JP2010048696A - Surface elastic wave type gas sensor - Google Patents

Surface elastic wave type gas sensor Download PDF

Info

Publication number
JP2010048696A
JP2010048696A JP2008213830A JP2008213830A JP2010048696A JP 2010048696 A JP2010048696 A JP 2010048696A JP 2008213830 A JP2008213830 A JP 2008213830A JP 2008213830 A JP2008213830 A JP 2008213830A JP 2010048696 A JP2010048696 A JP 2010048696A
Authority
JP
Japan
Prior art keywords
gas sensor
surface acoustic
acoustic wave
comb
wave type
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.)
Withdrawn
Application number
JP2008213830A
Other languages
Japanese (ja)
Inventor
Junichi Hayasaka
淳一 早坂
Chieko Fujiwara
千恵子 藤原
Yuichi Togano
祐一 戸叶
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.)
Tokin Corp
Original Assignee
NEC Tokin Corp
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 NEC Tokin Corp filed Critical NEC Tokin Corp
Priority to JP2008213830A priority Critical patent/JP2010048696A/en
Publication of JP2010048696A publication Critical patent/JP2010048696A/en
Withdrawn legal-status Critical Current

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly-sensitive surface elastic wave type gas sensor having a structure wherein a sensitive film is not formed on an interdigital electrode or on a propagation domain between the interdigital electrode. <P>SOLUTION: The interdigital electrode 11 comprises a material whose electric resistance is increased by being chemically reacted with detection object gas. The interdigital electrode 11 comprises Ag or Cu, and the detection object gas is hydrogen sulfide. Since having a structure wherein a sensitive film is not formed on the interdigital electrode or on the propagation domain between the interdigital electrode, a more highly-sensitive surface elastic wave type gas sensor can be realized. In addition, selectivity to hydrogen sulfide can be heightened by forming the interdigital electrode from Ag or Cu. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、気体などのガス種や濃度を検知するための表面弾性波型ガスセンサに関するものである。   The present invention relates to a surface acoustic wave type gas sensor for detecting a gas type such as gas and its concentration.

従来の表面弾性波型ガスセンサの一例が特許文献１に開示されている。このセンサは、表面弾性波を励振させるための櫛歯電極上に感応膜(フタロシアニン)を形成しており、感応膜へのガス吸着、例えば窒素酸化物（ＮＯX）に伴う電気特性の変化を発振周波数の変化に変換して検出するものである。 An example of a conventional surface acoustic wave type gas sensor is disclosed in Patent Document 1. In this sensor, a sensitive film (phthalocyanine) is formed on a comb electrode for exciting surface acoustic waves, and the change in electrical characteristics due to gas adsorption to the sensitive film, for example, nitrogen oxide (NO x ), is observed. This is detected by converting to a change in oscillation frequency.

一方、特許文献２には、櫛歯電極対の間にパラジウムと銀の合金薄膜からなる反応膜を形成し、ガス吸着による反応膜の重量変化(質量負荷効果)を利用する表面弾性波型ガスセンサが開示されている。更に、特許文献３では、質量負荷効果を利用したガスセンサの感度を向上させるために、実行的に長い表面弾性波の行路長を設けたセンサ構造が開示されている。   On the other hand, in Patent Document 2, a surface acoustic wave type gas sensor using a reaction film made of an alloy thin film of palladium and silver formed between comb electrode pairs and utilizing a change in weight (mass load effect) of the reaction film due to gas adsorption. Is disclosed. Further, Patent Document 3 discloses a sensor structure provided with a practically long path length of surface acoustic waves in order to improve the sensitivity of the gas sensor utilizing the mass load effect.

特開平８−２２００３９号公報JP-A-8-220039 特開２００６−２２０５０８号公報JP 2006-220508 A 特開２００５−２６５４２３号公報JP 2005-265423 A

以上、従来の表面弾性波型ガスセンサは、いずれのセンサにおいても、感応膜の電気特性の変化による電極間の抵抗の変化を利用しており、構造上、櫛歯電極上や櫛歯電極間の伝搬領域上に感応膜を必要とするために、感応膜の膜圧が厚くなりやすい構造のため感応膜自体の付加によって重量増加による機械エネルギーロスが増加し、表面弾性波の本来の電気機械結合係数ｋ2が低下することになり、それ故に、より高感度な表面弾性波型ガスセンサの実現が困難といった課題があった。 As described above, the conventional surface acoustic wave type gas sensor uses the change in resistance between the electrodes due to the change in the electrical characteristics of the sensitive film in any sensor. Since a sensitive membrane is required on the propagation area, the membrane pressure of the sensitive membrane tends to increase, so the addition of the sensitive membrane increases the mechanical energy loss due to weight increase, and the original electromechanical coupling of surface acoustic waves As a result, the coefficient k 2 is lowered, and therefore there is a problem that it is difficult to realize a surface acoustic wave type gas sensor with higher sensitivity.

