JP2003270187A - Semiconductor gas detection element - Google Patents
Semiconductor gas detection elementInfo
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- JP2003270187A JP2003270187A JP2002068384A JP2002068384A JP2003270187A JP 2003270187 A JP2003270187 A JP 2003270187A JP 2002068384 A JP2002068384 A JP 2002068384A JP 2002068384 A JP2002068384 A JP 2002068384A JP 2003270187 A JP2003270187 A JP 2003270187A
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- Prior art keywords
- gas
- zinc oxide
- semiconductor
- gas detection
- detection element
- Prior art date
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- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、酸化亜鉛粒子を主
成分とする金属酸化物半導体ペーストを焼成して作製し
た感応部を有する半導体式ガス検知素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor type gas sensing element having a sensitive portion which is produced by firing a metal oxide semiconductor paste containing zinc oxide particles as a main component.
【０００２】[0002]
【従来の技術】半導体式ガス検知素子は金属酸化物半導
体を主成分とするガス感応部を有し、検知対象ガス（以
下被検知ガスとする）と接触自在に設けられている。被
検知ガスが前記半導体式ガス検知素子に接触して、前記
ガス感応部において前記金属酸化物半導体により酸化さ
れ、その酸化反応に伴う電子の授受に伴い前記半導体式
ガス検知素子の抵抗値が定量的に変化する。そのため、
前記半導体式ガス検知素子を備えたガス検知装置は、前
記抵抗値の変化に基づく出力値から被検知ガスの濃度を
求めることが出来る。2. Description of the Related Art A semiconductor type gas detecting element has a gas sensitive portion containing a metal oxide semiconductor as a main component and is provided so as to be in contact with a gas to be detected (hereinafter referred to as a gas to be detected). The gas to be detected comes into contact with the semiconductor-type gas detection element, is oxidized by the metal oxide semiconductor in the gas-sensing section, and the resistance value of the semiconductor-type gas detection element is quantified with the transfer of electrons accompanying the oxidation reaction. Change. for that reason,
The gas detection device including the semiconductor gas detection element can obtain the concentration of the gas to be detected from the output value based on the change in the resistance value.
【０００３】被検知ガスとしては、メタン（ＣＨ4）や
アルコール等の可燃性ガス、一酸化炭素（ＣＯ）や窒素
酸化物（ＮＯX）ガス等の有毒ガス、硫黄化合物等の悪
臭ガス等があげられ、これらは、金属酸化物を半導体式
ガス検知素子の主成分として利用した前述のガス検知装
置により検知することが出来るため、未然にガス爆発や
ガス中毒等の事故を防ぐことができるのである。The gases to be detected include combustible gases such as methane (CH 4 ) and alcohol, toxic gases such as carbon monoxide (CO) and nitrogen oxides (NO x ), and malodorous gases such as sulfur compounds. These can be detected by the above-described gas detection device that uses a metal oxide as the main component of the semiconductor gas detection element, so that accidents such as gas explosion and gas poisoning can be prevented. is there.
【０００４】前述の悪臭ガスに関して、悪臭の原因とな
る成分として、硫黄化合物、アミン類、カルボン酸類、
ケトン類、アルデヒド類などがあり、これらが大気中に
放出されることによって悪臭ガスとなる。可燃性ガスな
どを検知するには、雰囲気中に検知対象ガス（被検知ガ
ス）が数千ｐｐｍ程度存在するのを検知測定するのに対
して、悪臭ガスを検知測定するためには、例えば１ｐｐ
ｍ以下といった極めて稀薄な悪臭ガスに対して感度を有
することが要求されていた。このような要求を満たすた
めに使用されていた悪臭ガス検知装置として、酸化亜鉛
半導体をガス感応部に有するガス検知装置が使用されて
いた。Regarding the above-mentioned malodorous gas, sulfur compounds, amines, carboxylic acids,
There are ketones, aldehydes, and the like, and when they are released into the atmosphere, they become a foul-smelling gas. In order to detect flammable gas and the like, the detection target gas (gas to be detected) is present in the atmosphere in the order of several thousand ppm, while in order to detect and measure the malodorous gas, for example, 1 pp is used.
It was required to have sensitivity to an extremely rare malodorous gas of m or less. As a malodorous gas detection device used to satisfy such a demand, a gas detection device having a zinc oxide semiconductor in a gas sensitive portion has been used.
【０００５】しかし、このような酸化亜鉛半導体をガス
感応部に有するガス検知装置は、通常の環境レベルに存
在する数十ｐｐｍ程度のアルコール等の検出対象以外の
ガス（妨害ガス）を検知してしまい、本来検知すべき悪
臭ガス（Ｈ2Ｓ等）を検知した場合と区別がつかないと
いう問題点が有った。However, the gas detection device having such a zinc oxide semiconductor in the gas sensitive section detects a gas (interfering gas) other than a detection target such as alcohol of about several tens of ppm existing in a normal environment level. However, there is a problem that it cannot be distinguished from the case where a malodorous gas (H 2 S etc.) which should be detected originally is detected.
【０００６】そのため、酸化亜鉛半導体よりなるガス感
応部の表面に、タングステン、モリブデン、バナジウム
の中から選ばれた少なくとも一種の金属の酸化物を含む
触媒層を具備した半導体式ガス検知素子を設けた悪臭ガ
スセンサが提案された（特開平０４−６６８５７号公
報）。この触媒層は、被検知ガスである悪臭ガスには作
用せず、妨害ガスのみを選択的に分解除去する。そのた
め、前記触媒層を具備した半導体式ガス検知素子は、悪
臭ガスに対して優れた選択性と極めて高いガス感度を有
している。Therefore, a semiconductor gas detecting element having a catalyst layer containing an oxide of at least one metal selected from tungsten, molybdenum and vanadium is provided on the surface of a gas sensitive portion made of a zinc oxide semiconductor. A malodorous gas sensor has been proposed (Japanese Patent Laid-Open No. 04-66857). This catalyst layer does not act on the malodorous gas which is the gas to be detected, and selectively decomposes and removes only the interfering gas. Therefore, the semiconductor-type gas detection element equipped with the catalyst layer has excellent selectivity for malodorous gas and extremely high gas sensitivity.
