In this study, a two-step deposition method using RF reactive magnetron sputtering is proposed to obtain high quality Piezoelectric ZnO thin films for film bulk acoustic resonators (FBARs). The titanium (Ti) seeding layer and platinum (Pt) bottom electrode were deposited by a dual gun DC sputtering system. The properties of thin film are investigated using the scanning electron microscope (SEM), Atomic force microscope (AFM) and the four-point probe method. The results show that the Pt bottom electrode deposited on the Ti seeding layer has lots of favorable characteristics, such as the crystallite size smaller than 10 nm, a surface roughness of 0.69 nm and a sheet resistance of 0.26 Ω/¡¼. The bottom electrode with the low resistance and the low surface roughness contribute markedly to the performances of the FBAR device. The Ttwo-step deposition method was adopted for ZnO thin film deposition, The 1st step deposition is focused on lowering the surface roughness of ZnO seeding layer films. The c-axis preferred orientation of ZnO film This is accompanied by the 2nd step deposition where the sputtering parameters O2 concentration arewere controlled to enhance the c-axis preferred growth of ZnO films. The AFM image shows that the surface roughness of the ZnO film is drastically reduced. It is also observed by monitoring the XRD spectra that the films deposited by two-step method reveal the high c-axis preferred orientation. Finally, the frequency response of ZnO-FBAR device using the two-step sputtering method shows the excellent performance at center frequency of 1.804GHz with the return loss of nearly 60dB and the electro-mechanical coupling coefficient of 3.2%.

In this study, ZnO film bulk acoustic resonators (FBARs) are proposed to fabricate the mass sensor of high sensitivity. The acoustic cavity is achieved by potassium hydroxide (KOH) etching. The FBAR structures are made of highly C-axis-oriented piezoelectric ZnO thin films using the technique of two-step deposition method. The titanium (Ti) seeding layer, platinum (Pt) bottom electrode, and aluminum (Al) top electrode were deposited by DC sputtering system using a dual gun. Finally, The remnants of silicon and silicon nitride (SiNx) are removed by reactive ion etching (RIE) etching. Furthermore, the two resonant frequencies of longitudinal mode and shear mode had been obtained. From the experimental results of loading effect with titanium and molybdenum, the mass sensitivity of the longitudinal mode and the shear mode are about 3200 Hz cm /ng and 1100 Hz cm /ng respectively, which are larger than those of quartz resonator or other reports. The measurement system was composed of a thermoelectric cooling module to investigate the temperature coefficient of frequency (TCF) of the mass sensor, which is about -70.67 ppm/. Bisides, the positive TCF material, silicon dioxode (SiO2) is deposited on ZnO thin films for the purpose of improving the TCF of FBAR devices. For SiO2/ZnO FBAR devices, the SiO2 reveal the compensation of TCF.

In this study, the FBAR devices fabrication was used by back-etched type. The titanium (Ti) seeding layer and platinum (Pt) bottom electrode were deposited by DC sputtering system using a dual gun. To improve the platinum (Pt) adhesion, a seeding layer titanium (Ti) is used. The piezoelectric zinc oxide (ZnO) thin films were deposited by RF reactive magnetron sputtering. By increase the substrate temperature and annealing treatment in order to improve the ZnO thin films quality. The FBAR device was fabricated with different top electrode of Al, Mo and Pt that was compared different frequency response characteristic. When ZnO thin films are deposited on Pt/Ti/SiNx/Si substrate by RF reactive magnetron sputtering, due to the lattice mismatch between the Zno thin film and Pt electrode and rapid deposition rate, the ZnO films have high Zn interstitials and O vacancy, which introduce the stress in ZnO films. By thermal annealing treatment the stress could be relaxed and the defects in ZnO films could be suppressed. We used the ZnO films at the different annealing temperature to fabricated the FBAR device, and also discussed the resonant characteristics of the FBAR device with the stress in the ZnO films. Top electrode of Al is suitable for using as electrode materials for FBAR device. The Al top electrode revealed the best frequency response characteristic among the various top electrodes in this research. Postdeposition annealing at 400¢Jmakes ZnO films more suitable for high Q FBAR device, it makes ZnO films with stronger c-axis (002) orientation, denser structure, smoother surface and relieved stress. The resonant frequency, the effective electromechanical coupling coefficient ( k eff ) and the quality factor (Q) were about 2.21GHz, 2.88% and 2659, respectively.