本発明の技術的課題は、櫛歯電極上や櫛歯電極間の伝搬領域上に感応膜を形成しない構造を有する高感度な表面弾性波型ガスセンサを提供することにある。   The technical problem of the present invention is to provide a highly sensitive surface acoustic wave type gas sensor having a structure in which a sensitive film is not formed on a comb-tooth electrode or a propagation region between comb-tooth electrodes.

本発明は、櫛歯電極上や櫛歯電極間の伝搬領域上に感応膜を形成しない構造を成すために、より高感度な表面弾性波型ガスセンサが実現される構造である。加えて、櫛歯電極をＡｇあるいはＣｕで形成することで、硫化水素ガスに対する選択性を高めるように構成する。   The present invention is a structure in which a more sensitive surface acoustic wave gas sensor is realized in order to form a structure in which a sensitive film is not formed on the comb-tooth electrodes or on the propagation region between the comb-tooth electrodes. In addition, the comb-teeth electrode is formed of Ag or Cu, so that the selectivity to hydrogen sulfide gas is increased.

本発明によれば、圧電基板上に形成された櫛歯電極から成る表面弾性波型ガスセンサであって、前記櫛歯電極は、検知対象ガスと化学反応することで電気抵抗が増加する材質から成ることを特徴とする表面弾性波型ガスセンサが得られる。   According to the present invention, there is provided a surface acoustic wave type gas sensor including a comb-shaped electrode formed on a piezoelectric substrate, and the comb-shaped electrode is made of a material whose electrical resistance is increased by a chemical reaction with a detection target gas. Thus, a surface acoustic wave type gas sensor can be obtained.

本発明によれば、圧電基板上に形成された第１の櫛歯電極と、第２の櫛歯電極から成る表面弾性波型ガスセンサであって、前記第１の櫛歯電極あるいは第２の櫛歯電極は、検知対象ガスと化学反応することで電気抵抗が増加する材質から成ることを特徴とする表面弾性波型ガスセンサ得られる。   According to the present invention, there is provided a surface acoustic wave type gas sensor comprising a first comb electrode and a second comb electrode formed on a piezoelectric substrate, wherein the first comb electrode or the second comb is used. The tooth electrode can be obtained from a surface acoustic wave type gas sensor characterized in that it is made of a material whose electric resistance is increased by a chemical reaction with the detection target gas.

本発明によれば、前記櫛歯電極は、ＡｇあるいはＣｕから成り、検知対象ガスが硫化水素であることを特徴とする表面弾性波型ガスセンサが得られる。   According to the present invention, there is obtained a surface acoustic wave type gas sensor characterized in that the comb electrode is made of Ag or Cu, and the detection target gas is hydrogen sulfide.

本発明によれば、前記櫛歯電極は、前記圧電基板上に形成された検知対象ガスに対して化学的に安定で且つ電気抵抗が常に一定の導電層と、該導電層上に積層された検知対象ガスと化学反応することで電気抵抗が増加する反応層から成ることを特徴とする表面弾性波型ガスセンサが得られる。   According to the present invention, the comb electrode is laminated on the conductive layer, and a conductive layer that is chemically stable with respect to the detection target gas formed on the piezoelectric substrate and has a constant electrical resistance. A surface acoustic wave type gas sensor characterized by comprising a reaction layer whose electrical resistance increases by chemically reacting with the detection target gas can be obtained.

本発明によれば、前記導電層はＡｕから成り、前記反応層はＡｇあるいはＣｕから成り、検知対象ガスは硫化水素であることを特徴とする表面弾性波型ガスセンサが得られる。   According to the present invention, there can be obtained a surface acoustic wave gas sensor characterized in that the conductive layer is made of Au, the reaction layer is made of Ag or Cu, and the detection target gas is hydrogen sulfide.

