Techniques for Tuning BAW-SMR Resonators for the 4th Generation of Mobile Communications (original) (raw)
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A multiple resonant mode film bulk acoustic resonator based on silicon-on-insulator structures
Chinese Physics Letters, 2014
We report a multiple resonant mode film bulk acoustic resonator (FBAR) with different AlN film thicknesses of 605 nm, 640 nm and 680 nm. With the tilted c-axis orientation of the AlN piezoelectric film providing polarization vertical to the c-axis, acoustic wave resonant peaks have been observed for both the thickness shear modes (TSM 0th, TSM 1st, TSM 2nd) and the thickness extension modes (TEM 0th, TEM 1st). The corresponding parallel resonant frequencies are around 1.60 GHz, 2.41 GHz, 3.45 GHz, 2.75 GHz and 4.10 GHz, respectively. The latter two TEM modes also have good quality factors, and high equivalent electromechanical coupling coefficients Keff2 of 647, 3.13% and 113, 6.23%, respectively. By etching the 1.8 μm silicon sacrificial layer, the air gap FBAR devices have been fabricated in an easier and cleaner way resulting in a low insertion loss of −2.2 dB. The overall device structure of the top electrode/AlN film/bottom electrode on SiO2/silicon-on-insulator (SOI) substrate potentially enables CMOS compatibility. These multiple resonant mode FBAR devices will promote the integration of multi-band filters on a single chip. Improvements of the fabrication process, the influence of different AlN film thicknesses and theoretical analyses of the coexistence of multiple resonant modes are presented.
Materials for bulk acoustic wave (BAW) resonators and filters
Journal of the European …, 2001
Thin film bulk acoustic wave (BAW) resonators and filters are appropriate for mobile communication systems operating at high frequencies between 1-10 GHz. The resonance frequency is mainly determined by the thickness of the piezoelectric layer. Piezoelectric films used for this application are, therefore, several 100 nm in thickness (up to approx. 2 mm) depending on frequency. Piezoelectric thin film materials used for bulk acoustic wave devices include AlN, ZnO thin films for small bandwidth applications and also PZT films for wide bandwidth applications. Within Philips piezoelectric AlN and PbZr x Ti 1Àx O 3 (PZT) layers are investigated with respect to their potential for RF micro-electronic applications. High quality AlN films with strong c-axis orientation are achieved by optimum sputter deposition conditions and by applying suited nucleation layers. Electromechanical coupling factors k of 0.25 AE0.03, which are close to the bulk data, have been found in highly c-axis oriented AlN thin films. The relationship between sputter deposition conditions, AlN films structure on the one hand and electromechanical coupling factor k and relevant electrical parameters on the other hand will be discussed. A one-dimensional physical model is used to describe the bulk acoustic wave resonator's electrical impedance data accurately. Thin PZT films are grown via sol-gel processing. These films show high electromechanical coupling factor k of 0.3-0.6 and are therefore attractive for wide bandwidth filter applications. #
Silicon Compatible Acoustic Wave Resonators: Design, Fabrication and Performance
IIUM Engineering Journal
ABSTRACT: Continuous advancement in wireless technology and silicon microfabrication has fueled exciting growth in wireless products. The bulky size of discrete vibrating mechanical devices such as quartz crystals and surface acoustic wave resonators impedes the ultimate miniaturization of single-chip transceivers. Fabrication of acoustic wave resonators on silicon allows complete integration of a resonator with its accompanying circuitry. Integration leads to enhanced performance, better functionality with reduced cost at large volume production. This paper compiles the state-of-the-art technology of silicon compatible acoustic resonators, which can be integrated with interface circuitry. Typical acoustic wave resonators are surface acoustic wave (SAW) and bulk acoustic wave (BAW) resonators. Performance of the resonator is measured in terms of quality factor, resonance frequency and insertion loss. Selection of appropriate piezoelectric material is significant to ensure suffic...
2019 Symposium on Design, Test, Integration & Packaging of MEMS and MOEMS (DTIP)
This paper presents a feasibility study on the design of piezoelectric MEMS lateral bulk acoustic wave resonators with particular reference to the thermal effect on the resonant frequency. This study compares the results obtained from both analytical models as well as finite element simulations with the temperature effects included. This comparative study has been carried out on resonators having a resonant frequency of around 19.5 MHz using two different Thin-Film Piezoelectricon-Substrate (TPoS) MEMS processes: the first process consists of a 1 µm PZT layer over an SOI structure having a thickness of 5.5 µm, while the second process is the PiezoMUMPs MPW process consisting of a 0.5 µm AlN layer over an SOI structure having a thickness of 10 µm. Both the analytical and the finite element models indicate a frequency variation of 300 kHz over a temperature range of 273-573 K. Based on these results, a number of PiezoMUMPs resonator prototypes, including a thermal heating element, have been designed in order to explore the feasibility of fine tuning the resonant frequency using the thermal effect. The possibility of fine tuning can be applied to high precision timing circuits such as frequency counters.