Filters having smallest size, high power handling capability, high Q factor, operating frequency up to several gigahertz’s (GHz) and low cost are the demand of the market to use in front end wireless/radio communication systems. In this regard several filter technologies have been introduced and utilized commercially. The increasing demand of such type of filters has opened a new challenge for filter designers. The purpose of this thesis is to design of a Tunable Bandpass Filter based on Barium Strontium Titanate (BSTO) Ferroelectric Film. A single Film bulk acoustic resonator (FBAR) is measured. MASON and Butterworth Van-Dyke (BVD) model are studied and implemented to reproduce the measurements. Simulations are performed by using the Advance Design System (ADS) by Agilent technologies. Simulations and measured data are used to exactly extract the physical and electrical parameters of a single FBAR. FBAR filter topologies are being studied and implemented. Ladder filter topology is selected to design the bandpass filter. The extracted physical and electrical parameters are used to investigate the performance of the filter. The area and the top electrode thickness of the series and shunt resonators are optimized to achieve the bandpass response with maximum out of band rejection, minimum insertion loss and sharper roll off near the pass band. A 3rd order T-type bandpass filter for 5GHz applications is designed. The insertion loss of -2.925 dB is achieved. The filter exhibits the 3dB bandwidth of 176 MHz and out of band rejection of -10 dB. DC bias of 0-25 V is used to analyze the tuning behavior of the filter.  The electromagnetic co-simulation is also done in momentum to analyze the parasitic effects between the resonators. The results show the good agreement between the schematic and momentum simulation. Layout and masks are also designed on a 10*10 mm wafer that will be used later to fabricate the filter and further investigations.

This study is to develop the manufacturing processes of thin film bulk acoustic device by MEMS technology, including lithography, wet etching, dry etching and rf Magnetron sputtering.LPCVD is used to deposit SiNx as the membranes and mask for etching of silicon wafer. The electrodes of molybdenum metal (Mo) and piezoelectric layer of aluminum nitride (AlN) on top side are prepared by dc and rf sputtering,respectively. The acoustic cavity on back side is achieved by 30%wt 100¢J KOH solution and reactive ion etching (RIE). In this study, the crystallography of the coated films was analyzed by X-ray diffraction. The surface and cross-sectional morphologies of AlN films were investigated by electron microscope. The piezoelectric layer of AlN thin film prepared by rf magnetron sputtering shows the highly c-axis preferred orientation and fine morphology under the optimal sputtering parameters of rf power of 200W, sputtering pressure of 3 mTorr, substrate temperature of 400¢J and nitrogen concentration of 25%. The frequency responses of fabricated FBAR devices are evaluated using the Hewlett-Packard 8720-ET network analyzer. Moreover, the optimal thickness of 1500Å SiNx film prepared by LPCVD revealed the excellent masking effect and non-stress for membrane. The yield for the fabrication of acoustic cavity is maximum of 85% can be achieved by using the combined etching steps of wet and dry etching.