本発明のガスセンサにおいては、櫛歯電極上や櫛歯電極間の伝搬領域上に感応膜を形成しない構造を成すために、より高感度な表面弾性波型ガスセンサが実現される。加えて、櫛歯電極をＡｇあるいはＣｕで形成することで、硫化水素ガスに対する選択性を高めることが可能となる。   In the gas sensor of the present invention, since a sensitive film is not formed on the comb-tooth electrodes or on the propagation region between the comb-tooth electrodes, a surface acoustic wave gas sensor with higher sensitivity is realized. In addition, it is possible to increase the selectivity for the hydrogen sulfide gas by forming the comb electrode with Ag or Cu.

以下、本発明における表面弾性波型ガスセンサについて図面を参照しながら詳細に説明する。   Hereinafter, a surface acoustic wave type gas sensor according to the present invention will be described in detail with reference to the drawings.

（実施の形態１）
図１は、本発明の第一の表面弾性波型ガスセンサの構成図を示す。図１（ａ）は上面図、図１（ｂ）はａ−ａ'切断面の断面図。本実施の形態１の表面弾性波型ガスセンサは、圧電性を有する圧電基板１２上に公知の薄膜形成技術によって形成された櫛歯電極１１からガスセンサ素子１３が構成されている。尚、この櫛歯電極１１は、検知対象ガスとの化学反応によって、その電気抵抗が増加する材質から形成されている。櫛歯電極１１の共振周波数をインピーダンスアナライザー等により測定して、検知対象ガスにより変化した櫛歯電極１１の共振周波数の変動を測定する。 (Embodiment 1)
FIG. 1 shows a configuration diagram of a first surface acoustic wave type gas sensor of the present invention. 1A is a top view, and FIG. 1B is a cross-sectional view taken along the line aa ′. In the surface acoustic wave type gas sensor according to the first embodiment, a gas sensor element 13 is composed of comb-shaped electrodes 11 formed on a piezoelectric substrate 12 having piezoelectricity by a known thin film forming technique. The comb electrode 11 is made of a material whose electrical resistance increases due to a chemical reaction with the detection target gas. The resonance frequency of the comb electrode 11 is measured by an impedance analyzer or the like, and the fluctuation of the resonance frequency of the comb electrode 11 changed by the detection target gas is measured.

図２は、本発明の表面弾性波型ガスセンサ櫛歯電極断面の拡大図示す。例えば、圧電基板２３上に、銀（Ａｇ）薄膜で形成された櫛歯電極２１は、硫化水素（Ｈ2Ｓ）に触れることによって、下記の式（１）に従がって、電極表面から高抵抗層２２の硫化銀（Ａｇ2Ｓ）に変化する。 FIG. 2 is an enlarged view of a surface acoustic wave type gas sensor comb electrode cross section of the present invention. For example, the comb-tooth electrode 21 formed of a silver (Ag) thin film on the piezoelectric substrate 23 comes into contact with hydrogen sulfide (H 2 S), and from the electrode surface according to the following formula (1). The high resistance layer 22 is changed to silver sulfide (Ag 2 S).

４Ａｇ＋２Ｈ2Ｓ＋Ｏ2 → ２Ａｇ2Ｓ＋２Ｈ2Ｏ ・・・・・・（１） 4Ag + 2H 2 S + O 2 → 2Ag 2 S + 2H 2 O (1)

この硫化銀の電気抵抗は、銀に比べて数桁高い性質を有する。従がって、Ａｇからなる櫛歯電極の表面が上記の硫化反応によってＡｇ2Ｓに変化することで、高抵抗層２２が形成され電気抵抗が増加するため、実効的な電気機械結合係数ｋ2が減少し、表面弾性波の共振周波数や振幅が変化する。この効果を積極的に利用することで高感度な化学センサが実現できる。加えて、表面弾性波は、１０ＭＨｚ以上の高周波帯で駆動されるため、表皮効果による金属導体表面の電気抵抗に大きく影響を受けるので、本発明の化学センサは原理上、高感度化に好適である。 The electrical resistance of silver sulfide has a property that is several orders of magnitude higher than that of silver. Therefore, since the surface of the comb-shaped electrode made of Ag is changed to Ag 2 S by the above sulfurization reaction, the high resistance layer 22 is formed and the electric resistance is increased. Therefore, the effective electromechanical coupling coefficient k 2 decreases, and the resonant frequency and amplitude of the surface acoustic wave change. By actively using this effect, a highly sensitive chemical sensor can be realized. In addition, since the surface acoustic wave is driven in a high frequency band of 10 MHz or more, it is greatly affected by the electric resistance of the metal conductor surface due to the skin effect, and therefore the chemical sensor of the present invention is suitable for high sensitivity in principle. is there.

具体的には、圧電基板としてタンタル酸リチウム（ＬｉＴａＯ3）基板上に、公知のマグネトロンスパッタ装置により厚み１，２００Åの銀（Ａｇ）薄膜を形成し、その後、フォトリソ技術により櫛歯電極の幅とギャップを各々３μｍとした表面弾性波型ガスセンサを製作した。この場合の共振周波数は、約３３０ＭＨｚであった。また、製作したセンサの発振周波数は、硫化水素（Ｈ2Ｓ）１００ｐｐｍに対して約１ＭＨｚの周波数変動が確認され、約１×１０-4ｐｐｍ／Ｈｚの高い感度を有する表面弾性波型ガスセンサが実現できた。櫛歯電極の材質としては、Ａｇの代わりにＣｕを用いても同様の効果が期待できる。 Specifically, a silver (Ag) thin film having a thickness of 1,200 mm is formed on a lithium tantalate (LiTaO 3 ) substrate as a piezoelectric substrate by a known magnetron sputtering apparatus, and then the width of the comb electrode is determined by photolithography. Surface acoustic wave type gas sensors with gaps of 3 μm were manufactured. In this case, the resonance frequency was about 330 MHz. Moreover, the oscillation frequency of the manufactured sensor was confirmed to be about 1 MHz with respect to 100 ppm of hydrogen sulfide (H 2 S), and a surface acoustic wave type gas sensor having a high sensitivity of about 1 × 10 −4 ppm / Hz was obtained. Realized. The same effect can be expected even when Cu is used instead of Ag as the material of the comb electrode.

(実施の形態２)
図３は、本発明の第二の表面弾性波型ガスセンサの構成図を示す。図３（ａ）は上面図、図３（ｂ）はａ−ａ'切断面の断面図。本実施の形態２の表面弾性波型ガスセンサは、圧電基板３２上に形成された第１の櫛歯電極３１と、第２の櫛歯電極３３からガスセンサ素子３４が構成されている。尚、実施の形態１と同様に、前記第１の櫛歯電極３１あるいは第２の櫛歯電極３３は、検知対象ガスと化学反応することで電気抵抗が増加する材質から形成されている。 (Embodiment 2)
FIG. 3 shows a configuration diagram of the second surface acoustic wave type gas sensor of the present invention. 3A is a top view, and FIG. 3B is a cross-sectional view taken along the line aa ′. In the surface acoustic wave type gas sensor according to the second embodiment, a gas sensor element 34 is composed of a first comb electrode 31 and a second comb electrode 33 formed on the piezoelectric substrate 32. As in the first embodiment, the first comb-teeth electrode 31 or the second comb-teeth electrode 33 is made of a material whose electrical resistance increases by a chemical reaction with the detection target gas.

前述と同様の原理で、検知対象ガスにより、第１の櫛歯電極３１と第２の櫛歯電極３３の高抵抗層２２の電気抵抗が増加して、第１の櫛歯電極３１の励振周波数が変化し、前記第１の櫛歯電極３１からの表面弾性波を、高抵抗層２２の電気抵抗が変化した第２の櫛歯電極３３で、前記第１の櫛歯電極３１の表面弾性波を受信し、前記第２の櫛歯電極３３の共振周波数変化をインピーダンスアナライザー等により共振周波数の変化として検出することによって、伝送型構成のガスセンサを実現することができる。   Based on the same principle as described above, the electric resistance of the high resistance layer 22 of the first comb electrode 31 and the second comb electrode 33 is increased by the detection target gas, and the excitation frequency of the first comb electrode 31 is increased. The surface acoustic wave from the first comb-tooth electrode 31 is converted into the surface acoustic wave of the first comb-tooth electrode 31 by the second comb-tooth electrode 33 in which the electric resistance of the high resistance layer 22 is changed. , And detecting a change in resonance frequency of the second comb electrode 33 as a change in resonance frequency by an impedance analyzer or the like, a transmission type gas sensor can be realized.

