional labeled immunoassays.
• the resonant frequency can be limited by the thickness of self-supporting quartz (e.g., in the megaHertz range).
• the extent of frequency change per unit mass can be related to the square of the resonant frequency, thus limiting the QCM 's sensitivity.
• centimeter-scale QCM sensors can preclude high-density integration, which can limit QCM sensors to applications involving a relatively small number of target analytes.
• FBARs thin-film bulk acoustic resonators
• QCMs resonant structures
• an individual FBAR can be interfaced with active CMOS components such as through wire-bonding or flip-chip connection approaches (e.g., an
• an integrated array of FBARs can be built directly above active drive and readout circuitry (e.g., including CMOS circuitry).
• one or more individual mass sensors included in the array can be functionalized in a specified manner, such as for detecting binding of a specified protein, a specific antibody-antigen coupling, a specified hybridized DNA oligomer, or specified adsorbed gas molecules.
• An array of such functionalized sensors can allow simultaneous, multiplexed, high- sensitivity measurement of multiple targets (e.g., detection or measurement of multiple, different, species) on a single monolithic sensor assembly.
• the FBAR-CMOS sensor, or an array can be used for an immunoassay for industrial, medical, or agricultural use, among others, such as for identifying pathogens, contaminents, allergans, toxins, or other compounds.
• the FBAR-CMOS sensor, or an array can be used as a mass-sensor for gene-expression, either statically (e.g., at an endpoint of a reaction) or in real-time.
• the FBAR-CMOS sensor can be used for gas sensing or air sample monitoring, such as in response to surface modification (e.g., adsorption or vapor condensation) on a sensing surface included as a portion of the FBAR-CMOS sensor or array.
• FBAR resonators can also be used in microwave circuit applications. Such FBAR resonators can have relatively sharp resonances at high frequency, such as for use in filters, oscillators, or as transformers (e.g., transformers of voltage or impedance, etc.).
• FIG. 1 illustrates generally an example of a side view 100 of a section of a thin-film bulk acoustic resonator (FBAR) 102, including a sensing surface 116 electrically connected to a first electrode 112, a piezoelectric region 114, a second electrode 110, and an interface circuit 104.
• the interface circuit 104 can be electrically connected to the FBAR 102 such as using a first electrical connection 106A and a second electrical connection 106B, such as including a metal layer included in an integrated circuit.
• one or more of the first or second electrodes 112, 110 can include tungsten, such as sputtered or deposited on an integrated circuit substrate.
• the height of the FBAR 102 can be about 2 micrometers, and the width of the sensing surface 116 can be about 100 micrometers.
• the piezoelectric region 114 can include Zinc Oxide (ZnO), lead zirconate titanate (PZT), or one or more other piezopolymers, piezoceramics, or other piezoelectric materials.
• the FBAR 102 can resonate using a shear mode of oscillation, such as at a resonant operating frequency in the range of about 500 megaHertz, to more than 2 gigaHertz. In an example, such as shown in FIGS. 3, FIGS. 4A-I, and FIGS.
• a mechanical isolator such as an acoustic mirror, can inhibit or prevent coupling of acoustic energy at or near the resonant operating frequency of the FBAR 102 into the surrounding substrate, such as to provide a higher quality factor "Q" (e.g., a more sharply-peaked resonant operating frequency).
• Q quality factor
• FIG. 2 illustrates generally an example of an oscillator circuit 200 including an FBAR 202, and an interface circuit including MOS transistors Ml- M6.
• the circuit 200 of FIG. 2 can represent a single sensor such as included in an array of FBARs 202, such as a single sensor included in the 6x4 array shown in the examples of FIG. 6.
• the FBAR 202 can be connected to an inverting CMOS amplifier 204, the amplifier 204 including the MOS transistors M1-M6 such as to form an integrated FBAR- CMOS oscillator circuit 200.
• MOS transistors Ml -M6 need not literally include a metal gate, instead using polysilicon or other conductive gate material, such as fabricated using a commercial 0.18 micrometer CMOS fabrication process. Similarly, in an example, a semiconductor material other than silicon, or an oxides other than silicon dioxide can be used to realize one or more of transistors Ml -M6.
• the oscillator circuit 200 can include a Pierce oscillator topology.
• the inverting amplifier 204 can be implemented as three in-line CMOS inverters realized by the MOS transistors M1-M6, such as to provide gain to overcome the FBAR material losses, sustaining oscillation.
• a MOS transistor M7 can provide bias to MOS transistors M1-M6.
• transistor M7 can include a voltage-controlled gate, such as adjusted to balance biasing strength against oscillator loading.
• transistor M7 can be controlled by a voltage at a node V BIAS , such as to calibrate the oscillator circuit or to otherwise accommodate variations in individual FBAR sensors due to design or fabrication variations, or other sources of variation.
• an output voltage at a node V O U T can be provided to a co-integrated or off-chip analog or digital frequency counter, such as to provide continuous monitoring or sampling of the output frequency of the oscillator 200 during specified intervals of operation (e.g., to measure a shift in frequency corresponding to an increased mass, or for one or more other uses).
• a first capacitor Cl and a second capacitor C2 can promote oscillator startup.
• Cl and C2 can include metal- insulator-metal (MIM) capacitors that can be set to approximately equal values.
• MIM metal- insulator-metal
• the term metal-insulator-metal need not refer literally to metal plates, as capacitors Cl and C2 can be co-integrated on the same monolithic CMOS integrated circuit as transistors M1-M7.
• the FBAR 102 can be represented by an equivalent Butterworth-Van Dyke circuit, as shown in FIG. 2.
• the FBAR 300 can be fabricated on top of a first, a second, and a third passivation region 320A-C of an integrated circuit, such as either a passive substrate 304 or an active integrated circuit substrate 304.
• the FBAR 300 can be fabricated on an integrated circuit without passivation regions 320 A-C (e.g., such as in-line, prior to passivation, along with other processing during fabrication of the active circuitry portion of the sensor assembly).
• a first electrode 312 can be electrically connected to a first top metal layer region 322A of the integrated circuit
• a second electrode 310 can be electrically connected to a second top metal layer region 322B of the integrated circuit.
• a solidly-mounted FBAR 300 structure can allow simple fabrication, such as described in FIGS. 4A-I, unlike other bulk acoustic wave structures, such as those including a membrane.
• the FBAR 300, or an array of FBARs 300 can be built up via sequential deposition and patterning of each layer without requiring undercutting or sacrificial layer integration processes, such as might be used in fabricating other types of bulk acoustic wave structures.
• the FBAR 300 can include a sensing surface 316, such as formed by a portion of the first electrode 312.
• the sensing surface 316 can be coupled to a piezoelectric region 314 (e.g., ZnO or one or more other piezoelectric materials).
• the FBAR 300 of FIG. 3 includes an acoustic mirror, such as to mechanically isolate the mechanically resonant portion of the FBAR 300 from the rest of the mechanically supporting substrate 304 (e.g., below the passivation regions 320A-C).
• a mechanical resonator can be mechanically isolated from its supporting substrate, such as to help avoid dissipating too much energy into its surroundings (which could dampen and likely prevent oscillation).
• this isolation can be accomplished with an air gap, where the FBAR 300 structure can be implemented as a membrane or cantilever structure.
• the isolation can be accomplished through a dielectric acoustic mirror. Such isolation can allow the FBAR 300 to operate with a sharply-peaked resonant response despite being solidly-mounted to the substrate 304.
• one or more alternating layers of relatively high- and relatively low- acoustic-impedance material can be used, such as to provide a mechanical analog to a distributed Bragg reflector.
• the layers 318 and 320 can be sized and shaped to promote constructive interference of acoustic energy at or near the resonant operating frequency of the FBAR 300, at the interfaces between the layers 318 and 320, and between the electrode 310 and the piezoelectric region 314, reflecting a majority of acoustic energy back towards the piezoelectric region 314.
• the conductive layer 320 can be tungsten
• the insulating layer 318 can be silicon dioxide, or one or more other insulating materials.
• the second electrode 310 can also be used as the top layer in the acoustic mirror.
• FIGS. 4A-I illustrate generally an example of post-CMOS fabrication of a monolithic thin-film bulk acoustic resonator (FBAR) 400, such as included in array of FBAR-CMOS oscillators.
• the fabrication processes of FIGS. 4A-I need not require specialized fabrication techniques or non-standard CMOS fabrication processes (e.g., such fabrication can include processing and materials similar to that used for commercial digital or mixed signal CMOS device fabrication).
• the post-CMOS fabrication of the FBAR 400A can begin with a commercial integrated circuit substrate 404, such as including one or more openings in a passivation layer, exposing one or more metal regions.
• the integrated circuit substrate 404 can include an active CMOS substrate (e.g., an integrated circuit substrate including one or more active devices or circuits), such as fabricated using a commercial 0.18 ⁇ m foundry CMOS process, or using one or more other fabrication processes.
• the post-CMOS substrate 404 can be patterned, such as using a relatively thick photoresist layer (e.g., about 1 micrometers to 8 micrometers, or using another thickness).
