JPH07140102A - Semiconductor gas sensor and method for setting objective gas - Google Patents
Semiconductor gas sensor and method for setting objective gasInfo
- Publication number
- JPH07140102A JPH07140102A JP28937493A JP28937493A JPH07140102A JP H07140102 A JPH07140102 A JP H07140102A JP 28937493 A JP28937493 A JP 28937493A JP 28937493 A JP28937493 A JP 28937493A JP H07140102 A JPH07140102 A JP H07140102A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- electrodes
- semiconductor
- film thickness
- gas sensor
- 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
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 title claims description 5
- 239000000758 substrate Substances 0.000 claims abstract description 11
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 7
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 7
- 238000001514 detection method Methods 0.000 claims description 5
- 239000010408 film Substances 0.000 abstract description 63
- 230000035945 sensitivity Effects 0.000 abstract description 37
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- 239000010409 thin film Substances 0.000 abstract description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 abstract 2
- 230000001143 conditioned effect Effects 0.000 abstract 1
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 abstract 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N zinc oxide Inorganic materials [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 164
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 36
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 24
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 16
- 239000001257 hydrogen Substances 0.000 description 10
- 229910052739 hydrogen Inorganic materials 0.000 description 10
- 239000001282 iso-butane Substances 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 150000002431 hydrogen Chemical class 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 231100000572 poisoning Toxicity 0.000 description 4
- 230000000607 poisoning effect Effects 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002772 conduction electron Substances 0.000 description 1
- 238000010411 cooking Methods 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、半導体式ガスセンサ及
びその検知対象ガスの設定方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor gas sensor and a method for setting a gas to be detected by the semiconductor gas sensor.
【０００２】[0002]
【従来の技術】現在一般に広く市販されている半導体式
可燃性ガスセンサとしては直熱式−焼結体タイプと、傍
熱式−円筒状厚膜タイプの種類がある。一方平板型ガス
センサは、量産性が高く製造コストを安くできるという
メリットが考えられるため、厚膜タイプ、薄膜タイプに
ついて多くの研究が為され、特開昭５２−１５３４９８
号、特開昭５３−７４４９５号、特開昭６３−２２３５
５１号、特開平１−２５０５８５２号等により既に種々
のものが提案されているが、可燃性ガスセンサとして実
用化されたものはなかった。2. Description of the Related Art There are two types of semiconductor-type combustible gas sensors which are currently widely commercially available: a direct heating type-sintered body type and an indirectly heating type-cylindrical thick film type. On the other hand, the flat plate type gas sensor is considered to be advantageous in that it can be mass-produced and can be manufactured at a low cost. Therefore, much research has been conducted on a thick film type and a thin film type.
JP-A-53-74495, JP-A-63-2235
No. 51, JP-A 1-2505852, etc. have already proposed various types, but none have been put into practical use as a flammable gas sensor.
【０００３】[0003]
【発明が解決しようとする課題】つまり従来の平板型ガ
スセンサは、検知対象ガスとなるメタン、ブタン等炭化
水素系ガスに対する感度が小さく、妨害ガス（誤報の原
因）となるアルコールに対する感度が大きいという問題
があった。また希望のガス感度を得るため、例えばアル
コールに対する感度を小さくするために感ガス部の上に
触媒層を設ける等の手段がとられているが、触媒層の経
時変化が大きい等の問題点があった。更に触媒相を設け
る場合工程が煩雑になり、特性ばらつきも大きくなるた
め製造コストが高くなるという問題があった。That is, the conventional flat plate type gas sensor is low in sensitivity to hydrocarbon gases such as methane and butane, which are detection target gases, and high in sensitivity to alcohol, which is an interfering gas (a cause of false alarm). There was a problem. Further, in order to obtain a desired gas sensitivity, for example, in order to reduce the sensitivity to alcohol, a means such as providing a catalyst layer on the gas-sensing portion is taken, but there is a problem that the catalyst layer has a large change over time. there were. Further, when the catalyst phase is provided, the process becomes complicated and the characteristic variation becomes large, resulting in a problem that the manufacturing cost becomes high.
【０００４】しかも従来の平板型ガスセンサは市販され
ている直熱式−焼結体タイプや、傍熱式−円筒状厚膜タ
イプのガスセンサに比べて汚染物質（シリコンスプレ
ー、ＳＯｘ等）による被毒に弱く、連続使用時の経時変
化が大きいという問題があった。本発明は上記の問題点
に鑑みて為されたもので、請求項１の発明、第４の発明
の目的とするところは検知対象のガス種に対する感度を
大きくでき、しかもガス選択性の異なるものを製造する
ことが容易な半導体式ガスセンサ及びその検知対象ガス
設定方法を提供するにある。Moreover, the conventional flat plate type gas sensor is poisoned by pollutants (silicon spray, SOx, etc.) as compared with commercially available direct heating type-sintered body type gas sensor and indirectly heating type-cylindrical thick film type gas sensor. However, there is a problem in that it is weak and changes significantly over time during continuous use. The present invention has been made in view of the above problems, and an object of the inventions of claims 1 and 4 is to increase the sensitivity to the gas species to be detected and to have different gas selectivity. It is an object of the present invention to provide a semiconductor gas sensor that is easy to manufacture and a method of setting a gas to be detected by the semiconductor gas sensor.