また、第１の櫛歯電極３１の共振周波数を基準として、前述と同様の原理で、検知対象ガスにより第２の櫛歯電極３３の高抵抗層２２の電気抵抗が増加し、変化した第２の櫛歯電極３３の共振周波数をインピーダンスアナライザー等により測定し、第１の櫛歯電極３１の測定した共振周波数と比較することによって、温度、ノイズ等の変化に対して安定した測定値を検出することができる伝送型構成のガスセンサも実現することができる。   Further, based on the resonance frequency of the first comb electrode 31, the electric resistance of the high resistance layer 22 of the second comb electrode 33 is increased and changed by the detection target gas on the same principle as described above. By measuring the resonance frequency of the first comb-teeth electrode 33 using an impedance analyzer or the like and comparing it with the resonance frequency measured by the first comb-teeth electrode 31, a stable measurement value is detected against changes in temperature, noise, and the like. It is also possible to realize a gas sensor having a transmission configuration that can be used.

具体的には、圧電基板としてタンタル酸リチウム（ＬｉＴａＯ3）基板上に、公知のマグネトロンスパッタ装置により厚み１，２００Åの銀（Ａｇ）薄膜を形成し、その後、フォトリソ技術により第１の櫛歯電極と第２の櫛歯電極の幅とギャップを各々３μｍとし、第１の櫛歯電極と第２の櫛葉電極との電極間隔を約６００μｍとした伝送型構成の表面弾性波型ガスセンサを製作した。この場合の共振周波数は、約３３０ＭＨｚであった。また、製作したセンサの発振周波数は、硫化水素（Ｈ2Ｓ）１００ｐｐｍに対して約０．１ＭＨｚの周波数変動が確認され、約１×１０-3ｐｐｍ／Ｈｚの高い感度を有する伝送型構成の表面弾性波型ガスセンサが実現できた。櫛歯電極の材質としては、Ａｇの代わりにＣｕを用いても同様の効果が期待できる。 Specifically, a silver (Ag) thin film having a thickness of 1,200 mm is formed on a lithium tantalate (LiTaO 3 ) substrate as a piezoelectric substrate by a known magnetron sputtering apparatus, and then the first comb electrode is formed by photolithography. A surface acoustic wave type gas sensor having a transmission type configuration in which the width and gap of each of the first and second comb-teeth electrodes is 3 μm and the electrode interval between the first and second comb-teeth electrodes is about 600 μm is manufactured. . In this case, the resonance frequency was about 330 MHz. In addition, the oscillation frequency of the manufactured sensor is confirmed to be about 0.1 MHz with respect to 100 ppm of hydrogen sulfide (H 2 S), and the transmission type configuration has a high sensitivity of about 1 × 10 −3 ppm / Hz. A surface acoustic wave type gas sensor has been realized. The same effect can be expected even when Cu is used instead of Ag as the material of the comb electrode.

(実施の形態３)
図４は、本発明の表面弾性波型ガスセンサ櫛歯電極断面の拡大図示す。全体構成は、前述の実施の形態１、２で示したものと同様である。この櫛歯電極は、圧電基板４５上に導電層４４と反応層４３が積層化され櫛歯電極４１が構成されている。尚、導電層４４は検知対象ガスに対して化学的、電気的に常に安定であり、反応層４３は実施の形態１、２と同様に検知対象ガスと化学反応することで電気抵抗が増加する材質から形成されており、反応して高抵抗層４２が形成される。このような積層構造をとることによって、検知対象ガスによる櫛歯電極の化学反応を導電層４４で止めることができ、例えば、反応層には金（Ａｕ）、導電層には銀（Ａｇ）を用いることが、検知対象ガス硫化水素（Ｈ2Ｓ）に対しては好適である。これにより、精度良く検知対象ガスを検出することが可能になる。 (Embodiment 3)
FIG. 4 is an enlarged view of a cross section of a surface acoustic wave type gas sensor comb electrode according to the present invention. The overall configuration is the same as that shown in the first and second embodiments. In this comb electrode, a conductive electrode 44 and a reaction layer 43 are laminated on a piezoelectric substrate 45 to form a comb electrode 41. The conductive layer 44 is always chemically and electrically stable with respect to the detection target gas, and the reaction layer 43 increases in electrical resistance by chemically reacting with the detection target gas as in the first and second embodiments. The high resistance layer 42 is formed by reaction. By adopting such a laminated structure, the chemical reaction of the comb-teeth electrode due to the detection target gas can be stopped by the conductive layer 44. For example, gold (Au) is used for the reaction layer and silver (Ag) is used for the conductive layer. The use is suitable for the detection target gas hydrogen sulfide (H 2 S). This makes it possible to detect the detection target gas with high accuracy.

具体的には、前述同様に、圧電基板としてタンタル酸リチウム（ＬｉＴａＯ3）基板上に、公知のマグネトロンスパッタ装置により、厚み７００Åの金（Ａｕ）、厚み１，２００Åの銀（Ａｇ）薄膜を形成し、その後、フォトリソ技術により櫛歯電極の幅とギャップを各々３μｍとした表面弾性波型ガスセンサを製作した。この場合の共振周波数は、約３３０ＭＨｚであった。また、製作したセンサの発振周波数は、硫化水素（Ｈ2Ｓ）１００ｐｐｍに対して約０．８ＭＨｚの周波数変動が確認され、約１×１０-3ｐｐｍ／Ｈｚの前述と同様に高い感度を有する表面弾性波型ガスセンサが実現できた。また、櫛歯電極の材質としては、Ａｇの代わりにＣｕを用いても同様の効果が期待できる。 Specifically, as described above, a gold (Au) film having a thickness of 700 mm and a silver (Ag) film having a thickness of 1,200 mm are formed on a lithium tantalate (LiTaO 3 ) substrate as a piezoelectric substrate by a known magnetron sputtering apparatus. Thereafter, a surface acoustic wave type gas sensor having a comb electrode width and a gap of 3 μm was manufactured by photolithography. In this case, the resonance frequency was about 330 MHz. In addition, the oscillation frequency of the manufactured sensor is confirmed to have a frequency fluctuation of about 0.8 MHz with respect to 100 ppm of hydrogen sulfide (H 2 S), and has a high sensitivity as described above of about 1 × 10 −3 ppm / Hz. A surface acoustic wave type gas sensor was realized. The same effect can be expected even when Cu is used instead of Ag as the material of the comb-tooth electrode.

また、同様に伝送型構成の表面弾性波型ガスセンサを製作した時は、共振周波数は、約３１０ＭＨｚであった。また、製作したセンサの発振周波数は、硫化水素（Ｈ2Ｓ）１００ｐｐｍに対して約０．２ＭＨｚの周波数変動が確認され、約５×１０-4ｐｐｍ／Ｈｚの前述と同様に高い感度を有する表面弾性波型ガスセンサが実現できた。また、櫛歯電極の材質としては、Ａｇの代わりにＣｕを用いても同様の効果が期待できる。 Similarly, when a surface acoustic wave type gas sensor having a transmission configuration was manufactured, the resonance frequency was about 310 MHz. The oscillation frequency of the manufactured sensor is confirmed to be about 0.2 MHz with respect to 100 ppm of hydrogen sulfide (H 2 S), and has a high sensitivity as described above of about 5 × 10 −4 ppm / Hz. A surface acoustic wave type gas sensor has been realized. The same effect can be expected even when Cu is used instead of Ag as the material of the comb-tooth electrode.

以上、説明した実効的な電気機械結合係数ｋ2は、一般的に櫛歯電極の種類と膜厚とに関係し、最大値をとる条件がある。本発明で提案するガスセンサでは、圧電基板とその上に形成される櫛歯電極の種類、膜厚との関係において、ｋ2が最大値をとる条件に設計することが望ましい。 The effective electromechanical coupling coefficient k 2 described above is generally related to the type of comb electrode and the film thickness, and has a maximum value. In the gas sensor proposed in the present invention, it is desirable to design under the condition that k 2 takes the maximum value in the relationship between the piezoelectric substrate and the type and film thickness of the comb electrode formed thereon.

以上、この発明の実施の形態を説明したが、この発明は、これらの実施の形態に限られるものではなく、この発明の要旨を逸脱しない範囲の設計変更があっても本発明に含まれる。すなわち、当業者であれば、当然成しえるであろう各種変形、修正もまた本発明に含まれる。   As mentioned above, although embodiment of this invention was described, this invention is not restricted to these embodiment, Even if there is a design change of the range which does not deviate from the summary of this invention, it is included in this invention. That is, various modifications and corrections that can naturally be made by those skilled in the art are also included in the present invention.

本発明の表面弾性波型ガスセンサを用いることにより、ガス濃度やガスの種類を高感度に検出するシステムを構築することができる。   By using the surface acoustic wave type gas sensor of the present invention, it is possible to construct a system for detecting gas concentration and gas type with high sensitivity.

本発明第一の表面弾性波型ガスセンサの構成図、図１（ａ）は上面図、図１（ｂ）はａ−ａ'切断面の断面図。BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the 1st surface acoustic wave type gas sensor of this invention, FIG. 1 (a) is a top view, FIG.1 (b) is sectional drawing of aa 'cut surface. 本発明の表面弾性波型ガスセンサ櫛歯電極断面の拡大図。The enlarged view of the surface acoustic wave type gas sensor comb electrode cross section of this invention. 本発明の第二の表面弾性波型ガスセンサの構成図、図３（ａ）は上面図、図３（ｂ）はａ−ａ'切断面の断面図。The block diagram of the 2nd surface acoustic wave type gas sensor of this invention, Fig.3 (a) is a top view, FIG.3 (b) is sectional drawing of aa 'cut surface. 本発明の表面弾性波型ガスセンサ櫛歯電極断面の拡大図。The enlarged view of the surface acoustic wave type gas sensor comb electrode cross section of this invention.

符号の説明Explanation of symbols

１１ 櫛歯電極
１２ 圧電基板
１３ ガスセンサ素子
２１ 櫛歯電極
２２ 高抵抗層
２３ 圧電基板
３１ 第１の櫛歯電極
３２ 圧電基板
３３ 第２の櫛歯電極
３４ ガスセンサ素子
４１ 櫛歯電極
４２ 高抵抗層
４３ 反応層
４４ 導電層
４５ 圧電基板 11 Comb electrode 12 Piezoelectric substrate 13 Gas sensor element 21 Comb electrode 22 High resistance layer 23 Piezoelectric substrate 31 First comb electrode 32 Piezoelectric substrate 33 Second comb electrode 34 Gas sensor element 41 Comb electrode 42 High resistance layer 43 Reaction layer 44 Conductive layer 45 Piezoelectric substrate

Claims (5)

圧電基板上に形成された櫛歯電極から成る表面弾性波型ガスセンサであって、
前記櫛歯電極は、検知対象ガスと化学反応することで電気抵抗が増加する材質から成ることを特徴とする表面弾性波型ガスセンサ。 A surface acoustic wave type gas sensor composed of comb-shaped electrodes formed on a piezoelectric substrate,
The surface acoustic wave type gas sensor according to claim 1, wherein the comb electrode is made of a material whose electrical resistance is increased by a chemical reaction with a gas to be detected. 圧電基板上に形成された第１の櫛歯電極と、第２の櫛歯電極から成る表面弾性波型ガスセンサであって、
前記第１の櫛歯電極あるいは前記第２櫛歯電極は、検知対象ガスと化学反応することで電気抵抗が増加する材質から成ることを特徴とする表面弾性波型ガスセンサ。 A surface acoustic wave type gas sensor comprising a first comb electrode and a second comb electrode formed on a piezoelectric substrate,
The surface acoustic wave type gas sensor according to claim 1, wherein the first comb-tooth electrode or the second comb-tooth electrode is made of a material whose electrical resistance is increased by a chemical reaction with a detection target gas. 請求項１あるいは請求項２に記載の表面弾性波型ガスセンサにおいて、前記櫛歯電極はＡｇあるいはＣｕから成り、検知対象ガスが硫化水素であることを特徴とする表面弾性波型ガスセンサ。   3. The surface acoustic wave gas sensor according to claim 1, wherein the comb electrode is made of Ag or Cu, and the detection target gas is hydrogen sulfide. 請求項１あるいは請求項２に記載の表面弾性波型ガスセンサであって、前記櫛歯電極は、前記圧電基板上に形成された検知対象ガスに対して化学的に安定で且つ電気抵抗が常に一定の導電層と、該導電層上に積層された検知対象ガスと化学反応することで電気抵抗が増加する反応層から成ることを特徴とする表面弾性波型ガスセンサ。   3. The surface acoustic wave type gas sensor according to claim 1, wherein the comb electrode is chemically stable with respect to a detection target gas formed on the piezoelectric substrate and has an electric resistance that is always constant. A surface acoustic wave type gas sensor comprising: a conductive layer, and a reaction layer whose electrical resistance is increased by a chemical reaction with a detection target gas laminated on the conductive layer. 請求項４に記載の表面弾性波型ガスセンサにおいて、前記導電層はＡｕから成り、前記反応層はＡｇあるいはＣｕから成り、検知対象ガスは硫化水素であることを特徴とする表面弾性波型ガスセンサ。   5. The surface acoustic wave gas sensor according to claim 4, wherein the conductive layer is made of Au, the reaction layer is made of Ag or Cu, and the detection target gas is hydrogen sulfide.
JP2008213830A 2008-08-22 2008-08-22 Surface elastic wave type gas sensor Withdrawn JP2010048696A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2008213830A JP2010048696A (en) 2008-08-22 2008-08-22 Surface elastic wave type gas sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2008213830A JP2010048696A (en) 2008-08-22 2008-08-22 Surface elastic wave type gas sensor

