Showing papers on "Thin-film bulk acoustic resonator published in 2005"
Patent•
15 Feb 2005TL;DR: In this paper, the authors proposed a thin-film bulk acoustic resonator with a laminated body having a first electrode comprised of at least one conductive layer formed on a supporting substrate, at least a part of the end face is positioned inside the second electrode.
Abstract: PROBLEM TO BE SOLVED: To reduce the spurious caused by a lateral vibration mode. SOLUTION: The thin film bulk acoustic resonator includes a laminated body having a first electrode comprised of at least one conductive layer formed on a supporting substrate, at least one piezoelectric layer adjacently formed on an upper surface of the first electrode, and a second electrode comprised of at least one conductive layer adjacently formed on an upper surface of the piezoelectric layer, and has a structure where an end face of the piezoelectric layer appears by removing the piezoelectric layer positioned near an outer peripheral edge of the second electrode and at least a part of the end face is positioned inside the second electrode. COPYRIGHT: (C)2006,JPO&NCIPI
46 citations
TL;DR: The aluminum nitride (AlN) thin film bulk acoustic resonator (FBAR) as discussed by the authors achieved a Q factor of 780 and an effective electro-mechanical coupling constant (k eff 2 ) of 5.36% at a resonant frequency of 2 GHz.
Abstract: This paper describes the development of the aluminum nitride (AlN) thin film bulk acoustic resonator (FBAR) using noble MEMS techniques for CMOS integration. An air-gap was fabricated under the resonator for acoustic isolation. Germanium (Ge) was used as a sacrificial layer to make the air-gap. This technique gives high CMOS compatibility. The resonator achieved a Q factor of 780 and an effective electro-mechanical coupling constant ( k eff 2 ) of 5.36% at a resonant frequency of 2 GHz.
44 citations
31 Oct 2005
TL;DR: In this paper, a thin film thickness excited shear acoustic wave resonator is presented for the fabrication of low cost biosensors, bioanalytical tools as well as for liquid sensing in general.
Abstract: A thin film thickness excited shear acoustic wave resonator is presented. Utilizing a newly developed reactive sputtering process AlN thin films with inclined c-axis relative to the surface normal with a mean tilt of around 30deg are successfully grown. Using the above process, a biosensor consisting of a shear mode thin film bulk acoustic resonator (FBAR) and a microfluidic transport system was fabricated. The biosensor operation in water, glycerol and albumin was characterized. The resonator had a resonance frequency of around 1.2 GHz and a Q value in water of around 150. Results concerning the stability and resolution are also presented. The results demonstrate clearly the potential of FBAR biosensors for the fabrication of highly sensitive low cost biosensors, bioanalytical tools as well as for liquid sensing in general
38 citations
18 Sep 2005
TL;DR: In this article, the authors outline concepts for the operation of a Thin Film Bulk Acoustic Resonator (FBAR) as a sensor for ambient pressure and material strains and develop a model to evaluate its sensitivity.
Abstract: In this contribution we will outline concepts for the operation of a Thin Film Bulk Acoustic Resonator (FBAR) as a sensor for ambient pressure and material strains. We develop a model to evaluate its sensitivity. Measurements with an FBAR solidly mounted on a silicon Wafer show the principal suitability of this device as a stress sensor. FBAR, Stress Sensor, ZnO
14 citations
Patent•
17 May 2005TL;DR: An air-gap type thin-film bulk acoustic resonator as mentioned in this paper has a substrate having a cavity formed on a predetermined portion of an upper surface thereof; a resonance part having a structure of a first electrode, a piezoelectric substance, and a second electrode deposited in order and formed over the upper side of the cavity; and at least one via hole penetrating a lower surface of the substrate and connecting to the cavity.
Abstract: An air-gap type thin-film bulk acoustic resonator. The air-gap type thin-film bulk acoustic resonator has a substrate having a cavity formed on a predetermined portion of an upper surface thereof; a resonance part having a structure of a first electrode, a piezoelectric substance, and a second electrode deposited in order and formed over the upper side of the cavity; and at least one via hole penetrating a lower surface of the substrate and connecting to the cavity.
13 citations
Patent•
03 Mar 2005
TL;DR: In this article, a thin-film bulk acoustic wave resonator and a micro electromechanical system (MEPS) was designed to eliminate the need of an etching process for a sacrificial layer, which is manufacturable while simplifying a manufacturing process and reducing energy loss.
Abstract: PROBLEM TO BE SOLVED: To provide FBAR (thin film bulk acoustic wave resonator) and MEMS (micro electromechanical system) devices which eliminate the need of an etching process for a sacrificial layer, is manufacturable while simplifying a manufacturing process and reduces energy loss SOLUTION: In this thin film bulk acoustic resonator, an acoustic reflection film 11 made of a material having an acoustic reflection function in a single layer is formed on a substrate 10, and an elastic resonance film 15 is formed on an upper layer of the acoustic reflection film 11 Otherwise, in a micro electromechanical system device, an elastic film with a bridge structure which is formed away with a prescribed distance in an operating area and formed so as to be in contact with a substrate at both ends of the operating area is formed on the substrate, and the acoustic reflection film made of the material having the acoustic reflection function in a single layer is formed between the elastic film and the substrate COPYRIGHT: (C)2005,JPO&NCIPI
11 citations
TL;DR: Based on sputtered AlN films, the prototype of AlN thin film bulk acoustic resonator (TFBAR) was fabricated successfully as discussed by the authors, which reached a full width at half maximum (FWHM) of 5.6°.
Abstract: Aluminum nitride is an attractive piezoelectric material for MEMS devices such as bulk acoustic wave (BAW) devices. (002)-oriented AlN films were deposited on Si, Al and Pt by reactive sputtering. Optimized AlN (002) peak reaches a full width at half maximum (FWHM) of 5.6°. Auger electron spectroscopy is used to analyze the oxygen contamination of films. To find the suitable electrode material for device application, the growth mechanism of AlN crystallites on different substrates is also discussed. Based on sputtered AlN films, the prototype of AlN thin film bulk acoustic resonator (TFBAR) was fabricated successfully.
11 citations
19 Dec 2005
TL;DR: In this paper, a balanced RF filter based on thin film bulk acoustic resonator (FBAR) technology for wireless applications is presented, and demonstrated its usage in the wideband code division multiple access (WCDMA) front-end as post-LNA filter.
Abstract: We present a balanced RF filter based on thin film bulk acoustic resonator (FBAR) technology for wireless applications, and demonstrate its usage in the wide-band code division multiple access (WCDMA) front-end as post-LNA filter The filter, which consists of two lattice sections and one symmetric ladder section, provides deep rejection at stop-band, particularly at transmitter band (1920-1980 MHz), steep roll-off at pass-band edges, and excellent common mode rejection ratio (CMRR) The typical broadband rejection is better than 60 dB The small size, low in-band insertion loss, sharp roll-off, high stop-band rejection, good temperature stability, and compatibility with semiconductor processing make this FBAR filter an ideal choice for GHz wireless applications
6 citations
Patent•
12 Jul 2005
4 citations
Patent•
31 Mar 2005
TL;DR: In this article, a piezoelectric thin film vibrator was used to vibrate a thin film bulk acoustic resonator, where the vibrator consisted of a substrate (101 b), an acoustic mirror layer ( 508 b), and an upper electrode ( 506 b ).
Abstract: A thin film bulk acoustic resonator ( 507 b ) comprises a substrate ( 101 b ), an acoustic mirror layer ( 508 b ) provided on the substrate ( 101 b ), including a plurality of impedance layers ( 502 b, 503 b ) alternatively having a high acoustic impedance and a low acoustic impedance, and a piezoelectric thin film vibrator ( 509 b ) provided on the acoustic mirror layer ( 508 b ), including a lower electrode ( 504 b ), a piezoelectric thin film ( 105 b ) and an upper electrode ( 506 b ). The sum of a thickness of the lower electrode ( 504 b ) and a thickness of the upper electrode ( 506 b ) is 5 % or more and 60 % or less of a whole thickness of the piezoelectric thin film vibrator ( 509 b ), and the thickness of the lower electrode ( 504 b ) is larger than the thickness of the upper electrode ( 506 b ).
4 citations
Journal Article•
TL;DR: In this article, two different kinds of structures (air-gragg,Bragg reflector), operating principles and modeling methods for FBAR were analyzed, and the key points of FBAR technology turn out to be the deposition of high c-axis oriented AlN thin film on Mo electrodes and the real time thickness measurement and control of thin film.
Abstract: Recent developments of FBAR at home and abroad were reviewed. Two different kinds of structures(air-gragg,Bragg reflector),operating principles and modeling methods for FBAR were analyzed. As a result,air-gap FBAR manufactured by surface micromachining with AlN thin film as the piezoelectric layer and Mo as the electrodes was referred. The key points of FBAR technology turn out to be the deposition of high c-axis oriented AlN thin film on Mo electrodes and the real time thickness measurement and control of thin film.
Patent•
04 Aug 2005
TL;DR: In this article, a thin-film bulk acoustic resonator manufacturing method was proposed, in which at least a lower part electrode, a piezoelectric film and an upper part electrode are laminated.
Abstract: PROBLEM TO BE SOLVED: To provide a piezoelectric film forming method which can manufacture a high membranous piezoelectric film with high productivity, a manufacturing method of an FBAR, and a non-reactive sputtering device realizing the methods. SOLUTION: In a thin-film bulk acoustic resonator manufacturing method having an elastic resonant film in which at least a lower part electrode, a piezoelectric film and an upper part electrode are laminated, a lower part electrode 12 is firstly formed on a substrate 10, and a piezoelectric film 13 is formed by a non-reactive sputtering which targets compound materials expressing piezoelectric property on an upper layer of the lower part electrode 12. Then, an upper part electrode 14 is formed on an upper layer of the piezoelectric film 13. COPYRIGHT: (C)2005,JPO&NCIPI
01 Jan 2005
TL;DR: In this article, a thin film bulk acoustic resonator (FBAR) filter was proposed for wideband code division multiple access (WCDMA) direct-conversion front-end applications.
Abstract: We present an Rx filter based on thin film bulk acoustic resonator (FBAR) technology for the wide-band code division multiple access (WCDMA) direct-conversion front-end applications. The filter, which consists of two lattice sections and one ladder section, provides deep rejection at stop-band, particularly at transmitter band (1920-1980 MHz), and steep roll-off at pass-band edges. The typical broadband rejection is better than 60 dB. The simulated result is compared with the up-to-date SAW filter, and demonstrates the excellent characteristics of the new FBAR filter. The small size, low in-band insertion loss, sharp roll-off, high stop-band rejection, good temperature stability, and compatibility with semiconductor processing make this FBAR filter an ideal choice for WCDMA Rx filter applications
Patent•
06 Jan 2005TL;DR: In this article, an improved method to control a piezoelectric coupling factor in a thin film bulk acoustic resonator was proposed, where a lower electrode (32), a composite layer (34) which was located on the lower electrode, and an apparatus (30) was provided with an upper electrode (36) above the composite layer and was manufactured on a substrate.
Abstract: PROBLEM TO BE SOLVED: To provide an improved method to control a piezoelectric coupling factor in a thin film bulk acoustic resonator. SOLUTION: There are provided a lower electrode (32), a composite layer (34) which is located on the lower electrode (32) and has a piezoelectric layer (34a) with a first coupling factor and a coupling factor control layer (34b) with a second coupling factor, and an apparatus (30) which is provided with an upper electrode (36) above the composite layer (34) and is manufactured on a substrate (12). COPYRIGHT: (C)2005,JPO&NCIPI
Patent•
03 Feb 2005TL;DR: In this article, the authors proposed a manufacturing method of an FBAR capable of being miniaturized, preventing the decline of mechanical strength and suppressing the degradation in the resonance characteristics of the FBAR solution.
Abstract: PROBLEM TO BE SOLVED: To provide a manufacturing method of an FBAR, capable of being miniaturized, preventing the decline of mechanical strength and suppressing the degradation in the resonance characteristics of the FBAR SOLUTION: The manufacturing method of the FBAR comprises a step of forming a lower electrode 20 above a hollow part on a substrate provided with the hollow part; a step of forming a piezoelectric film 22 on the surface of the lower electrode 20; a step of forming an upper electrode 24 facing the lower electrode 20 so as to hold the piezoelectric film 22 therebetween; a step of forming an opening 30 reaching the hollow part on the substrate; and a step of forming a void by removing a substrate part below the lower electrode 20 via the opening 30 and the hollow part COPYRIGHT: (C)2006,JPO&NCIPI
Patent•
17 May 2005
TL;DR: In this article, an air gap type thin film bulk acoustic resonator is proposed to provide high manufacturing yield in which resonance characteristics are enhanced as compared with that of prior art, where a substrate having a cavity formed in a predetermined region on the upper surface, a resonator having such a structure as a first electrode, a piezoelectric substrate and a second electrode are formed sequentially in layers, and at least one via hole communicating with the cavity while penetrating the lower part of the substrate.
Abstract: PROBLEM TO BE SOLVED: To provide an air gap type thin film bulk acoustic resonator exhibiting high manufacturing yield in which resonance characteristics are enhanced as compared with that of prior art. SOLUTION: The air gap type thin film bulk acoustic resonator comprises a substrate having a cavity formed in a predetermined region on the upper surface, a resonator having such a structure as a first electrode, a piezoelectric substrate and a second electrode are formed sequentially in layers, and at least one via hole communicating with the cavity while penetrating the lower part of the substrate. COPYRIGHT: (C)2006,JPO&NCIPI