ABSTRAT In this thesis, we focused on the fabrication and frequency-modulation of £f/4 mode dual-band solidly mounted resonators and filters. To accomplish the Bragg reflector, the RF/DC magnetron sputtering system with dual targets is adopted to deposit alternating layers of quarter-wavelength Mo and SiO2 thin films. We tune the fabrication parameters in accordance with the AFM measurement and achieve a low roughness of 2.9nm on a nine-layer reflector. The piezoelectric layer, aluminum nitride (AlN) thin films, is deposited on the Bragg reflector by means of reactive RF magnetron sputtering. We alter the distance between substrate and target is altered to deposit AlN with various c-axis tilting angle which results in longitudinal and shear acoustic waves at the same time. Furthermore, we use mass loading effect to modulate the resonance frequency and fabricate £k- ladder type filters. In various numbers of reflector layers, the optimum frequency response is obtained with return loss of -26dB, in a SMR on a 3.5 pair reflector. To investigate the relationship between longitudinal and shear resonance in different resonance frequency, we alter the c-axis tilting angle of AlN as well as various mass loading on the SMRs. Based on the experimental results, the ratio of longitudinal to shear resonance frequency remains a constant value despite various c-axis tilting angle of AlN and mass loading on the SMRs. In addition, the electromechanical coupling coefficient, Kt2, of shear resonance raises with the increase of c-axis tilting angle of AlN. Finally,we have successfully fabricated SMRs with frequency modulataion of 3,899.68 Hz-cm2/ng and £k-ladder type filters with 26 MHz bandwidth.

The purpose of this thesis is to design and fabricate Gigahertz range voltage controlled oscillator based on intrinsically tunable film bulk acoustic resonator.Modified Butterworth Van Dyke (MBVD) model was studied and implemented to simulate FBAR behavior. Advanced designed system (ADS) was used as the simulation tool.Oscillator theory is studied and an oscillator based on non-tunable FBAR at 2GHz is simulated which shows -132 dBc/Hz phase noise @ 100 kHz offset frequency.A 5.5 GHz Voltage controlled oscillator based on intrinsically tunable FBAR is designed. Frequency tuning of 129 MHz with phase noise of -106 dBc/Hz @ 100 kHz is achieved. The circuit is designed on a novel carrier substrate which includes integrated resonators and passive components. Bipolar junction transistors are mounted on the carrier substrate by silver epoxy. The thesis describes the design, development and processing of the carrier substrate, BSTO based resonators, and the oscillator circuit.

Shear-mode thin film bulk acoustic resonator (TFBAR) devices with c-axis tilted AlN films are fabricated for the application of liquid sensors. To fabricate shear-mode TFBAR devices, the off-axis RF magnetron sputtering method for the growth of piezoelectric AlN thin films is adopted and influences of the relative distance and the sputtering parameters are investigated. The shrar-mode phenomenon of a TFBAR results from the tilted crystalline orientation of AlN thin films. In this thesis, the AlN thin films are deposited with tilting angles of 15¢X and 23¢X, set by controlling the deposition parameters. The properties of the AlN thin films are investigated by X-ray diffraction and scanning electron microscopy. The frequency response is measured using an HP8720 network analyzer and a CASCADE probe station. The frequency response of the TFBAR device with 23¢X tilted AlN thin film is measured to reveal its ability to provide shear-mode resonance. The resonance frequencies of the longitudinal and shear modes are 2.07 GHz and 1.17 GHz, respectively. To investigate the sensing characteristics of TFBAR, two basic experiments of mass and liquid loading are carried out. The sensitivities of the longitudinal and shear modes to mass loading are calculated to be 2295 Hz cm2/ng and 1363 Hz cm2/ng with the mechanical quality factors of 588 and 337, respectively. However, the mechanical quality factors of the longitudinal mode of TFBAR without and with a liquid loading decreased from 588 to 0, whereas those remain almost the same for the shear mode under liquid loading. The sensitivities of the longitudinal and shear modes are calculated to be 0 and 17.88 Hz cm2/£gg for liquid loading.