【０００５】請求項２の発明の目的とするところは、請
求項１の目的に加えて感ガス部の抵抗のばらつきが少な
く、しかも経時変化が少なく、耐被毒性も高い半導体式
ガスセンサを提供するにある。請求項３の発明の目的と
するところは、特にアルコールのような酸化（燃焼）し
やすいノイズガスの感度を小さくすることができる半導
体式ガスセンサを提供するにある。The object of the invention of claim 2 is, in addition to the object of claim 1, to provide a semiconductor gas sensor in which the variation in resistance of the gas sensing portion is small, the change with time is small, and the poisoning resistance is high. It is in. An object of the invention of claim 3 is to provide a semiconductor gas sensor which can reduce the sensitivity of noise gas which is particularly likely to be oxidized (burned) such as alcohol.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に、請求項１の発明は、ヒータと、一対若しくは複数対
の電極と、これらの電極上に形成した金属酸化物半導体
からなる感ガス部とを平板状の絶縁基板に備えた半導体
式ガスセンサにおいて、対の電極の間隔寸法と感ガス部
の膜厚寸法の相対比率を検知対象ガスに対応させて設定
したものである。In order to achieve the above-mentioned object, the invention of claim 1 is a gas sensitive gas comprising a heater, a pair of electrodes or a plurality of pairs of electrodes, and a metal oxide semiconductor formed on these electrodes. In a semiconductor gas sensor having a plate-shaped insulating substrate on a flat insulating substrate, the relative ratio between the distance between the pair of electrodes and the film thickness of the gas-sensitive portion is set in correspondence with the gas to be detected.
【０００７】請求項２の発明は、請求項１の発明におい
て、感ガス部の膜厚寸法範囲を５０μｍ乃至３００μｍ
としたものである。請求項３の発明は、請求項１の発明
において、対の電極が並行している部位全体を少なくと
も感ガス部で覆ったものである。請求項４の発明は、ヒ
ータと、一対若しくは複数対の電極と、これらの電極上
に形成した金属酸化物半導体からなる感ガス部とを平板
状の絶縁基板に備えた半導体式ガスセンサの対の電極の
間隔寸法と感ガス部の膜厚寸法の相対比率を選定して検
知対象ガスを設定することを特徴とする。According to a second aspect of the present invention, in the first aspect of the invention, the film thickness dimension range of the gas sensing portion is 50 μm to 300 μm.
It is what According to a third aspect of the invention, in the first aspect of the invention, at least the gas-sensitive portion covers at least the entire portion where the pair of electrodes are in parallel. According to a fourth aspect of the present invention, there is provided a pair of semiconductor gas sensors including a heater, a pair of electrodes, or a plurality of pairs of electrodes, and a gas-sensitive portion made of a metal oxide semiconductor formed on these electrodes on a flat insulating substrate. The detection target gas is set by selecting the relative ratio between the electrode spacing and the film thickness of the gas sensitive portion.
【０００８】[0008]
【作用】請求項１の発明によれば、対の電極の間隔寸法
と感ガス部の膜厚寸法の相対比率を検知対象ガスに対応
させて設定したものであるから、感ガス部の膜厚寸法や
電極間隔の寸法を変化させたりするだけで、ガス種に対
する感度を変えることができ、そのため検知対象のガス
種が異なるガスセンサを容易に製造することができる。According to the first aspect of the present invention, the relative ratio of the distance between the pair of electrodes and the film thickness of the gas sensing portion is set in correspondence with the gas to be detected. The sensitivity to the gas species can be changed only by changing the dimension or the dimension of the electrode interval, and therefore, the gas sensor having different gas species to be detected can be easily manufactured.
【０００９】請求項２の発明によれば、感ガス部の膜厚
寸法範囲を５０μｍ乃至３００μｍとしたものであるか
ら、感ガス部の抵抗のばらつきが小さく、しかも連続使
用時の感ガス部の経時的な抵抗値の変化（感度変化）が
小さく、更に汚染物質に対する耐被毒性が高いガスセン
サを実現することができる。更に請求項３の発明によれ
ば、対の電極が並行している部位全体を少なくとも感ガ
ス部で覆ったものであるから、ノイズガスとなるアルコ
ール等のような酸化（燃焼）し易いガスの感度を小さく
することができ、検知対象ガスを確実に検知できるガス
センサを実現することができる。According to the second aspect of the invention, since the film thickness dimension range of the gas sensing portion is 50 μm to 300 μm, the variation in resistance of the gas sensing portion is small, and the gas sensing portion of the gas sensing portion during continuous use is small. It is possible to realize a gas sensor in which the resistance value changes with time (sensitivity change) is small and the poisoning resistance to pollutants is high. Further, according to the third aspect of the invention, since at least the entire area where the pair of electrodes are in parallel is covered with the gas sensitive portion, the sensitivity of a gas such as alcohol that becomes noise gas that easily oxidizes (burns). Can be reduced, and a gas sensor that can reliably detect the gas to be detected can be realized.
【００１０】更にまた請求項４の発明によれば、対の電
極の間隔寸法と感ガス部の膜厚寸法の相対比率を選定し
て検知対象ガスを設定するので、膜厚や電極間隔を変更
するだけで、検知対象ガスを設定でき、そのため基本的
な構造を変えることなく多種のガスセンサを製造するこ
とができる。Further, according to the invention of claim 4, since the gas to be detected is set by selecting the relative ratio of the interval dimension of the pair of electrodes and the film thickness dimension of the gas sensing portion, the film thickness and the electrode interval are changed. The gas to be detected can be set only by doing so, so that various gas sensors can be manufactured without changing the basic structure.
【００１１】[0011]
【実施例】以下、本発明の実施例を図面を参照して説明
する。図１は本発明のガスセンサのチップの上面構造を
示しており、図示する例では平板状の絶縁基板１にヒー
タ２と、２本で対を為す膜状電極３とを備えるととも
に、膜状電極３の上にＳｎＯ2 、ＺｎＯ、Ｉｎ2 Ｏ3 等
の金属酸化物半導体からなる感ガス部４を形成してセン
サチップ５を構成している。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an upper surface structure of a chip of a gas sensor of the present invention. In the illustrated example, a flat insulating substrate 1 is provided with a heater 2 and a film electrode 3 paired by two, and the film electrode is also provided. A sensor chip 5 is formed by forming a gas sensitive portion 4 made of a metal oxide semiconductor such as SnO 2 , ZnO or In 2 O 3 on the gas sensor 3.
【００１２】ヒータ２は図示例では絶縁基板１の裏面に
設けているが、感ガス部４を設けている絶縁基板１の表
面側に設けてもよく、また絶縁基板１に内蔵して良い。
感ガス部４はスクリーン印刷やスラリーのディスペンサ
による塗布によって形成する。このように形成したセン
サチップ５を図２に示すように基体６に取付け、ケース
７内に収納し、基体６の下面より突出させているピン端
子７に対してワイヤーリード８によりヒータ２及び対の
膜状電極３を電気的に接続し、半導体式ガスセンサを構
成する。尚図２中の９は網体である。Although the heater 2 is provided on the back surface of the insulating substrate 1 in the illustrated example, it may be provided on the front surface side of the insulating substrate 1 on which the gas sensitive portion 4 is provided, or may be built in the insulating substrate 1.
The gas sensitive portion 4 is formed by screen printing or coating with a slurry dispenser. The sensor chip 5 thus formed is attached to the base body 6 as shown in FIG. 2, is housed in the case 7, and the heater 2 and the pair are connected to the pin terminals 7 protruding from the lower surface of the base body 6 by the wire leads 8. The film electrode 3 is electrically connected to form a semiconductor gas sensor. In addition, 9 in FIG. 2 is a net.
【００１３】ところで感ガス部４は膜厚寸法によって何
れのガス中においても抵抗値が変化するが、本発明のガ
スセンサは感ガス部４の膜厚寸法と、対の膜状電極３の
間隔寸法との相対比率により、感ガス部４の抵抗値（ガ
ス感度）が変わることに注目して、この相対比率を設定
することにより検知対象とするガス種を選択するように
したものである。By the way, the resistance value of the gas sensing portion 4 changes in any gas depending on the film thickness dimension. However, in the gas sensor of the present invention, the film thickness dimension of the gas sensing portion 4 and the space dimension of the pair of film electrodes 3 are measured. It should be noted that the resistance value (gas sensitivity) of the gas-sensing section 4 changes depending on the relative ratio with respect to, and the gas type to be detected is selected by setting this relative ratio.
【００１４】つまりｎ型半導体ガスセンサの場合、金属
酸化物半導体からなる感ガス部４に可燃性ガスが吸着す
ると、伝導電子が増加し、センサ抵抗値が小さくなる
（ｐ型半導体ガスセンサの場合にはこの逆となる）。ガ
スセンサの感度を考える上で、ガスの酸化（燃焼）し易
さが、重要な要素の一つであるが、酸化（燃焼）し易さ
はガスの種類によって異なっており、酸化（燃焼）し易
いガス（水素、エタノール等）は感ガス部４の厚みが大
きいと、感ガス部４表面で酸化（燃焼）してしまい、電
気伝導に関与する領域までガスが到達せず、ガス感度が
小さくなる。逆に酸化（燃焼）し難いガス（ＣＨ4 等）
は感ガス部４の厚みの影響が小さい。That is, in the case of the n-type semiconductor gas sensor, when the combustible gas is adsorbed on the gas sensitive portion 4 made of a metal oxide semiconductor, the conduction electrons increase and the sensor resistance value decreases (in the case of the p-type semiconductor gas sensor, The opposite is true). In considering the sensitivity of the gas sensor, the easiness of oxidation (combustion) of the gas is one of the important factors, but the easiness of oxidation (combustion) differs depending on the type of gas, and the oxidation (combustion) If a gas (hydrogen, ethanol, etc.) that is easy to use has a large thickness in the gas sensing portion 4, it will oxidize (burn) on the surface of the gas sensing portion 4, and the gas will not reach the region involved in electrical conduction, and the gas sensitivity will be low. Become. Conversely, a gas that is difficult to oxidize (burn) (CH 4 etc.)
The influence of the thickness of the gas sensitive portion 4 is small.
【００１５】換言すればガス感度は、感ガス部４の電気
伝導にかかわる領域にどれだけのガスが到達するかによ
って決まることになり、この電気伝導にかかわる領域が
膜状電極４の間隔に依存する。一方感ガス部４は連続し
て使用しても経時的な変化が少ないことが望ましく、ま
た耐被毒性の高いものが望まれ、また余り抵抗値の高い
ものでは信号処理回路の特性から見て不適当であり、更
に製造上で抵抗値のばらつきが少ないことが望ましい。In other words, the gas sensitivity is determined by how much gas reaches the region related to electric conduction of the gas sensitive portion 4, and the region related to this electric conduction depends on the distance between the film electrodes 4. To do. On the other hand, it is desirable that the gas sensitive portion 4 be less likely to change with time even if it is continuously used, and that it is highly resistant to poisoning. It is unsuitable, and it is desirable that there is little variation in resistance value in manufacturing.
【００１６】特に膜厚の寸法が小さい場合には抵抗値の
ばらつきが大きく、更に耐被毒性も低い。そこで実験し
てみたところ感ガス部４の膜厚が５０μｍより小さくな
ると顕著になることが分かった。更に経時的変化を測定
してみたところ、感ガス部４の膜厚が５０μｍより小さ
い場合には経時的変化も大きくなるというがことが分か
った。In particular, when the film thickness is small, the resistance value varies widely and the poisoning resistance is low. As a result of an experiment, it was found that when the film thickness of the gas sensitive portion 4 was smaller than 50 μm, it became remarkable. Further, when the change with time was measured, it was found that the change with time was large when the film thickness of the gas sensitive portion 4 was less than 50 μm.
【００１７】図３（ａ）は膜厚の寸法が３０μｍの場合
のガス中の抵抗値の経時変化を示しており、空気
（イ）、メタン（ロ）、エタノール（ハ）の何れに対し
ても経時的変化が大きい。図３（ｂ）は膜厚の寸法が１
８０μｍの場合のガス中の抵抗値の経時変化を示してお
り、空気（イ）、メタン（ロ）、エタノール（ハ）の何
れにおいても一定に安定している。FIG. 3 (a) shows the change over time in the resistance value in the gas when the thickness of the film is 30 μm, and it corresponds to any of air (a), methane (b) and ethanol (c). Also changes significantly over time. In FIG. 3B, the film thickness dimension is 1
It shows the change with time of the resistance value in the gas in the case of 80 μm, and is stable constantly in all of air (a), methane (b) and ethanol (c).
【００１８】他方膜厚の寸法が３００μｍを越えると抵
抗値が高くなって感度が小さくなり、信号処理上に問題
が生じ、更に抵抗値のばらつきも大きいという問題があ
る。而して本発明半導体式センサは感ガス部４の膜厚寸
法の上限を３００μｍとし、下限値を５０μｍとして感
ガス部４の膜厚寸法と、膜状電極４の間隔寸法との相対
比率により、感ガス部４の抵抗値（ガス感度）を調整す
るようにし、所望のガスに対する感度が他のガスに対す
る感度よりも高く弁別性に優れたガスセンサを実現した
ものである。On the other hand, when the thickness of the film exceeds 300 μm, the resistance value becomes high and the sensitivity becomes low, which causes a problem in signal processing and further causes a large variation in the resistance value. Thus, in the semiconductor sensor of the present invention, the upper limit of the film thickness dimension of the gas sensing portion 4 is set to 300 μm, and the lower limit value thereof is set to 50 μm, depending on the relative ratio between the film thickness dimension of the gas sensing portion 4 and the interval dimension of the film electrodes 4. By adjusting the resistance value (gas sensitivity) of the gas sensing portion 4, a gas sensor having higher sensitivity to a desired gas than other gases and excellent in discrimination is realized.
【００１９】図４（ａ）は膜状電極３、３の間隔寸法を
１３０μｍとし、感ガス部４の膜厚寸法を５０μｍ乃至
３００μｍの範囲で変化させた場合の空気（イ）、メタ
ン（ロ）、エタノール（ハ）、イソブタン（ニ）、水素
（ホ）に対する感ガス部４の抵抗値を変化を示してお
り、この図から膜厚寸法により最も小さい抵抗値となる
ガス種が変わっていることが分かる。In FIG. 4A, the distance between the film electrodes 3 and 3 is set to 130 μm, and the film thickness of the gas sensing portion 4 is changed in the range of 50 μm to 300 μm. ), Ethanol (C), isobutane (D), and hydrogen (V), the resistance value of the gas sensitive portion 4 is shown to change. From this figure, the gas type having the smallest resistance value changes depending on the film thickness dimension. I understand.
【００２０】図４（ｂ）は空気（イ）に対する感ガス部
４の抵抗値Ｒ0 と、メタン（ロ）、エタノール（ハ）、
イソブタン（ニ）、水素（ホ）に対する感ガス部４の抵
抗値Ｒの比を膜厚寸法を変えて測定した結果を示してお
り、この図から感ガス部４の膜厚寸法とガス感度の関係
が分かる。尚（イ）は空気を示している。図５（ａ）乃
至（ｃ）は膜状電極３、３の間隔（１３０μｍ）を一定
とし、感ガス部４の膜厚の寸法を５０μｍ、、１８０μ
ｍ、３００μｍとした場合の、各ガス（水素、エタノー
ル、イソブタン、メタン）の濃度とガス感度との関係を
示しており、５０μｍの場合には何れの濃度においても
ガス感度の高い順が水素（ホ）、エタノール（ハ）、イ
ソブタン（ニ）、メタン（ロ）の順となり、この場合水
素、エタノールの検知に適したガスセンサが得られる。FIG. 4B shows the resistance value R 0 of the gas sensing portion 4 to air (a), methane (b), ethanol (c),
The results of measuring the ratio of the resistance value R of the gas sensitive portion 4 to isobutane (d) and hydrogen (e) while changing the film thickness dimension are shown. I understand the relationship. Note that (a) indicates air. 5A to 5C, the distance (130 μm) between the film electrodes 3 and 3 is constant, and the thickness of the gas sensing portion 4 is 50 μm, 180 μm.
m and 300 μm, the relationship between the concentration of each gas (hydrogen, ethanol, isobutane, methane) and the gas sensitivity is shown. In the case of 50 μm, the order of the gas sensitivity is hydrogen ( E), ethanol (c), isobutane (d), methane (b), in that order, and in this case, a gas sensor suitable for detecting hydrogen and ethanol can be obtained.
【００２１】また１８０μｍの場合には、イソブタン
（ニ）、（メタン（ロ）、水素（ホ）、）、エタノール
（ハ）の順となり、イソブタン（ニ）の検知に適したガ
スセンサが得られる。更に３００μｍの場合には、メタ
ン（ロ）、イソブタン（ニ）、（水素（ホ）、エタノー
ル（ハ））の順となり、特にメタン（ロ）の感度が大と
なり、メタン（ロ）に対する弁別性が高いガスセンサが
実現できる。In the case of 180 μm, isobutane (d), (methane (b), hydrogen (e),) and ethanol (c) are in this order, and a gas sensor suitable for detection of isobutane (d) can be obtained. Further, in the case of 300 μm, the order of methane (b), isobutane (d), (hydrogen (e), ethanol (c)) becomes in order, and the sensitivity of methane (b) becomes particularly large, and the discriminability to methane (b) is high. It is possible to realize a high gas sensor.
【００２２】このようにして所望のガスの検知に適した
ガスセンサを、感ガス部４の膜厚寸法と電極間隔の寸法
ととを変えることにより実現することができるのであ
る。尚図５中（イ）は空気を示す。上記の場合膜状電極
３、３の間隔を一定とし、感ガス部４の膜厚の寸法を変
えて所定ガスに対する感度を高くするようにしている
が、図６（ａ）（ｂ）に示すように感ガス部４の膜厚の
寸法Ｘを一定とし、膜状電極３、３の間隔寸法Ｙを変え
ても良い。この場合図６（ａ）は膜状電極３、３の間隔
が図６（ｂ）の場合に比べて大きいため、相対的に感ガ
ス部４の膜厚の寸法が小さなり、膜状電極３、３の間隔
を一定として感ガス部４の膜厚の寸法を小さくした場合
と同様な感度傾向となる。In this way, a gas sensor suitable for detecting a desired gas can be realized by changing the film thickness dimension of the gas sensing portion 4 and the electrode interval dimension. In addition, (a) in FIG. 5 shows air. In the above case, the distance between the film electrodes 3 and 3 is kept constant, and the film thickness of the gas sensitive portion 4 is changed to increase the sensitivity to a predetermined gas. However, as shown in FIGS. As described above, the dimension X of the film thickness of the gas sensing portion 4 may be fixed and the interval dimension Y of the film electrodes 3 may be changed. In this case, in FIG. 6A, the distance between the film electrodes 3 is larger than that in the case of FIG. 6B. The sensitivity tends to be the same as in the case where the film thickness of the gas sensitive portion 4 is reduced by keeping the interval 3 constant.