Publications (1)

Publication Number Publication Date
JP2010048696A true JP2010048696A (en) 2010-03-04

Family

ID=42065894

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2008213830A Withdrawn JP2010048696A (en) 2008-08-22 2008-08-22 Surface elastic wave type gas sensor

Country Status (1)

Country Link
JP (1) JP2010048696A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102768230A (en) * 2012-08-09 2012-11-07 电子科技大学 Vertical flat plate capacitive gas sensor and preparation method thereof
KR20210054744A (en) 2019-11-06 2021-05-14 한국생산기술연구원 hydrogen sulfide sensor based on discoloration and the manufacturing method thereof
KR20220067023A (en) 2020-11-17 2022-05-24 한국생산기술연구원 washable color- changing H2S sensor and the manufacturing method thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102768230A (en) * 2012-08-09 2012-11-07 电子科技大学 Vertical flat plate capacitive gas sensor and preparation method thereof
CN102768230B (en) * 2012-08-09 2014-03-19 电子科技大学 Vertical flat plate capacitive gas sensor and preparation method thereof
KR20210054744A (en) 2019-11-06 2021-05-14 한국생산기술연구원 hydrogen sulfide sensor based on discoloration and the manufacturing method thereof
KR20220067023A (en) 2020-11-17 2022-05-24 한국생산기술연구원 washable color- changing H2S sensor and the manufacturing method thereof

Similar Documents

Publication Publication Date Title
US9322809B2 (en) Elastic wave sensor
US9160299B2 (en) Acoustic wave element and acoustic wave element sensor
US6378370B1 (en) Temperature compensated surface-launched acoustic wave sensor
US20060254356A1 (en) Wireless and passive acoustic wave liquid conductivity sensor
KR101776089B1 (en) Surface acoustic wave sensor system and measurement method using multiple-transit-echo wave
US20060132000A1 (en) Piezoelectric device, its manufacturing method, and touch panel device
KR20070120602A (en) Wireless acoustic oil filter sensor
US20120068690A1 (en) Bulk acoustic wave resonator sensor
US20060272415A1 (en) Deep-fry oil quality sensor
JP2007010378A (en) Surface acoustic wave element, its manufacturing method, surface acoustic wave sensor and surface acoustic wave sensor system
US8207650B2 (en) Surface acoustic wave sensor
WO2006138640A1 (en) Passive and wireless acoustic wave accelerometer
KR101711204B1 (en) Single-input Multi-output Surface Acoustic Wave Device
JP5087964B2 (en) Wireless surface acoustic wave sensor
JP2006184011A (en) Surface acoustic wave sensor
JP2010048696A (en) Surface elastic wave type gas sensor
US7075216B1 (en) Lateral field excited acoustic wave sensor
JP2006220508A (en) Gas sensor
JP2005121498A (en) Surface acoustic sensing system
JP2005214713A (en) Humidity state detection system
JP2000214140A (en) Sensor
US20110133599A1 (en) Surface acoustic wave sensor
JP2008180668A (en) Lamb wave type high-frequency sensor device
JP7351508B2 (en) Recognition signal generation element and element recognition system
KR102629642B1 (en) Multi-material Surface Acoustic Wave Measuring Apparatus

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20110708

A761 Written withdrawal of application

Free format text: JAPANESE INTERMEDIATE CODE: A761

Effective date: 20120828