• the metal layer 420 and insulating layer 418 in the regions above the remaining photoresist can be lifted off (e.g., with ultrasonic assistance), or otherwise removed from the FBAR 400C, leaving behind the metal layer 420 and insulating layer 418, such as between the passivation openings in the substrate 404, on a working top surface of the substrate 404.
• the metal layer 420 and insulating layer 418 can form at least a portion of an acoustic mirror as discussed above in FIG. 3. In FIG.
• the FBAR 400D can again be patterned, and a top tungsten acoustic mirror layer 410 (or another conductive material) can be deposited or sputtered onto the exposed portions of the FBAR 400D above a working top surface region of the substrate 404.
• the top tungsten mirror layer 410 can also serve as the bottom electrode of the FBAR 400D, and this layer can connect to the top metal layer of the CMOS substrate such as through an opening in the passivation layer 404.
• the unwanted portions of the tungsten mirror layer 410 can be lifted off or otherwise removed from the FBAR 400E.
• the FBAR 400H can be patterned, and a top electrode 416 can be sputtered or otherwise deposited.
• the unwanted portions of the top electrode 416 can be lifted off, or otherwise removed from the FBAR 4001.
• the top electrode 416 can include a top tungsten contact (e.g., about 200 nanometers thick) can be patterned and can connect through CMOS top metal to the underlying circuitry (e.g., an oscillator, amplifier, interconnect, or other circuitry elsewhere).
• the piezoelectric material can provide insulation in a lateral region of the FBAR 400G, such as to prevent electrical shorting between the top electrode 416, and one or more other regions, such as the mirror layer 410.
• FIG. 6 includes two die photos of an illustrative example of a 6x4 array of FBAR-CMOS oscillators, including a first die photo 600A after CMOS fabrication but prior to fabrication of the FBAR structures, and a second die photo 600B after fabrication of the FBAR structures, such as fabricated according to the processing described in FIGS. 4A-I.
• first die photo 600A one or more test regions can be included on the die, such as for characterizing circuitry included in the die, or for testing one or more regions fabricated using similar materials or structures as used elsewhere in the array.
• each FBAR-CMOS oscillator can include its own acoustic mirror, isolated from the surrounding oscillators, such as including one or more fabrication processes or structures such as shown and discussed above in FIG. 3, and FIGS. 4A-I.
• two or more FBAR structures can be formed or can incorporate a commonly-shared "blanket” acoustic mirror, such as formed or built up in a region underlying the two or more FBAR structures.
• FIG. 7A-C illustrate generally illustrative examples of electrical performance of a single FBAR structure similar to the structure shown and discussed above in the examples of FIG. 3, and FIGS. 4A-I.
• the relative slope regions of a phase noise plot 770 indicate a loaded Q for the oscillator of 218 in accordance with Leeson's phase noise relationship, where a knee in the plot 770 at f o /2Q can represent a transition to a relatively flat, white- noise dominated phase noise response.
• measurement integration e.g., averaging or integrating multiple frequency or interval measurements during a specified measurement timeframe
• FIG. 7C shows an illustrative example of the output amplitude spectrum 780 (plotted in dB), with respect to frequency 700 (in megaHertz) as measured at the output of one on-chip FBAR-CMOS oscillator, including a peak 790 at about 864.5 megaHertz.
• oscillators across array can demonstrate a spread of -10 megaHertz in resonant frequency as compared to one another, such as due to variations in zinc oxide thickness, or other factors.
• FIG. 8 illustrates generally an illustrative example of a plot of an oscillation frequency 810 (in megaHertz) versus a thickness 800 (in nanometers) of deposited silicon dioxide, such as for six different FBAR-CMOS oscillators included a 6x4 array of the example of FIG. 6.
• the fundamental oscillation frequencies of each of the six oscillators can be measured first as a baseline, after which mass can be added (e.g., by forming successive layers of patterned silicon dioxide, RF sputtered onto the FBAR top surfaces, such as a sensing surface).
• the Sauerbrey equation predicts a linear change in frequency for small additions of uniform-thickness mass, similar to the responses shown in the illustrative example of FIG. 8, with the average mass sensitivity of the examples of FIG.

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• Physics & Mathematics (AREA)
• Biochemistry (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Acoustics & Sound (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
• Oscillators With Electromechanical Resonators (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

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• 2010
  • 2010-04-29 EP EP10770334.0A patent/EP2425468A4/de not_active Withdrawn
  • 2010-04-29 CN CN201080018971.9A patent/CN102414855B/zh not_active Expired - Fee Related
  • 2010-04-29 CA CA2760508A patent/CA2760508A1/en not_active Abandoned
  • 2010-04-29 WO PCT/US2010/032976 patent/WO2010127122A1/en not_active Ceased

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