【０００７】[0007]
【発明が解決しようとする課題】上述した酸化亜鉛を感
応部として有する半導体式ガス検知素子は、硫黄化合物
を含む悪臭を高感度に検出することが可能であるが、以
下の問題点を有していた。
（１）ガス検知時の応答が遅い。９０％応答時間（メー
ターの指示値の変化が始まってから、飽和出力の９０％
に達するまでに要した時間）に２１０秒以上要する。
（２）被検知ガス中から清浄空気に戻した時のセンサ出
力の復帰が遅い。例えば、１ｐｐｍＨ2Ｓ検知後、清浄
空気中に戻した時に、センサ出力が０．０１ｐｐｍＨ2
Ｓ相当出力のレベルまで復帰するのに５６０秒以上要す
るため、１点の測定に多大な時間を要し非効率的であっ
た。
（３）ウォーミングアップ時間（電源を印加してからガ
ス検知可能な状態になるまでの時間）が長い。例えば、
１週間無通電で放置した状態から電源印加後、センサ出
力が０．０１ｐｐｍＨ2Ｓ相当出力の１／２レベルまで
復帰するのに３０分以上要するため、実使用上、非常に
不便であった。
（４）低湿度領域における湿度依存性が大きく、測定値
が大きく影響を受けるため、信頼性のある測定が困難で
あった。The semiconductor type gas detection element having the above-mentioned zinc oxide as a sensitive portion can detect a malodor containing a sulfur compound with high sensitivity, but has the following problems. Was there. (1) The response at the time of gas detection is slow. 90% response time (90% of saturated output since the change of the indicated value of the meter started
It takes 210 seconds or more to reach (). (2) The recovery of the sensor output is slow when the detected gas is returned to clean air. For example, after returning to the clean air after detecting 1ppmH 2 S, the sensor output is 0.01ppmH 2
Since it takes 560 seconds or more to return to the level of S-equivalent output, it takes a lot of time to measure one point, which is inefficient. (3) The warming-up time (the time from the application of power to the state in which gas detection is possible) is long. For example,
It took 30 minutes or more for the sensor output to return to 1/2 level of the output equivalent to 0.01 ppm H 2 S after power was applied from a state where it was left unpowered for 1 week, which was very inconvenient in actual use. (4) Since the humidity dependency in the low humidity region is large and the measured value is greatly affected, reliable measurement is difficult.
【０００８】このような問題点が有るため、限られた条
件、限られた用途でしか使用できなかった。Due to such problems, it can only be used under limited conditions and limited applications.
【０００９】従って、本発明の目的は、実使用に際して
効率よく検知作業が行え、かつ、信頼性の高い半導体式
ガス検知素子を提供することにある。Therefore, an object of the present invention is to provide a highly reliable semiconductor type gas detection element which can perform detection work efficiently in actual use.
【００１０】[0010]
【課題を解決するための手段】本発明者らは、上記目的
を達成すべく、前記ガス感応部材料を改質することに着
目して鋭意研究したところ、酸化亜鉛に酸化亜鉛より活
性の高い所定量の酸化スズを添加することにより、酸化
亜鉛の持っていた硫黄化合物を含む被検知ガスに高感度
である特性を維持しつつ、硫黄化合物を含む被検知ガス
に対する酸化活性が高まり、かつ、ガス感応部における
吸脱着を含む反応速度が速まることを見出し、本発明を
完成するに至った。さらに、酸化亜鉛の所定量を超微粒
子酸化亜鉛とすることによりウォーミングアップに要す
る時間の短縮が認められ、さらに、前記ガス感応部にＰ
ｂ，Ｃｕ，Ｆｅ，Ｎｉ，Ｃｏの金属酸化物の少なくとも
一種を担持させることにより、硫黄化合物を含む被検知
ガスに対して、ガス検知時の応答時間、清浄空気に戻し
た時の復帰時間の短縮が認められるといった優れた特性
を付与することができることも新たに見出した。ここ
で、超微粒子酸化亜鉛とは、酸化亜鉛の平均粒子径が５
０ｎｍ以下の酸化亜鉛を指すものとする。[Means for Solving the Problems] The inventors of the present invention have made earnest researches in order to achieve the above object by focusing on modifying the gas sensitive part material. As a result, zinc oxide has a higher activity than zinc oxide. By adding a predetermined amount of tin oxide, while maintaining the characteristics of zinc oxide having a high sensitivity to the detection gas containing a sulfur compound, the oxidation activity for the detection gas containing a sulfur compound is increased, and The inventors have found that the reaction rate including adsorption / desorption in the gas sensitive part is accelerated, and have completed the present invention. Furthermore, by using a predetermined amount of zinc oxide as ultrafine zinc oxide, it was confirmed that the time required for warming up was shortened.
By supporting at least one of the metal oxides of b, Cu, Fe, Ni, and Co, the response time at the time of gas detection and the recovery time at the time of returning to clean air for the detected gas containing a sulfur compound It was newly found that excellent characteristics such as shortening can be imparted. Here, the ultrafine zinc oxide has an average particle diameter of zinc oxide of 5
It refers to zinc oxide of 0 nm or less.
【００１１】〔構成１〕この目的を達成するための本発
明の特徴構成は、請求項１に記載のように、酸化亜鉛粒
子を主成分とする金属酸化物半導体ペーストを焼成して
作製した感応部を有する半導体式ガス検知素子であっ
て、前記金属酸化物半導体ペーストが、前記酸化亜鉛粒
子に対して酸化スズ粒子を２〜１０重量％含むことを特
徴とすることにある。[Structure 1] A characteristic structure of the present invention for attaining this object is, as described in claim 1, a reaction prepared by firing a metal oxide semiconductor paste containing zinc oxide particles as a main component. The metal oxide semiconductor paste is characterized by containing 2 to 10% by weight of tin oxide particles with respect to the zinc oxide particles.
【００１２】〔作用効果１〕つまり、前記金属酸化物半
導体ペーストが、前記酸化亜鉛粒子に対して酸化スズ粒
子を２〜１０重量％含むことにより、後述の実施例１
（ａ）〜（ｆ）に示したように、酸化亜鉛に対する酸化
スズの重量％が２重量％以上である場合には、（ａ）ガ
ス検知時の応答時間が１／５〜１／１０に短縮し、
（ｂ）被検知ガス中から清浄空気に戻した時のセンサ出
力の復帰時間が１／３〜１／６に短縮し、かつ（ｃ）ウ
ォーミングアップ時間が１／３〜１／５に短縮する。ま
た、酸化亜鉛に対する酸化スズの重量％が２〜１０重量
％である場合には、（ｄ）低湿度領域における湿度依存
性が小さくなり（湿度変動によるメータの指示値の変動
が１／２．５〜１／５になる）、（ｅ）被検知ガスに対
する感度が約２〜４倍高くなる。さらに、酸化亜鉛に対
する酸化スズの重量％を１０重量％以下とすることによ
り、（ｆ）ガス選択性が優れたものとなる。[Operation and Effect 1] That is, since the metal oxide semiconductor paste contains 2 to 10% by weight of tin oxide particles with respect to the zinc oxide particles, the following Example 1 will be described.
As shown in (a) to (f), when the weight percentage of tin oxide to zinc oxide is 2 wt% or more, (a) the response time at the time of gas detection becomes 1/5 to 1/10. Shorten,
(B) The recovery time of the sensor output when returning from the detected gas to clean air is shortened to 1/3 to 1/6, and (c) the warming-up time is shortened to 1/3 to 1/5. Further, when the weight% of tin oxide to zinc oxide is 2 to 10% by weight, (d) the humidity dependency in the low humidity region becomes small (the fluctuation of the indicated value of the meter due to the humidity fluctuation is 1/2. 5 to 1/5), and (e) the sensitivity to the gas to be detected becomes about 2 to 4 times higher. Further, by setting the weight percentage of tin oxide to zinc oxide to be 10 wt% or less, (f) gas selectivity becomes excellent.
【００１３】これらより、酸化亜鉛に対する酸化スズ添
加量を２〜１０重量％とすることにより、ガス検知時の
応答時間や被検知ガス中から清浄空気に戻した時のセン
サ出力の復帰が速くなるため、１サンプル当たりの測定
時間が大幅に短縮されるため測定の効率化が実現すると
共に測定精度が増し、高性能化が実現する。また、ウォ
ーミングアップ時間が短縮することにより、電源印加
後、被検知ガスの測定が効率的に行えるようになり、低
湿度領域における湿度依存性が改善されたため、測定可
能な条件、用途が広がり、高精度な測定が可能となっ
た。さらに、このような半導体式ガス検知素子は、硫化
水素等の被検知ガス感度や被検知ガスと妨害ガスとの選
択性に優れた特性を有するものであるため、被検知ガス
を精度良く検知できる信頼性の高い半導体式ガス検知素
子を提供することが可能となるのである。From the above, by setting the amount of tin oxide added to zinc oxide to be 2 to 10% by weight, the response time at the time of gas detection and the restoration of the sensor output when returning from the gas to be detected to clean air become faster. Therefore, the measurement time per sample is significantly shortened, so that the efficiency of the measurement is improved, the measurement accuracy is increased, and the performance is improved. Also, by shortening the warm-up time, it becomes possible to efficiently measure the gas to be detected after power is applied, and the humidity dependency in the low humidity region has been improved. Accurate measurement is now possible. Further, since such a semiconductor type gas detection element has characteristics such that the sensitivity of the gas to be detected such as hydrogen sulfide and the selectivity between the gas to be detected and the interfering gas are excellent, the gas to be detected can be accurately detected. It is possible to provide a highly reliable semiconductor gas detection element.
【００１４】〔構成２〕この目的を達成するための本発
明の特徴構成は、請求項２に記載のように、上記構成１
において、前記酸化亜鉛粒子の少なくとも１０重量％が
超微粒子酸化亜鉛であれば好ましく、請求項３に記載の
ように、前記超微粒子酸化亜鉛は、ガス化した金属亜鉛
に酸素を供給して製造されたものであれば好ましい。[Structure 2] The characteristic structure of the present invention for attaining this object is, as described in claim 2, the structure 1 described above.
In the above, it is preferable that at least 10% by weight of the zinc oxide particles is ultrafine zinc oxide, and the ultrafine zinc oxide is produced by supplying oxygen to gasified metal zinc as described in claim 3. It is preferable if it is
【００１５】〔作用効果２〕つまり、前記酸化亜鉛粒子
の少なくとも１０重量％が超微粒子酸化亜鉛とすること
により、後述の実施例２に示したように、ウォーミング
アップに要する時間が、構成１の半導体式ガス検知素子
と比べて半分に短縮される。これにより、構成１の半導
体式ガス検知素子と比べてさらに測定の効率化が実現可
能な半導体式ガス検知素子を提供できる。[Advantageous Effect 2] That is, by using at least 10% by weight of the zinc oxide particles as ultrafine zinc oxide, the time required for warming up can be increased as shown in Example 2 to be described later. It is shortened to half compared with the conventional gas sensing element. As a result, it is possible to provide a semiconductor-type gas detection element that can realize more efficient measurement as compared with the semiconductor-type gas detection element of configuration 1.
【００１６】さらに、前記超微粒子酸化亜鉛は、ガス化
した金属亜鉛に酸素を供給して製造されたものであれ
ば、平均粒子径が５０ｎｍ以下の超微粒子酸化亜鉛を製
造することができる。そして、このような粒子径を有す
る前記超微粒子酸化亜鉛を使用することにより、酸化亜
鉛全体の比表面積が大きくなり、その結果酸化亜鉛と酸
化スズとの接触面積が増し、酸化亜鉛より活性の高い酸
化スズを添加する効果をより顕著なものにすることがで
きる。Further, if the ultrafine zinc oxide is produced by supplying oxygen to gasified metal zinc, ultrafine zinc oxide having an average particle diameter of 50 nm or less can be produced. By using the ultrafine zinc oxide having such a particle diameter, the specific surface area of the entire zinc oxide is increased, and as a result, the contact area between zinc oxide and tin oxide is increased, and the activity is higher than that of zinc oxide. The effect of adding tin oxide can be made more remarkable.
【００１７】〔構成３〕この目的を達成するための本発
明の特徴構成は、請求項４に記載のように、上記構成１
〜２において、前記感応部に、Ｐｂ，Ｃｕ，Ｆｅ，Ｎ
ｉ，Ｃｏの金属酸化物のうち少なくとも一種を担持させ
てあれば好ましい。[Structure 3] The characteristic structure of the present invention for achieving this object is, as described in claim 4, the structure 1 described above.
2 to Pb, Cu, Fe, N in the sensitive portion.
It is preferable that at least one of the metal oxides of i and Co is supported.
【００１８】〔作用効果３〕つまり、前記感応部に、Ｐ
ｂ，Ｃｕ，Ｆｅ，Ｎｉ，Ｃｏの金属酸化物のうち少なく
とも一種を担持させてあれば、前記感応部に金属酸化物
を担持させない場合と比較すると、後述の実施例３
（ａ）〜（ｃ）に示したように、９０％応答時間は２／
５〜４／５に短縮し、復帰時間は１／２〜４／５に短縮
し、ウォーミングアップ時間は１／２〜５／６に短縮す
る。[Effect 3] In other words, P is added to the sensitive section.
When at least one of the metal oxides of b, Cu, Fe, Ni, and Co is supported, as compared with the case where no metal oxide is supported on the sensitive part, the third embodiment described later is performed.
As shown in (a) to (c), 90% response time is 2 /
It is shortened to 5 to 4/5, the recovery time is shortened to 1/2 to 4/5, and the warm-up time is shortened to 1/2 to 5/6.
【００１９】これにより、構成１〜２の半導体式ガス検
知素子と比べてさらに測定の効率化が実現可能な半導体
式ガス検知素子を提供できる。As a result, it is possible to provide a semiconductor-type gas detection element capable of further improving the efficiency of measurement as compared with the semiconductor-type gas detection elements having the configurations 1 and 2.
【００２０】[0020]
【発明の実施の形態】以下に本発明の実施の形態を図面
に基づいて説明するが、本発明は、これらによって限定
されるものではない。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.
【００２１】本発明の半導体式ガス検知素子は、図１に
示したように、アルミナ基板３の上面に酸化亜鉛と酸化
スズの混合物よりなるガス感応部２と、前記ガス感応部
２の電気抵抗を検知する白金電極４ａ〜４ｂと、前記ア
ルミナ基板３の下面にヒータ５とを有する基板型半導体
式ガス検知素子１とすることができる。As shown in FIG. 1, the semiconductor gas detecting element of the present invention has a gas sensitive portion 2 made of a mixture of zinc oxide and tin oxide on the upper surface of an alumina substrate 3, and an electric resistance of the gas sensitive portion 2. The substrate type semiconductor gas detecting element 1 having the platinum electrodes 4a to 4b for detecting the temperature and the heater 5 on the lower surface of the alumina substrate 3 can be used.
【００２２】前記酸化亜鉛は、所定濃度の塩化亜鉛水溶
液に、所定濃度のアンモニア水を滴下して水酸化亜鉛の
沈殿物を得た後、前記沈殿物を水洗、乾燥後、電気炉で
６００℃、２時間焼成することにより得ることができ
る。The zinc oxide is prepared by dropping ammonia water having a predetermined concentration into an aqueous solution of zinc chloride having a predetermined concentration to obtain a precipitate of zinc hydroxide, washing the precipitate with water and drying it, and then heating it at 600 ° C. in an electric furnace. It can be obtained by firing for 2 hours.
【００２３】前記酸化スズは、所定濃度の四塩化スズ水
溶液に、所定濃度のアンモニア水を滴下して水酸化スズ
の沈殿物を得た後、前記沈殿物を水洗、乾燥後、電気炉
で６００℃、２時間焼成することにより得ることができ
る。The tin oxide is prepared by dropping ammonia water having a predetermined concentration into an aqueous solution of tin tetrachloride having a predetermined concentration to obtain a tin hydroxide precipitate, washing the precipitate with water, and drying it. It can be obtained by baking at 2 ° C. for 2 hours.
【００２４】このようにして得られた前記酸化亜鉛およ
び前記酸化スズを所定の割合に混合し、水で練って、前
記酸化亜鉛と前記酸化スズの混合物ペースト（金属酸化
物半導体ペースト）を作製する。また、ガス感応部２の
電気抵抗を検知する白金電極４ａ〜４ｂ及びアルミナ基
板３の他面にヒータ５を形成して素子基体を作製してお
く。前記金属酸化物半導体ペーストを前記素子基体の白
金電極４ａ〜４ｂを覆うように塗布し、乾燥後、９００
℃で２時間焼成することにより、酸化亜鉛および酸化ス
ズからなる金属酸化物半導体をガス感応部２とする基板
型半導体式ガス検知素子１を得ることができる。The zinc oxide and the tin oxide thus obtained are mixed in a predetermined ratio and kneaded with water to prepare a mixture paste (metal oxide semiconductor paste) of the zinc oxide and the tin oxide. . Further, a heater 5 is formed on the platinum electrodes 4a and 4b for detecting the electric resistance of the gas sensitive portion 2 and the other surface of the alumina substrate 3 to prepare an element substrate. The metal oxide semiconductor paste is applied so as to cover the platinum electrodes 4a-4b of the element substrate, dried, and then 900
By firing at a temperature of 2 ° C. for 2 hours, it is possible to obtain the substrate-type semiconductor gas detection element 1 having the metal oxide semiconductor composed of zinc oxide and tin oxide as the gas sensitive portion 2.
【００２５】[実施例１]以下に、酸化亜鉛に対して酸化
スズを、それぞれ、１、２、３、５、１０、１５、２
０、２５重量％添加して上記の方法により基板型半導体
式ガス検知素子１を作製し、各基板型半導体式ガス検知
素子１の諸特性（ガス検知時の応答時間、被検知ガス中
から清浄空気に戻した時のセンサ出力の復帰時間、ウォ
ーミングアップ時間、湿度依存性、被検知ガスに対する
感度、ガス選択性）を調べた。尚、下記に示すデータ
は、上記各重量％の酸化スズを含有する基板型半導体式
ガス検知素子１を各１０個づつ作製してその平均値を求
めたものであり、表中の「酸化スズ／酸化亜鉛（％）」
は、酸化亜鉛に対する酸化スズの重量％を示したもので
あり、「０」は、酸化スズを添加しない従来の酸化亜鉛
よりなるガス感応部２を有する基板型半導体式ガス検知
素子１のことを示したものである。[Example 1] Below, tin oxide was added to zinc oxide to give 1, 2, 3, 5, 10, 15, 2 respectively.
The substrate type semiconductor gas detecting element 1 was manufactured by the above method by adding 0, 25% by weight, and various characteristics of each substrate type semiconductor gas detecting element 1 (response time at gas detection, cleaning from detected gas) The recovery time of the sensor output when returning to air, warming-up time, humidity dependency, sensitivity to the detected gas, gas selectivity) were investigated. The data shown below are obtained by preparing ten substrate-type semiconductor gas detection elements 1 each containing tin oxide by the above-mentioned weight% and determining the average value thereof. / Zinc oxide (%) "
Represents the weight% of tin oxide with respect to zinc oxide, and “0” represents the substrate type semiconductor gas detection element 1 having the gas sensitive part 2 made of conventional zinc oxide to which tin oxide is not added. It is shown.
【００２６】（ａ）ガス検知時の応答時間
表１に、酸化亜鉛に対する酸化スズの重量％を種々変更
して作製したガス感応部２を有する基板型半導体式ガス
検知素子１を用いて、１ｐｐｍの硫化水素に対する９０
％応答時間を調べた結果を示した。(A) Response time at the time of gas detection In Table 1, a substrate type semiconductor gas detection element 1 having a gas sensitive portion 2 prepared by changing the weight% of tin oxide with respect to zinc oxide was used. 90 to hydrogen sulfide
The results of examining the% response time are shown.
【００２７】[0027]
【表１】 [Table 1]
【００２８】この結果より、酸化スズの重量％が上昇す
るに従い、９０％応答時間が短縮されることが判明し
た。また、酸化スズを１重量％添加した場合でも応答時
間を短縮する効果はあるが、酸化スズを２重量％以上添
加した場合で９０％応答時間が従来の１／５〜１／１０
に短縮するという顕著な効果を示した。From these results, it was found that the response time was shortened by 90% as the weight percentage of tin oxide increased. Moreover, although the addition of 1% by weight of tin oxide has the effect of shortening the response time, the addition of 2% by weight or more of tin oxide results in 90% response time being 1/5 to 1/10 that of the conventional one.
The remarkable effect of shortening to.
【００２９】（ｂ）被検知ガス中から清浄空気に戻した
時のセンサ出力の復帰時間
表２に、酸化亜鉛に対する酸化スズの重量％を種々変更
して作製したガス感応部２を有する基板型半導体式ガス
検知素子１を用いて、１ｐｐｍ硫化水素曝露後、０．０
１ｐｐｍ硫化水素に相当する出力レベルまで復帰する時
間（復帰時間）を調べた結果を示した。(B) Recovery time of sensor output when returning to clean air from the gas to be detected Table 2 is a substrate type having a gas sensitive portion 2 produced by changing various weight% of tin oxide to zinc oxide. Using the semiconductor gas detection element 1, after exposure to 1 ppm hydrogen sulfide, 0.0
The results of examining the time (recovery time) for returning to the output level corresponding to 1 ppm hydrogen sulfide are shown.
【００３０】[0030]
【表２】 [Table 2]
【００３１】この結果より、酸化スズの重量％が上昇す
るに従い、０．０１ｐｐｍ硫化水素に相当する出力レベ
ルへの復帰時間が短縮されることが判明した。また、酸
化スズを１重量％添加した場合でも復帰時間を短縮する
効果はあるが、酸化スズを２重量％以上添加した場合で
復帰時間が従来の１／３〜１／６に短縮するという顕著
な効果を示した。From these results, it was found that the recovery time to the output level corresponding to 0.01 ppm hydrogen sulfide was shortened as the weight percentage of tin oxide increased. Further, although adding 1% by weight of tin oxide has the effect of shortening the recovery time, adding 2% by weight or more of tin oxide shortens the recovery time to 1/3 to 1/6 of the conventional one. Showed a significant effect.
【００３２】（ｃ）ウォーミングアップ時間
表３に、酸化亜鉛に対する酸化スズの重量％を種々変更
して作製したガス感応部２を有する基板型半導体式ガス
検知素子１を用いて、ウォーミングアップに要する時間
を調べた結果を示した。ここで、ウォーミングアップに
要する時間として、１週間無通電放置（電源を切った状
態）の後、電源を印加してからセンサ出力が０．０１ｐ
ｐｍ硫化水素に対する出力の１／２以下に戻るまでに要
した時間を測定基準とした。(C) Warming-up time Table 3 shows the time required for warming-up using the substrate type semiconductor gas detecting element 1 having the gas sensitive section 2 prepared by changing the weight% of tin oxide to zinc oxide variously. The results of the examination are shown. Here, as the time required for warming up, the sensor output is 0.01 p after the power is applied after leaving it unpowered for one week (the power is turned off).
The time required for the output to return to ½ or less of the output for pm hydrogen sulfide was used as the measurement standard.
【００３３】[0033]
【表３】 [Table 3]
【００３４】この結果より、酸化スズの重量％が上昇す
るに従い、ウォーミングアップ時間は短縮することが判
明した。また、酸化スズを１重量％添加した場合でもウ
ォーミングアップ時間を短縮する効果はあるが、酸化ス
ズを２重量％以上添加した場合でウォーミングアップ時
間が従来の１／３〜１／５に短縮するという顕著な効果
を示した。ウォーミングアップ時間が短縮されたメカニ
ズムとして、酸化亜鉛より活性の高い酸化スズを加える
ことによりガス感応部２の活性が高まるため、吸脱着を
含む反応速度が速まり、これにより、無通電放置中に吸
着した各種物質の脱着が速まることにより短時間に前記
ガス感応部２をリフレッシュできたため、ウォーミング
アップ時間が短縮したものと考えられる。From these results, it was found that the warm-up time was shortened as the weight percentage of tin oxide increased. Moreover, although adding 1% by weight of tin oxide has the effect of shortening the warming-up time, adding 2% by weight or more of tin oxide shortens the warming-up time to 1/3 to 1/5 of the conventional one. Showed a significant effect. As a mechanism for shortening the warming-up time, the activity of the gas sensitive part 2 is increased by adding tin oxide, which is more active than zinc oxide, so that the reaction rate including adsorption / desorption is accelerated, which results in adsorption during de-energization. It is considered that the warming-up time was shortened because the gas sensitive part 2 could be refreshed in a short time due to the quick desorption of the various substances.
【００３５】（ｄ）湿度依存性
表４に、酸化亜鉛に対する酸化スズの重量％を種々変更
して作製したガス感応部２を有する基板型半導体式ガス
検知素子１を用いて４ｇ／ｍ3の湿度において０．１ｐ
ｐｍであったメータの指示値が、湿度を４→２０ｇ／ｍ
3に変化させた場合にどのように変化したかを調べた結
果を示した。(D) Humidity Dependency In Table 4, the substrate type semiconductor gas detection element 1 having the gas sensitive portion 2 prepared by changing the weight% of tin oxide to zinc oxide was changed to 4 g / m 3 . 0.1p in humidity
The indicated value of the meter, which was pm, changes the humidity from 4 to 20 g / m.
The results of investigating how it changed when it was changed to 3 are shown.
【００３６】[0036]
【表４】 [Table 4]
【００３７】この結果より、酸化スズを添加することに
より、メータの指示値の変動幅が小さくなることが判明
した。さらに、酸化スズを２〜１０重量％添加した場合
で変動幅が従来の１／２．５〜１／５になるという顕著
な効果を示した。従来の酸化亜鉛よりなるガス感応部を
有する半導体式ガス検知素子では、その清浄空気中での
抵抗値が湿度変動により影響を受けることは殆どない
が、硫化水素に対する感度が、低湿度領域の湿度変動に
より大きく影響を受ける。これに対して、従来の酸化ス
ズよりなるガス感応部を有する半導体式ガス検知素子で
は、清浄空気中での抵抗値が湿度変動により大きく影響
を受けるが、硫化水素に対する感度は湿度変動により影
響を受けることが少ない。このため、本発明のように、
酸化亜鉛に酸化スズを２〜１０重量％添加することによ
り、酸化亜鉛と酸化スズの良い特性が現れ、清浄空気中
抵抗値や硫化水素に対する感度共に湿度変動により影響
を受け難くなると考えられる。From this result, it was found that the fluctuation range of the indicated value of the meter was reduced by adding tin oxide. Further, when tin oxide was added in an amount of 2 to 10% by weight, the fluctuation range was 1 / 2.5 to 1/5 of the conventional value, which was a remarkable effect. In a conventional semiconductor gas detection element having a gas sensitive part made of zinc oxide, its resistance value in clean air is hardly affected by humidity fluctuation, but its sensitivity to hydrogen sulfide is low in the low humidity range. Greatly affected by fluctuations. On the other hand, in the conventional semiconductor gas detection element having a gas sensitive section made of tin oxide, the resistance value in clean air is greatly affected by humidity fluctuations, but the sensitivity to hydrogen sulfide is affected by humidity fluctuations. Less likely to receive. Therefore, as in the present invention,
It is considered that by adding 2 to 10% by weight of tin oxide to zinc oxide, good characteristics of zinc oxide and tin oxide appear, and both resistance value in clean air and sensitivity to hydrogen sulfide are less affected by humidity fluctuation.
【００３８】（ｅ）被検知ガスに対する感度
表５に、酸化亜鉛に対する酸化スズの重量％を種々変更
して作製したガス感応部２を有する基板型半導体式ガス
検知素子１を用いて、０．０１ｐｐｍ硫化水素に対する
出力を調べた結果を示した。(E) Sensitivity to gas to be detected In Table 5, the substrate type semiconductor gas detecting element 1 having the gas sensitive portion 2 prepared by changing the weight% of tin oxide to zinc oxide was used. The results of examining the output for 01 ppm hydrogen sulfide are shown.
【００３９】[0039]
【表５】 [Table 5]
【００４０】この結果より、酸化スズの添加量が増加す
るに従い、硫化水素に対する感度は高感度化して５重量
％で最大となり、５重量％以上では感度が低下すること
が判った。特に、酸化スズの添加量が２〜１０重量％に
おいて、従来の酸化亜鉛よりなる半導体式ガス検知素子
より約２〜４倍感度が高くなっている。これは、酸化亜
鉛より活性の高い酸化スズを加えることにより、硫黄化
合物を含む被検知ガスに対する酸化活性が高まるため高
感度化するが、酸化スズの添加量が１０重量％以上で
は、酸化スズの特性が優勢となり、硫黄化合物を含む被
検知ガスに対する感度が低感度化したものと考えられ
る。From these results, it was found that as the amount of tin oxide added was increased, the sensitivity to hydrogen sulfide was increased to the maximum at 5% by weight and decreased at 5% by weight or more. In particular, when the amount of tin oxide added is 2 to 10% by weight, the sensitivity is about 2 to 4 times higher than that of the conventional semiconductor gas detection element made of zinc oxide. This is because the addition of tin oxide, which is more active than zinc oxide, increases the oxidative activity for the gas to be detected containing the sulfur compound, resulting in higher sensitivity, but when the amount of tin oxide added is 10% by weight or more, tin oxide It is considered that the characteristics became dominant and the sensitivity to the detected gas containing a sulfur compound was lowered.
【００４１】（ｆ）ガス選択性
表６に、酸化亜鉛に対する酸化スズの重量％を種々変更
して作製したガス感応部２を有する基板型半導体式ガス
検知素子１を用いて、０．１ ｐｐｍ硫化水素に対する
出力と同一出力を与えるエタノール濃度を調べた結果を
示した。(F) Gas Selectivity In Table 6, 0.1 ppm was obtained by using the substrate type semiconductor gas detecting element 1 having the gas sensitive portion 2 prepared by changing the weight% of tin oxide to zinc oxide variously. The results of examining the concentration of ethanol giving the same output as that for hydrogen sulfide are shown.
【００４２】[0042]
【表６】 [Table 6]
【００４３】この結果より、酸化スズの重量％が上昇す
るに従い、０．１ ｐｐｍ硫化水素に対する出力と同一
出力を与えるエタノール濃度が減少していることから、
エタノールに対する感度は増大することが判った。その
ため、酸化スズの添加量の多いガス検知素子では、硫黄
化合物を含む被検知ガスを選択的に検知することが困難
となる。これは、酸化スズのエタノールに対する感度は
大きいため、添加量の上昇と共に、ガス検知素子は酸化
スズ特性が優勢となり、エタノールに対する感度が増加
すると考えられる。特に、酸化スズ添加量が１０重量％
以上で、ガス選択性の喪失が顕著となるため、酸化スズ
添加量を１０重量％以下とすることにより、ガス選択性
の優れた半導体式ガス検知素子とすることができる。From this result, as the weight% of tin oxide increases, the concentration of ethanol giving the same output as that for 0.1 ppm hydrogen sulfide decreases,
It was found that the sensitivity to ethanol was increased. Therefore, it becomes difficult for the gas detection element containing a large amount of tin oxide to selectively detect the detection target gas containing the sulfur compound. It is considered that since tin oxide has a high sensitivity to ethanol, the tin oxide property becomes dominant in the gas detection element as the amount of addition increases, and the sensitivity to ethanol increases. In particular, the amount of tin oxide added is 10% by weight
As described above, the loss of gas selectivity becomes remarkable. Therefore, by setting the amount of tin oxide added to 10% by weight or less, it is possible to obtain a semiconductor gas detection element having excellent gas selectivity.