2021
This paper reports, the application of Taguchi Design of Experiments (DoE) and ANOVA (Analysis of Variance) for finding the optimal combinations and analysis of the effect of individual layer thickness on the performance of SMR sensor. The optimum combination of design parameters and its performance as a sensor have been predicted with DoE and validated through the finite element modeling (FEM) simulation. The optimization has been done to achieve enhancement in coupling coefficient of SMR sensor. The best optimized thickness of metal electrodes, piezoelectric, sensing, insulation low and high acoustic impedance layers have been found to be 0.2µm, 2µm, 0.68µm, 0.3µm, 1.028µm and 1.008µm, respectively. The results of the present study show that for the optimized dimension of SMR structure, simulated values of coupling coefficient (K2eff), Quality factor (Q) and figure of merit (FoM) are 0.075596 (or 7.5596%), 1171.6 and ≈ 88, respectively. Optimized structure performance has been com...
FILM BULK ACOUSTIC WAVE RESONATOR IN RF FILTERS
Film Bulk Acoustic Resonator (FBAR) is widely used as a RF filter in advanced wireless communication system because of its high-Quality Factor (Q) and low inband losses. FBAR is also widely used as a sensor for biomedical and physical sensing. This paper describes the basic concepts of FBAR, device architecture, and the topology used to design the filter. Furthermore, we have proposed the design of 3D-FBAR based on cavity device architecture which can be used to design a RF-filter. In this design, aluminum (Al) is used as a top as well as for the bottom electrode the top electrode is hexahedron in shape, aluminum nitride (AlN) as a piezoelectric and silicon (Si) is used as a substrate. The designed model is to analyses maximum pressure of FBAR in its operating region, the resonant frequency fr which is 2.76 GHz and anti-resonant frequency fa which is 2.78 GHz and Qfactor is 730.
Design and simulation of Bulk acoustic wave MEMS resonator
A brief review on the use of acoustic waves in designing MEMS based resonator is described in this paper. Acoustic devices can be further classified into two basic types – Surface acoustic wave (SAW) and Bulk acoustic wave (BAW) devices. A BAW resonator is modeled and simulated using COMSOL Multiphysics 4.3. In this model variation in thickness and piezoelectric material is the prime focus for studying the basic variation in series resonance and surface deformation of the device.
Proc. of Nano Science and Technology Institute (NSTI) Nanotechnology Conf, 2005
An approach of integrating multiple film bulk acoustic resonators (FBAR) with different frequencies is presented. Conventional FBAR structures were modified by adding a patterned tuning layer on top of Metal/AlN/Metal film stack. By controlling the dimensions of the periodic tuning pattern, resonance frequencies can be modulated due to mass loading effects. As a result, multiple-frequency resonators can be lithographically defined by a single deposition/patterning processing sequence. From finite element analysis, it was found that ...
Prototype Design of a Thin-Film Bulk Acoustic-Wave Resonator by the Finite Element Method
IEEE Transactions on Magnetics, 2000
A thin film bulk acoustic wave resonator (FBAR) used in the RF frequency region of a few gigahertz is considered and its impedance is evaluated by using a harmonic analysis with the three-dimensional finite element method. In particular, the spurious characteristics caused by variations in the electrode area, as well as all the resonant modes and the mode shapes are analyzed. A design procedure is presented by using a prediction software tool. An experimental prototype is built and the measured results are compared to the numerical ones.
This report is prepared to fulfill the partial requirement for "MLZ-323 Solid State Physics in Materials Science" lecture. The main objective is to conduct a literature survey on Thin Film Bulk Acoustic Wave Resonators in wireless communication technology and to carry out a materials and process selection procedure which is compatible with the aims of the lecture. The report covers general infomation about bulk acoustic wave resonator technology, architecture and working principle of thin film bulk acoustic wave resonators, a comparison between widely used piezoelectric materials for these devices and a tensoral representation of piezoelectric properties of AlN in wurtzite crystal form, and a proposition for processing method. Furthermore, characterization procedures and minimum thin film thickness determination is also introduced in the last section. Contents: