JP2006352619A - Piezoelectric thin-film resonator - Google Patents

Piezoelectric thin-film resonator Download PDF

Info

Publication number
JP2006352619A
JP2006352619A JP2005177500A JP2005177500A JP2006352619A JP 2006352619 A JP2006352619 A JP 2006352619A JP 2005177500 A JP2005177500 A JP 2005177500A JP 2005177500 A JP2005177500 A JP 2005177500A JP 2006352619 A JP2006352619 A JP 2006352619A
Authority
JP
Japan
Prior art keywords
film
piezoelectric
temperature coefficient
frequency temperature
piezoelectric thin
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2005177500A
Other languages
Japanese (ja)
Inventor
Keiichi Nakanishi
圭一 中西
Yoshiharu Sato
芳春 佐藤
Hiroko Onoda
寛子 小野田
Toshibumi Koike
俊文 小池
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toko Inc
Original Assignee
Toko Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toko Inc filed Critical Toko Inc
Priority to JP2005177500A priority Critical patent/JP2006352619A/en
Publication of JP2006352619A publication Critical patent/JP2006352619A/en
Pending legal-status Critical Current

Links

Images

Landscapes

  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric thin-film resonator having proper resonance characteristics and reducing the spuriousness of its resonance waveform. <P>SOLUTION: The piezoelectric thin-film resonator supported with a substrate has a piezoelectric film held between electrodes in an upper part of a gap formed on the substrate, and comprises a first frequency temperature coefficient correcting film between the substrate and the lower electrode, and a second frequency temperature coefficient correcting film on the upper electrode surface, to hold the piezoelectric film between the frequency temperature coefficient films from above and below. The second frequency temperature coefficient correcting film may be provided in between the upper electrode and the piezoelectric film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、電極で挟まれた圧電薄膜を利用する圧電薄膜共振子に係るもので、その特性の改善を図る構造に関するものである。   The present invention relates to a piezoelectric thin film resonator using a piezoelectric thin film sandwiched between electrodes, and relates to a structure for improving the characteristics thereof.

圧電薄膜共振子はGHz帯等の高周波領域で用いる共振子として注目されている。これは、シリコン等の基板上に電極に挟まれた窒化アルミニウム（AlN）や酸化亜鉛（ZnO）などの圧電膜を形成し、圧電膜の下側にも自由振動空間を設ける構造を採用している。上記のような圧電膜は、一般的に負の周波数温度係数を有しており、この負の温度特性を補正するために正の周波数温度係数を有する二酸化シリコン（SiO2）などの組み合わせることが考えられており、これによって零周波数温度係数の圧電薄膜共振子を得ることができる。 Piezoelectric thin film resonators are attracting attention as resonators used in high frequency regions such as the GHz band. This employs a structure in which a piezoelectric film such as aluminum nitride (AlN) or zinc oxide (ZnO) sandwiched between electrodes is formed on a substrate such as silicon, and a free vibration space is provided below the piezoelectric film. Yes. The piezoelectric film as described above generally has a negative frequency temperature coefficient, and in order to correct this negative temperature characteristic, a combination of silicon dioxide (SiO 2 ) having a positive frequency temperature coefficient can be combined. Thus, a piezoelectric thin film resonator having a zero frequency temperature coefficient can be obtained.

図５は、そのような圧電薄膜共振子の例を示す正面断面図である。シリコン基板40の表面に周波数温度係数補正膜42を形成し、その上に下部電極43、圧電膜44、上部電極45を形成したものである。圧電膜44の振動部の下には空隙41を形成しておく。この例では、空隙41はあらかじめシリコン基板に犠牲層を形成しておき、膜の形成後にその犠牲層の部分を除去することによって形成する。図５は空隙をシリコン基板の裏面からのエッチングで形成したもので、周波数温度係数補正膜、下部電極、圧電膜、上部電極の構造は同じである。   FIG. 5 is a front sectional view showing an example of such a piezoelectric thin film resonator. A frequency temperature coefficient correction film 42 is formed on the surface of the silicon substrate 40, and a lower electrode 43, a piezoelectric film 44, and an upper electrode 45 are formed thereon. A gap 41 is formed below the vibrating portion of the piezoelectric film 44. In this example, the gap 41 is formed by previously forming a sacrificial layer on the silicon substrate and removing the sacrificial layer portion after the film is formed. In FIG. 5, the air gap is formed by etching from the back surface of the silicon substrate, and the structure of the frequency temperature coefficient correction film, the lower electrode, the piezoelectric film, and the upper electrode is the same.

しかし、正の周波数温度係数の材料の音響インピーダンスと圧電膜の音響インピーダンスは異なるため、この音響インピーダンスの差によって図６に示すようにスプリアスを発生させてしまう。このスプリアスが共振子として利用する周波数帯域内あるいはその近傍に発生することによって、無視できない特性の劣化を生じてしまう。
特開２０００−３０７３７７号公報 特開２００１−２０３５５８号公報 特開２００２−８５７９号公報 However, since the acoustic impedance of the material having a positive frequency temperature coefficient and the acoustic impedance of the piezoelectric film are different, spurious is generated as shown in FIG. When this spurious is generated in the frequency band used as a resonator or in the vicinity thereof, degradation of characteristics that cannot be ignored occurs.
JP 2000-307377 A JP 2001-203558 A JP 2002-8579 A

本発明は、共振波形のスプリアスを低減し、良好な共振特性を有する圧電薄膜共振子を提供するものである。   The present invention provides a piezoelectric thin film resonator having reduced resonance waveform spurious and good resonance characteristics.

本発明は、圧電膜を挟んで２つの周波数温度係数補正膜を形成することによって、上記の課題を解決するものである。すなわち、基板に支持されてそこに形成された空隙の上部に電極に挟まれた圧電膜を具えた圧電薄膜共振子において、基板と下部電極間に第1の周波数温度係数補正膜を具えるとともに、上部電極の表面に第2の周波数温度係数補正膜を具えたことに特徴を有するものである。上部電極と圧電膜の間に第2の周波数温度係数補正膜を具えるようにしてもよい。 The present invention solves the above problem by forming two frequency temperature coefficient correction films with a piezoelectric film interposed therebetween. That is, in a piezoelectric thin film resonator comprising a piezoelectric film sandwiched between electrodes supported by a substrate and formed in an upper portion of a gap formed therein, a first frequency temperature coefficient correction film is provided between the substrate and the lower electrode. Further, the second frequency temperature coefficient correction film is provided on the surface of the upper electrode. A second frequency temperature coefficient correction film may be provided between the upper electrode and the piezoelectric film.

SiO2などの周波数温度係数補正膜を圧電膜の上下に配置することによって共振波形のスプリアスを低減することができる。圧電薄膜共振子は主としてその厚み縦振動の縦効果を利用する共振子であるが、実際には横効果も存在する。圧電膜を挟む電極の音響インピーダンスが極端にアンバランスな場合、薄膜中に振動変位の偏りが生じ、その結果、横効果振動を強く励振してしまうのでスプリアスが発生する。この振動変位の偏りをなくし、スプリアスを低減させるためには圧電膜を挟む物質の音響インピーダンスをバランスよく配置することが効果的である。 By arranging frequency temperature coefficient correction films such as SiO 2 above and below the piezoelectric film, the spurious of the resonance waveform can be reduced. A piezoelectric thin film resonator is a resonator that mainly uses the longitudinal effect of its thickness longitudinal vibration, but there is also a lateral effect in practice. When the acoustic impedance of the electrodes sandwiching the piezoelectric film is extremely unbalanced, vibration displacement is biased in the thin film, and as a result, the lateral effect vibration is strongly excited and spurious is generated. In order to eliminate this vibration displacement bias and reduce spurious, it is effective to arrange the acoustic impedance of the material sandwiching the piezoelectric film in a balanced manner.

本発明による圧電薄膜共振子の構成要素は以下のとおりである。
（１）空隙を具えた基板
（２）下側の周波数温度係数補正膜
（３）下地電極
（４）圧電膜
（５）上部電極
（６）上側の周波数温度係数補正膜
(5)と(6)の位置関係を逆にしてもよい。 The components of the piezoelectric thin film resonator according to the present invention are as follows.
(1) Substrate with a gap (2) Lower frequency temperature coefficient correction film (3) Base electrode (4) Piezoelectric film (5) Upper electrode (6) Upper frequency temperature coefficient correction film
The positional relationship between (5) and (6) may be reversed.

以下、図面を参照して、本発明の実施低について説明する。図１は、本発明の実施例を示す正面断面図である。シリコン基板10の表面にSiO2の周波数温度係数補正膜12を800nm形成し、その上にモリブデン（Mo）の下部電極13を300nm、AlNの圧電膜14を2μm、Moの上部電極15を850nm形成し、さらにSiO2の周波数温度係数補正膜16を420nm形成したものである。圧電膜14の振動部の下には空隙11を形成しておく。この例では、空隙11はあらかじめシリコン基板に犠牲層を形成しておき、膜の形成後にその犠牲層の部分を除去することによって形成する。 Hereinafter, implementation of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing an embodiment of the present invention. A SiO 2 frequency temperature coefficient correction film 12 is formed on the surface of the silicon substrate 10 800 nm, and a molybdenum (Mo) lower electrode 13 is formed thereon, an AlN piezoelectric film 14 is formed 2 μm, and an Mo upper electrode 15 is formed 850 nm. Further, the SiO 2 frequency temperature coefficient correction film 16 is formed to 420 nm. A gap 11 is formed below the vibrating portion of the piezoelectric film 14. In this example, the gap 11 is formed by previously forming a sacrificial layer on the silicon substrate and removing the sacrificial layer portion after the film is formed.

図２は、本発明の他の実施例を示す正面断面図で、基本的な構造、製法はおなじであるが、上部電極と上側の周波数温度係数補正膜の位置関係が逆になったものである。周波数温度係数補正膜の厚みは、圧電膜と音響インピーダンスの差異を補正するために適切な値とすることが望ましいが、一般に
０．４≦上部周波数温度係数補正膜の膜厚／下部周波数温度特性補正膜の膜厚≦１．６
の範囲で有効であることが確認された。図3は本発明による圧電薄膜共振子の特性を示すもので、図６に現れていたスプリアスが消えていることが確認された。 FIG. 2 is a front sectional view showing another embodiment of the present invention. The basic structure and manufacturing method are the same, but the positional relationship between the upper electrode and the upper frequency temperature coefficient correction film is reversed. is there. The thickness of the frequency temperature coefficient correction film is desirably an appropriate value for correcting the difference between the piezoelectric film and the acoustic impedance, but generally 0.4 ≦ the thickness of the upper frequency temperature coefficient correction film / the lower frequency temperature characteristic. Correction film thickness ≦ 1.6
It was confirmed to be effective in the range of. FIG. 3 shows the characteristics of the piezoelectric thin film resonator according to the present invention. It was confirmed that the spurious appearing in FIG. 6 disappeared.

本発明は、高周波帯域で使用される圧電薄膜共振子全般に応用でき、特に高精度の特性が要求される装置に適した素子に有用である。   The present invention can be applied to all piezoelectric thin film resonators used in a high frequency band, and is particularly useful for an element suitable for a device that requires high-accuracy characteristics.

本発明の実施例を示す正面断面図Front sectional view showing an embodiment of the present invention 本発明の他の実施例を示す正面断面図Front sectional view showing another embodiment of the present invention その特性の説明図Illustration of its characteristics 従来の圧電薄膜共振子の正面断面図Front sectional view of a conventional piezoelectric thin film resonator 従来の他の圧電薄膜共振子の正面断面図Front sectional view of another conventional piezoelectric thin film resonator その特性の説明図Illustration of its characteristics

符号の説明Explanation of symbols

10、40：基板
11、41：空隙
12．42：周波数温度係数補正膜
13、43：下部電極
14、44：圧電膜
15、45：上部電極
16：周波数温度係数補正膜 10, 40: Board
11, 41: Air gap
12.42: Frequency temperature coefficient correction film
13, 43: Lower electrode
14, 44: Piezoelectric film
15, 45: Upper electrode
16: Frequency temperature coefficient correction film

Claims (3)

基板に支持されてそこに形成された空隙の上部に電極に挟まれた圧電膜を具えた圧電薄膜共振子において、
基板と下部電極間に第1の周波数温度係数補正膜を具えるとともに、上部電極の表面に第2の周波数温度係数補正膜を具えたことを特徴とする圧電薄膜共振子。 In a piezoelectric thin film resonator comprising a piezoelectric film sandwiched between electrodes on the upper part of a gap formed on a substrate,
A piezoelectric thin film resonator comprising a first frequency temperature coefficient correction film between a substrate and a lower electrode, and a second frequency temperature coefficient correction film on the surface of the upper electrode. 基板に支持されてそこに形成された空隙の上部に電極に挟まれた圧電膜を具えた圧電薄膜共振子において、
基板と下部電極間に第1の周波数温度係数補正膜を具えるとともに、上部電極と圧電膜の間に第2の周波数温度係数補正膜を具えたことを特徴とする圧電薄膜共振子。 In a piezoelectric thin film resonator comprising a piezoelectric film sandwiched between electrodes on the upper part of a gap formed on a substrate,
A piezoelectric thin film resonator comprising a first frequency temperature coefficient correction film between a substrate and a lower electrode, and a second frequency temperature coefficient correction film between the upper electrode and the piezoelectric film. 基板に支持されてそこに形成された空隙の上部に電極に挟まれた圧電膜を具えた圧電薄膜共振子において、
圧電膜を挟んで２つの周波数温度特性補正膜を具えたことを特徴とする圧電薄膜共振子。 In a piezoelectric thin film resonator comprising a piezoelectric film sandwiched between electrodes on the upper part of a gap formed on a substrate,
A piezoelectric thin film resonator comprising two frequency temperature characteristic correction films sandwiching a piezoelectric film.
JP2005177500A 2005-06-17 2005-06-17 Piezoelectric thin-film resonator Pending JP2006352619A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2005177500A JP2006352619A (en) 2005-06-17 2005-06-17 Piezoelectric thin-film resonator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005177500A JP2006352619A (en) 2005-06-17 2005-06-17 Piezoelectric thin-film resonator

Publications (1)

Publication Number Publication Date
JP2006352619A true JP2006352619A (en) 2006-12-28

Family

ID=37647961

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005177500A Pending JP2006352619A (en) 2005-06-17 2005-06-17 Piezoelectric thin-film resonator

Country Status (1)

Country Link
JP (1) JP2006352619A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008166510A (en) * 2006-12-28 2008-07-17 Nippon Dempa Kogyo Co Ltd Piezoelectric vibration piece and piezoelectric vibration device
US20110080233A1 (en) * 2009-10-01 2011-04-07 Stmicroelectronics Sa Method for manufacturing baw resonators on a semiconductor wafer
US8397360B2 (en) 2009-10-01 2013-03-19 Stmicroelectronics Sa Method for manufacturing a monolithic oscillator with bulk acoustic wave (BAW) resonators
JP2018026789A (en) * 2016-08-11 2018-02-15 サムソン エレクトロ−メカニックス カンパニーリミテッド． Acoustic wave filter device and manufacturing method of the same
JP2018110317A (en) * 2016-12-29 2018-07-12 新日本無線株式会社 Bulk elastic wave resonator
US10756670B2 (en) 2016-12-19 2020-08-25 Seiko Epson Corporation Resonator, oscillator, electronic apparatus, and vehicle

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008166510A (en) * 2006-12-28 2008-07-17 Nippon Dempa Kogyo Co Ltd Piezoelectric vibration piece and piezoelectric vibration device
US7579762B2 (en) * 2006-12-28 2009-08-25 Nihon Dempa Kogyo Co., Ltd. Piezoelectric vibrating piece and piezoelectric vibrating device
US20110080233A1 (en) * 2009-10-01 2011-04-07 Stmicroelectronics Sa Method for manufacturing baw resonators on a semiconductor wafer
US8397360B2 (en) 2009-10-01 2013-03-19 Stmicroelectronics Sa Method for manufacturing a monolithic oscillator with bulk acoustic wave (BAW) resonators
US9647625B2 (en) 2009-10-01 2017-05-09 Stmicroelectronics Sa Method for manufacturing BAW resonators on a semiconductor wafer
JP2018026789A (en) * 2016-08-11 2018-02-15 サムソン エレクトロ−メカニックス カンパニーリミテッド． Acoustic wave filter device and manufacturing method of the same
CN107733392A (en) * 2016-08-11 2018-02-23 三星电机株式会社 bulk acoustic wave filter device and method for manufacturing the same
US10298197B2 (en) 2016-08-11 2019-05-21 Samsung Electro-Mechanics Co., Ltd. Bulk acoustic wave resonator and method of manufacturing the same
CN107733392B (en) * 2016-08-11 2021-03-12 三星电机株式会社 Bulk acoustic wave resonator and method for manufacturing the same
US10756670B2 (en) 2016-12-19 2020-08-25 Seiko Epson Corporation Resonator, oscillator, electronic apparatus, and vehicle
JP2018110317A (en) * 2016-12-29 2018-07-12 新日本無線株式会社 Bulk elastic wave resonator

Similar Documents

Publication Publication Date Title
JP4685832B2 (en) Resonator and manufacturing method thereof
US20110001394A1 (en) Piezoelectric thin-film tuning fork resonator
WO2004013893B1 (en) Piezo electric on seminconductor on- insulator resonator
JP2006352619A (en) Piezoelectric thin-film resonator
JP6756991B2 (en) Piezoelectric MEMS resonator with high Q value
JPWO2007088696A1 (en) Piezoelectric vibration device
JP2010028536A (en) Tuning fork type vibrator and oscillator
JP2008236439A (en) Quartz oscillating piece
US8319404B2 (en) Surface-mountable quartz-crystal devices and methods for manufacturing same
US20160322954A1 (en) Mems device
WO2018135178A1 (en) Piezoelectric element and resonator using piezoelectric element
WO2004088840A1 (en) Piezoelectric thin film device and method of producing the same
JP2007243435A (en) Piezoelectric resonator chip and frequency adjustment method for same
JP2009111623A (en) Piezoelectric vibrating device
JP2000223992A (en) Piezoelectric vibrator and manufacture therefor
JP2002076824A (en) Piezoelectric thin film resonator, filter and electronic device
US9159902B2 (en) Resonator
JP2007088691A (en) Piezoelectric vibration chip, piezoelectric device, and manufacturing method of them
JP2005033775A5 (en)
JP2008301111A (en) Edge mode piezoelectric vibration chip and frequency adjustment method thereof
JP2007028580A (en) Piezoelectric oscillating piece, piezoelectric oscillator, and frequency adjustment method for piezoelectric oscillating piece
JP4599231B2 (en) Quartz crystal manufacturing method and crystal resonator
JP2008022408A (en) Piezoelectric thin film resonator
JP2008277964A (en) Thin film piezoelectric resonator and manufacturing method thereof
JP2008042431A (en) Piezoelectric vibrator, and its manufacturing method