【００４４】つまり、（ａ）〜（ｆ）より、酸化亜鉛に
対する酸化スズ添加量を２〜１０重量％としたガス感応
部を有する半導体式ガス検知素子とすることにより、ガ
ス検知時の応答時間や被検知ガス中から清浄空気に戻し
た時のセンサ出力の復帰が速くなるため、１サンプル当
たりの測定時間が大幅に短縮されるため測定の効率化が
実現すると共に測定精度が増し、高性能化が実現する。
また、ウォーミングアップ時間が短縮することにより、
電源印加後、被検知ガスの測定が効率的に行えるように
なり、低湿度領域における湿度依存性が改善されたた
め、測定可能な条件、用途が広がり、高精度な測定が可
能となった。さらに、このような半導体式ガス検知素子
は、硫化水素等の被検知ガス感度や被検知ガスと妨害ガ
スとの選択性に優れた特性を有するものであるため、被
検知ガスを精度良く検知できる信頼性の高い半導体式ガ
ス検知素子を提供することが可能となる。That is, from (a) to (f), by using a semiconductor type gas detection element having a gas sensitive portion in which the amount of tin oxide added to zinc oxide is 2 to 10% by weight, the response time during gas detection is improved. Since the sensor output returns faster when the temperature of the detected gas is changed to clean air, the measurement time per sample is greatly shortened, and the measurement efficiency is improved and the measurement accuracy is increased, resulting in high performance. Is realized.
Also, by shortening the warm-up time,
After applying the power supply, the gas to be detected can be measured efficiently, and the humidity dependence in the low humidity region has been improved, so the measurable conditions and applications have expanded, and high-precision measurement has become possible. Further, since such a semiconductor type gas detection element has characteristics such that the sensitivity of the gas to be detected such as hydrogen sulfide and the selectivity between the gas to be detected and the interfering gas are excellent, the gas to be detected can be accurately detected. It is possible to provide a highly reliable semiconductor gas detection element.
【００４５】尚、（ａ）〜（ｆ）より、酸化亜鉛に対す
る酸化スズ添加量を２重量％以下、あるいは１０重量％
以上としたガス感応部２を有する基板型半導体式ガス検
知素子１では顕著な効果が得られないことが判る。特
に、上記（ｂ）（ｃ）の実施例における酸化スズ添加量
が２重量％以下の場合は、従来の酸化亜鉛よりなる半導
体式ガス検知素子と比べて、センサ出力の復帰時間、ウ
ォーミングアップ時間共にさほど短縮するには至らず、
（ｅ）（ｆ）の実施例における酸化スズ添加量が１０重
量％以上の場合は、半導体式ガス検知素子の特性は酸化
スズの特性が優勢になり被検知ガスに対する低感度化
や、ガス選択性の喪失が顕著となり、硫黄化合物を含む
被検知ガスを選択的に検知するという酸化亜鉛の特性が
なくなるという結果が示された。さらに、硫化水素など
の曝露により応答波形がディケイするという問題を生じ
る。From (a) to (f), the amount of tin oxide added to zinc oxide is 2% by weight or less, or 10% by weight.
It can be seen that the substrate-type semiconductor gas detection element 1 having the gas sensitive portion 2 as described above cannot obtain a remarkable effect. In particular, when the amount of tin oxide added in the examples of (b) and (c) is 2% by weight or less, both the recovery time of the sensor output and the warming-up time are higher than those of the conventional semiconductor gas detection element made of zinc oxide. It doesn't go down so much,
When the amount of tin oxide added in the examples of (e) and (f) is 10% by weight or more, the characteristics of the semiconductor-type gas detection element are predominantly the characteristics of tin oxide, and the sensitivity of the gas to be detected is lowered and the gas selection is reduced. It was shown that the loss of the property became remarkable, and the characteristic of zinc oxide that selectively detects the detected gas containing the sulfur compound disappeared. Further, there is a problem that the response waveform decays due to exposure to hydrogen sulfide or the like.
【００４６】これらより、酸化亜鉛に対する酸化スズ添
加量を２〜１０重量％としたガス感応部を有する半導体
式ガス検知素子とすることにより、上記種々の問題点を
解決できる半導体式ガス検知素子を提供することが可能
となるのである。From the above, a semiconductor-type gas detection element which can solve the above-mentioned various problems can be obtained by using a semiconductor-type gas detection element having a gas sensitive portion in which the amount of tin oxide added to zinc oxide is 2 to 10% by weight. It is possible to provide.
【００４７】[実施例２]上記実施例において、酸化亜鉛
の少なくとも１０重量％を超微粒子酸化亜鉛としたもの
を使用することも可能である。Example 2 In the above example, it is also possible to use ultrafine zinc oxide in which at least 10% by weight of zinc oxide is used.
【００４８】前記超微粒子酸化亜鉛は、金属亜鉛をガス
化（プラズマ化）し、同時に酸素を供給する気相法によ
り得ることができる。このようにして作製された超微粒
子酸化亜鉛は、各酸化亜鉛粒子の平均粒子径が５０ｎｍ
以下であり、通常の酸化亜鉛の平均粒子径よりも小さい
ことを特徴とする。The ultrafine zinc oxide can be obtained by a gas phase method in which metallic zinc is gasified (plasmaized) and oxygen is simultaneously supplied. The ultrafine zinc oxide produced in this way has an average particle diameter of each zinc oxide particle of 50 nm.
It is below, and is characterized by being smaller than the average particle diameter of normal zinc oxide.
【００４９】そして酸化スズ、超微粒子酸化亜鉛を、酸
化亜鉛に対してそれぞれ２〜１０、１０重量％の割合に
なるように混合してペーストを作製し、このペーストか
ら上述と同様の方法により作製されたガス感応部を有す
る基板型半導体式ガス検知素子を用いて特性を調べた。Then, tin oxide and ultrafine zinc oxide were mixed in proportions of 2 to 10 and 10% by weight relative to zinc oxide to prepare a paste, and the paste was prepared by the same method as described above. The characteristics were investigated by using a substrate type semiconductor gas sensing element having the gas sensing part.