【００２３】逆に図５（ｂ）の場合には相対的に感ガス
部４の膜厚の寸法が大きくなり、膜状電極３、３の間隔
を一定として感ガス部４の膜厚の寸法を大きくした場合
と同様な感度傾向となる。表１は膜厚を変えた場合と、
電極間隔を変えた場合における比較結果を示しており、
表中（ａ）の半導体センサに対して（ｂ）のように感ガ
ス部４の膜厚の寸法Ｘを変化させた場合と、（ｃ）のよ
うに膜場電極３，３の間隔寸法Ｙを変えて、略その相対
比率Ｘ／Ｙを等しくした場合における空気（イ）、メタ
ン（ロ）、エタノール（ハ）に対する感ガス部４の抵抗
値Ｒ及び空気（イ）の抵抗値をＲ0として夫々の抵抗値
Ｒとの比率をとったガス感度を夫々示しており、各ガス
に対する抵抗値の変化及びガス感度の変化は（ｂ）
（ｃ）とも類似しており、膜厚寸法Ｘを変えても、電極
間隔寸法Ｙを変えても略相対比率が同じであれば同様な
ガス感度が得られることが分かる。On the contrary, in the case of FIG. 5B, the film thickness of the gas sensing portion 4 becomes relatively large, and the film thickness dimension of the gas sensing portion 4 is kept constant with the gap between the film electrodes 3, 3 being constant. The sensitivity tends to be the same as when is increased. Table 1 shows the case where the film thickness is changed,
It shows the comparison results when changing the electrode spacing,
With respect to the semiconductor sensor of (a) in the table, the dimension X of the film thickness of the gas sensing portion 4 is changed as shown in (b), and the spacing dimension Y of the film field electrodes 3, 3 as shown in (c). When the relative ratio X / Y is made substantially equal to each other, the resistance value R of the gas sensing part 4 and the resistance value of the air (a) to air (a), methane (b) and ethanol (c) are set to R 0. And the gas sensitivities obtained by taking the ratios with the respective resistance values R are shown respectively.
It is similar to (c), and it can be seen that even if the film thickness dimension X is changed or the electrode interval dimension Y is changed, similar gas sensitivity can be obtained if the substantially relative ratio is the same.
【００２４】[0024]
【表１】 [Table 1]
【００２５】而して本発明ガスセンサは感ガス部４の膜
厚寸法の下限値を５０μｍ、上限値を３００μｍとして
製造管理を行い、その範囲において膜厚寸法と電極間寸
法を変えることにより、所望のガスに対応するガスセン
サを実現するのである。 つまり感ガス部４の膜厚の上
限値３００μｍと製造限界の最小の電極間隔（例えば２
０μｍ）との組み合わせから、感ガス部４の膜厚の下限
値５０μｍと製造限界の最大の電極間隔（例えば２００
μｍ）の組み合わせまでの範囲において相対比率を変化
させることにより、感度が最大となるガス種を調整する
ことができ、弁別性のよいガスセンサが得られるのであ
る。The gas sensor of the present invention is manufactured by controlling the film thickness of the gas sensing portion 4 with a lower limit of 50 μm and an upper limit of 300 μm, and by changing the film thickness and the inter-electrode dimension within that range, the desired value can be obtained. The gas sensor corresponding to the gas is realized. That is, the upper limit value of the film thickness of the gas sensitive portion 4 is 300 μm and the minimum electrode interval of the manufacturing limit (for example, 2
0 μm), the lower limit value of the film thickness of the gas sensing portion 4 is 50 μm and the maximum electrode interval of the manufacturing limit (for example, 200 μm).
By changing the relative ratio in the range up to the combination of (μm), the gas species having the maximum sensitivity can be adjusted, and a gas sensor with good discriminability can be obtained.
【００２６】ところで感ガス部４は対の膜状電極３、３
が並行している部分全体を感ガス部４で覆うように形成
され、電気伝導に関与する部分に直接ガスが触れないよ
うにするのであるが、並行する部分以外の電極部位も感
ガス部４で覆うようにすればアルコールや水素のように
酸化（燃焼）し易いガスの感度を小さくすることがで
き、望ましくは膜状電極３、３が並行している部分全体
を覆う場合の感ガス部４の各辺の寸法ａ、ｂの略１．２
倍以上（図１においてａ’，ｂ’で示す）となるように
感ガス部４の大きさを設定すれば、アルコールや水素の
ように酸化（燃焼）し易いガスの感度を大幅に小さくす
ることができる。特にアルコールは調理時や、化粧スプ
レー使用時等に発生し、ガスセンサの誤報の原因となる
ので、アルコールの感度を小さくすることが従来より望
まれている。By the way, the gas sensing portion 4 is composed of a pair of film electrodes 3, 3.
Is formed so as to cover the entire parallel portion with the gas sensitive portion 4 so that the gas does not directly touch the portion related to the electric conduction. The sensitivity to a gas that easily oxidizes (combusts) such as alcohol or hydrogen can be reduced by covering it with, and it is desirable that the gas-sensing portion covers the entire portion where the film electrodes 3 and 3 are in parallel. Approximately 1.2 of dimensions a and b on each side of 4
If the size of the gas sensitive portion 4 is set so as to be more than twice (shown by a ′ and b ′ in FIG. 1), the sensitivity of gases such as alcohol and hydrogen that are easily oxidized (burned) is significantly reduced. be able to. In particular, alcohol is generated during cooking, when using a cosmetic spray, etc., and causes a false alarm of the gas sensor. Therefore, it has been conventionally desired to reduce the sensitivity of alcohol.
【００２７】表２は感ガス部４の膜厚寸法が１８０μｍ
で、電極間隔が１３０μｍの場合において、感ガス部４
の各辺ａ’，ｂ’の寸法を変えた場合の空気（イ）、メ
タン（ロ）、エタノール（ハ）に対する感ガス部４の抵
抗値Ｒ及び、空気（イ）の抵抗値をＲ0 として夫々の抵
抗値Ｒとの比率をとったガス感度を測定した結果を示し
ており、この結果から見て（ａ）の場合に比べて（ｂ）
の場合の方がエタノール（ハ）の感度が大ききことが分
かる。In Table 2, the film thickness of the gas sensing portion 4 is 180 μm.
In the case where the electrode interval is 130 μm,
The resistance value R of the gas sensing part 4 to the air (a), methane (b) and ethanol (c) and the resistance value of the air (a) when the dimensions of the respective sides a ′ and b ′ are changed are R 0 As a result, the result of measuring the gas sensitivity by taking the ratio with each resistance value R is shown, and from this result, compared with the case of (a), (b)
It can be seen that in the case of, the sensitivity of ethanol (C) is higher.
【００２８】[0028]
【表２】 [Table 2]
【００２９】尚膜状電極３、３の形状は図１に示す櫛歯
状以外に、図７に示すように直線状の電極であっても良
い。The shape of the film electrodes 3, 3 may be linear electrodes as shown in FIG. 7 other than the comb-teeth shape shown in FIG.
【００３０】[0030]
【発明の効果】請求項１の発明は、対の電極の間隔寸法
と感ガス部の膜厚寸法の相対比率を検知対象ガスに対応
させて設定したものであるから、感ガス部の膜厚寸法や
電極間隔の寸法を変化させたりするだけで、ガス種に対
する感度を変えることができ、そのため検知対象のガス
種が異なるガスセンサを容易に製造することができると
いう効果がある。According to the first aspect of the present invention, the relative ratio of the distance between the pair of electrodes and the film thickness of the gas sensitive portion is set in correspondence with the gas to be detected. The sensitivity to the gas species can be changed only by changing the dimension or the dimension of the electrode interval, and therefore, it is possible to easily manufacture gas sensors having different gas species to be detected.
【００３１】また請求項２の発明は、感ガス部の膜厚寸
法範囲を５０μｍ乃至３００μｍとしたものであるか
ら、感ガス部の抵抗のばらつきが小さく、しかも連続使
用時の感ガス部の経時的な抵抗値の変化（感度変化）が
小さく、更に汚染物質に対する耐被毒性が高いガスセン
サを実現することができるという効果がある。更に請求
項３の発明は、対の電極が並行している部位全体を少な
くとも感ガス部で覆ったものであるから、ノイズガスと
なるアルコール等のような酸化（燃焼）し易いガスの感
度を小さくすることができ、検知対象ガスを確実に検知
できるガスセンサを実現することができるという効果が
ある。According to the second aspect of the present invention, since the film thickness dimension range of the gas sensing portion is 50 μm to 300 μm, the variation in the resistance of the gas sensing portion is small, and the gas sensing portion is aged with continuous use. There is an effect that it is possible to realize a gas sensor that has a small change in resistance value (change in sensitivity) and is highly poisoned to pollutants. Further, according to the invention of claim 3, since at least the entire area where the pair of electrodes are in parallel is covered with the gas sensitive portion, the sensitivity of a gas which easily oxidizes (burns) such as alcohol which becomes noise gas is reduced. Therefore, there is an effect that it is possible to realize a gas sensor that can reliably detect the gas to be detected.
【００３２】更にまた請求項４の発明によれば、対の電
極の間隔寸法と感ガス部の膜厚寸法の相対比率を選定し
て検知対象ガスを設定するので、膜厚や電極間隔を変更
するだけで、検知対象ガスを設定でき、そのため基本的
な構造を変えることなく多種のガスセンサを製造するこ
とができるという効果がある。Further, according to the invention of claim 4, since the gas to be detected is set by selecting the relative ratio of the interval dimension of the pair of electrodes and the film thickness dimension of the gas sensitive portion, the film thickness and the electrode interval are changed. The gas to be detected can be set only by doing so, so that various gas sensors can be manufactured without changing the basic structure.
【図１】本発明の一実施例のセンサチップの拡大上面図
である。FIG. 1 is an enlarged top view of a sensor chip according to an embodiment of the present invention.
【図２】同上の斜視図である。FIG. 2 is a perspective view of the same.
【図３】半導体式ガスセンサの経時安定性の説明用特性
図である。FIG. 3 is a characteristic diagram for explaining temporal stability of the semiconductor gas sensor.
【図４】（ａ）は半導体式ガスセンサの感ガス部の膜厚
寸法とセンサ抵抗値との関係特性図である。（ｂ）は半
導体式ガスセンサの感ガス部の膜厚寸法とガス感度の関
係特性図である。FIG. 4A is a characteristic diagram showing a relationship between a film thickness dimension of a gas sensing portion of a semiconductor gas sensor and a sensor resistance value. FIG. 3B is a characteristic diagram showing the relationship between the film thickness dimension of the gas sensitive portion of the semiconductor gas sensor and the gas sensitivity.
【図５】各膜厚寸法におけるガス濃度とガス感度の関係
特性図である。FIG. 5 is a relationship characteristic diagram of gas concentration and gas sensitivity in each film thickness dimension.
【図６】本発明の別の実施例の説明図である。FIG. 6 is an explanatory diagram of another embodiment of the present invention.
【図７】本発明の他の実施例のセンサチップの拡大上面
図である。FIG. 7 is an enlarged top view of a sensor chip according to another embodiment of the present invention.
１ 絶縁基板 ２ ヒータ ３ 膜状電極 ４ 感ガス部 ５ センサチップ 1 Insulating Substrate 2 Heater 3 Membrane Electrode 4 Gas Sensing Section 5 Sensor Chip
Claims (4)
これらの電極上に形成した金属酸化物半導体からなる感
ガス部とを平板状の絶縁基板に備えた半導体式ガスセン
サにおいて、対の電極の間隔寸法と感ガス部の膜厚寸法
の相対比率を検知対象ガスに対応させて設定して成るこ
とを特徴とする半導体式ガスセンサ。1. A heater and a pair of or a plurality of pairs of electrodes,
In a semiconductor gas sensor equipped with a gas-sensitive part made of a metal oxide semiconductor formed on these electrodes on a flat insulating substrate, the relative ratio between the distance between the pair of electrodes and the film-thickness of the gas-sensitive part is detected. A semiconductor gas sensor characterized by being set according to a target gas.
００μｍとしたことを特徴とする請求項１記載の半導体
式ガスセンサ。2. The film thickness dimension range of the gas sensitive portion is 50 μm to 3
The semiconductor gas sensor according to claim 1, wherein the gas sensor has a diameter of 00 μm.
とも感ガス部で覆ったこと特徴とする請求項１記載の半
導体式ガスセンサ。3. The semiconductor type gas sensor according to claim 1, wherein the entire portion where the pair of electrodes are parallel to each other is covered with at least the gas sensitive portion.
これらの電極上に形成した金属酸化物半導体からなる感
ガス部とを平板状の絶縁基板に備えた半導体式ガスセン
サの対の電極の間隔寸法と感ガス部の膜厚寸法の相対比
率を選定して検知対象ガスを設定することを特徴とする
半導体式ガスセンサの検知対象ガス設定方法。4. A heater and a pair of electrodes or a plurality of pairs of electrodes,
Select the relative ratio between the distance between the pair of electrodes and the film thickness of the gas sensing portion of the semiconductor gas sensor, which has a gas sensing portion made of a metal oxide semiconductor formed on these electrodes on a flat insulating substrate. 2. A method of setting a detection target gas for a semiconductor gas sensor, comprising the step of setting a detection target gas.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28937493A JPH07140102A (en) | 1993-11-18 | 1993-11-18 | Semiconductor gas sensor and method for setting objective gas |
| JP32074898A JPH11218511A (en) | 1993-11-18 | 1998-11-11 | Gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28937493A JPH07140102A (en) | 1993-11-18 | 1993-11-18 | Semiconductor gas sensor and method for setting objective gas |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32074898A Division JPH11218511A (en) | 1993-11-18 | 1998-11-11 | Gas sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07140102A true JPH07140102A (en) | 1995-06-02 |
Family
ID=17742388
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28937493A Pending JPH07140102A (en) | 1993-11-18 | 1993-11-18 | Semiconductor gas sensor and method for setting objective gas |
| JP32074898A Pending JPH11218511A (en) | 1993-11-18 | 1998-11-11 | Gas sensor |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32074898A Pending JPH11218511A (en) | 1993-11-18 | 1998-11-11 | Gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (2) | JPH07140102A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020041833A (en) * | 2018-09-07 | 2020-03-19 | フィガロ技研株式会社 | Gas detection device |
| CN113155905A (en) * | 2021-03-03 | 2021-07-23 | 应急管理部天津消防研究所 | Ag modified ZnO-In2O3Preparation method of gas-sensitive material |
| WO2026032496A1 (en) | 2024-08-06 | 2026-02-12 | Fr-Innovations Gmbh | Attachable camera having a light source, and use of said attachable camera in forestry |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100773025B1 (en) | 2004-02-27 | 2007-11-05 | 이엠씨마이크로시스템 주식회사 | Semiconductor gas sensor, driving method and manufacturing method |
| JP4537830B2 (en) * | 2004-11-09 | 2010-09-08 | エフアイエス株式会社 | Method for manufacturing gas detector and gas detector |
-
1993
- 1993-11-18 JP JP28937493A patent/JPH07140102A/en active Pending
-
1998
- 1998-11-11 JP JP32074898A patent/JPH11218511A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020041833A (en) * | 2018-09-07 | 2020-03-19 | フィガロ技研株式会社 | Gas detection device |
| CN113155905A (en) * | 2021-03-03 | 2021-07-23 | 应急管理部天津消防研究所 | Ag modified ZnO-In2O3Preparation method of gas-sensitive material |
| WO2026032496A1 (en) | 2024-08-06 | 2026-02-12 | Fr-Innovations Gmbh | Attachable camera having a light source, and use of said attachable camera in forestry |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11218511A (en) | 1999-08-10 |
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