<p dir="ltr">Gyroscopes have become an integral part of many application spaces ranging from consumer electronics to navigation. As navigation and movement tracking becomes necessary through inertial measurement units (that comprises gyroscopes and accelerometers) in myriad of scenarios especially when global navigation and satellite system (GNSS) is not available, stability of gyroscopes plays a detrimental role in the accuracy of navigation. Recent developments in micro-electromechanical systems (MEMS) based gyroscopes enabled them to penetrate into navigation grade application spaces. MEMS based miniaturization approach also revived the interest in nuclear magnetic resonance gyroscopes (NMRGs). In parallel, emerging atomic gyroscope technologies are getting attention such as using quantum defects in single crystal diamond. </p><p><br></p><p dir="ltr">Considering innovative ways MEMS can improve gyroscopes, we investigate solid state gyroscope technologies in piezoelectric MEMS and nuclear spin based platforms for next generation rotation sensing that is shock and vibration insensitive. For the first part of this study, we explore a piezoelectric resonator that can excite wine-glass mode (WGM) and tangential mode. WGM is used for rotation sensing applications in various excitation mechanisms in literature. However, we demonstrate the capability of exciting WGM without the need for segmented electrodes in piezoelectric domain that allows self-alignment of the excitation electrodes using a unique property of Lead Magnesium Niobate-Lead Titanate (PMN-PT). In the second part of the study, we explore Nitrogen-Vacancy (NV) centers in diamond to be used as gyroscopes exploiting the rotation sensitivity of nuclear spins. NV center-based gyroscopes provide solid-state solution with comparable or superior performance without any moving parts. We propose mechanical coupling to NV centers in diamond using piezoelectrically excited bulk acoustic waves (BAW) to extend the coherence time of nuclear spins by dynamical decoupling. We explore piezoelectric coupling design space of AlN thin film BAW resonators (FBARs) to enable efficient mechanical drive to improve Rabi oscillations in diamond to overcome one of the most important bottlenecks of realizing a gyroscope, which is the mitigation and control of nuclear spin and electron spin interaction in diamond NV center system.</p>

<p>En studie i hur känsligheten avtar från ytan hos biosensorer med höga frekvenser presenteras. Med ny teknologi som avancerade elektroakustiska tunnfilms komponenter, så kallade FBARs, blir tidigare outforskade områden som decay längden möjliga att studera.</p><p>För att undersöka hur frekvenssvaret och känsligheten påverkas av interaktioner långt ut från en sensoryta används proteinkemi. Ett protokoll har optimerats innehållande aktivering med EDC/NHS och fibrinogen för att säkerställa en jämn tjocklek och fördelning av ett adsorberat proteinlager över en yta.</p><p>Dessa ytor kontrollerades först med hjälp av ellipsometri och sedan i ett QCM instrument. Alla experiment med de högfrekventa FBAR sensorerna utfördes vid Ångströmslaboratoriet i Uppsala där pågående forskning inom området finns.</p><p>Resultaten bekräftar teorin om en avtagande känslighet i och med ett ökat avstånd från ytan. En experimentell genomförd och beräknad tjocklek för decay längden uppskattades som inte helt stämde överens med den teoretiskt beräknade.</p><p>En ny term föreslås då frekvenssvaret hos en biosensor planar ut. Detta är en effekt som sker vid dubbla tjockleken av den teoretisk beräknade tjockleken av decay längden och har fått namnet; detection length. Efter denna längd eller gräns observeras en inverterad signal som det än så länge inte finns någon förklaring till.</p> / <p>A study of the sensitivity decrease of biosensors working at high frequencies is presented. With new technology such as film bulk acoustic resonators (FBAR), issues like the decay length is no longer irrelevant theory but may cause limitation in the system as well as it offers new detection possibilities.</p><p>To investigate the frequency response and sensitivity, layer-on-layer construction chemistry was used. A protocol involving activation with EDC/NHS and coupling chemistry with fibrinogen was optimized to ensure accurate thickness and uniformly distribution of each layer over the surface.</p><p>Surfaces were characterized using null ellipsometry and the protocol was tested in a traditional quartz crystal microbalance (QCM). Experiments with the FBAR were preformed at the Ångström laboratory in Uppsala were there is ongoing research and development in FBAR technology.</p><p>The results confirmed the theory of decreasing frequency and sensitivity further out from the surface. An experimental and estimated thickness was calculated which to some extent correlates to the theoretically calculated decay length.</p><p>A new terminology is suggested when the frequency levels off. It occurs approximately at twice the distance and thickness of the theoretically calculated decay length and is given the name; detection length. Beyond the detection length an inverted signal is observed which cannot yet be explained for.</p>