【００５０】図２に（Ａ）従来の酸化スズを添加しない
酸化亜鉛よりなるガス感応部を有する基板型半導体式ガ
ス検知素子と、（Ｂ）本発明の酸化亜鉛に酸化スズ及び
超微粒子酸化亜鉛を添加したガス感応部を有する基板型
半導体式ガス検知素子とを用いて、０．０１ｐｐｍ、
０．１ｐｐｍ、１ｐｐｍ硫化水素をそれぞれ検知した場
合のガス応答特性を比較した結果を示す。FIG. 2 shows (A) a conventional substrate type semiconductor gas detecting element having a gas sensitive portion made of zinc oxide to which tin oxide is not added, and (B) tin oxide and ultrafine zinc oxide in addition to the zinc oxide of the present invention. And a substrate type semiconductor gas detection element having a gas sensitive portion containing 0.01 ppm,
The result of having compared the gas response characteristic at the time of respectively detecting 0.1 ppm and 1 ppm hydrogen sulfide is shown.
【００５１】通常、電源印加後に被検知ガスを測定する
前に、センサ出力が安定するまでのウォーミングアップ
が必要とされる。前述したように、ウォーミングアップ
に要する時間とは、電源を印加してからガス検知可能な
状態になるまでの時間のことであり、具体的には、１週
間無通電放置（電源切った状態）の後、電源を印加して
からセンサ出力が０．０１ｐｐｍ硫化水素に対する出力
の１／２の出力に達するのに要した時間のことである。
（Ａ）の従来の基板型半導体式ガス検知素子におけるウ
ォーミングアップに要する時間は、センサ出力が図２中
のＡ１に達するのに要した時間であり、約３０分であっ
た。一方、（Ｂ）の本発明の基板型半導体式ガス検知素
子におけるウォーミングアップに要する時間は、センサ
出力が図２中のＢ１に達するのに要した時間であり、約
３分であった。Normally, warming up is required until the sensor output stabilizes before measuring the gas to be detected after the power is applied. As described above, the time required for warming up is the time from the application of power to the state in which gas detection is possible. Specifically, the time required for one week without power (power off) After that, it is the time required for the sensor output to reach 1/2 of the output with respect to 0.01 ppm hydrogen sulfide after the power is applied.
The time required for warming up in the conventional substrate type semiconductor gas detecting element of (A) is the time required for the sensor output to reach A1 in FIG. 2, which was about 30 minutes. On the other hand, the time required for warming up in the substrate type semiconductor gas detecting element of the present invention of (B) is the time required for the sensor output to reach B1 in FIG. 2, which was about 3 minutes.
【００５２】つまり、上記実施例１（ｃ）で示したよう
に、酸化亜鉛に酸化スズを２〜１０重量％添加すること
により、ウォーミングアップに要する時間は約３０分か
ら６分にまで短縮されているのに対して、本実施例２の
ように酸化亜鉛の１０重量％を超微粒子酸化亜鉛とする
ことにより、さらに半分の３分にまで短縮することが可
能になることが判明した。That is, as shown in Example 1 (c), by adding 2 to 10% by weight of tin oxide to zinc oxide, the time required for warming up is shortened from about 30 minutes to 6 minutes. On the other hand, it was found that by using 10% by weight of zinc oxide as ultrafine zinc oxide as in Example 2, it was possible to further reduce the time to half, which is 3 minutes.
【００５３】これは、超微粒子酸化亜鉛を用いることに
より酸化亜鉛全体の比表面積が大きくなり、その結果酸
化亜鉛と酸化スズとの接触面積が増し、酸化スズ添加の
効果が増したと考えられる。It is considered that by using ultrafine zinc oxide, the specific surface area of the whole zinc oxide was increased, and as a result, the contact area between zinc oxide and tin oxide was increased and the effect of tin oxide addition was increased.
【００５４】[実施例３]上記実施例において、前記ガス
感応部２に、Ｐｂ，Ｃｕ，Ｆｅ，Ｎｉ，Ｃｏの金属酸化
物のうち少なくとも一種を担持させることが可能であ
る。[Embodiment 3] In the above embodiment, the gas sensitive portion 2 can be made to carry at least one of the metal oxides of Pb, Cu, Fe, Ni and Co.
【００５５】例えば、前記酸化亜鉛に対して前記酸化ス
ズを５重量％混合して水で練って得られた前記酸化亜鉛
と前記酸化スズの混合物ペーストを、前記素子基体の白
金電極４ａ〜４ｂを覆うように塗布し、乾燥後、９００
℃で２時間焼成することにより、酸化亜鉛および酸化ス
ズの混合物からなる金属酸化物半導体を得る。For example, a mixture paste of the zinc oxide and the tin oxide obtained by mixing 5% by weight of the tin oxide with the zinc oxide and kneading with water is used to form the platinum electrodes 4a-4b of the element substrate. Apply to cover and dry, then 900
A metal oxide semiconductor made of a mixture of zinc oxide and tin oxide is obtained by baking at 2 ° C. for 2 hours.
【００５６】この金属酸化物半導体に、Ｐｂ，Ｃｕ，Ｆ
ｅ，Ｎｉ，Ｃｏの金属塩水溶液のうち少なくとも一種に
含浸、乾燥、６００℃で２時間焼成することにより、少
なくとも一種のPb、Cu、Fe、Ni、Coの金属酸化物を担持
した金属酸化物半導体をガス感応部２とする基板型半導
体式ガス検知素子１を得ることができる。Pb, Cu, F are added to this metal oxide semiconductor.
A metal oxide carrying at least one metal oxide of Pb, Cu, Fe, Ni, and Co by impregnating at least one of e, Ni, and Co metal salt aqueous solution, drying, and baking at 600 ° C. for 2 hours. It is possible to obtain the substrate-type semiconductor gas detection element 1 using the semiconductor as the gas sensitive section 2.
【００５７】この基板型半導体式ガス検知素子１の諸特
性（ガス検知時の応答時間、被検知ガス中から清浄空気
に戻した時のセンサ出力の復帰時間、ウォーミングアッ
プ時間）を調べた。尚、以下に示すデータは、前記基板
型半導体式ガス検知素子１を１０個作製し、それぞれの
基板型半導体式ガス検知素子１を使用して測定した結果
得られたデータの平均値を示したものである。Various characteristics of the substrate-type semiconductor gas detecting element 1 (response time at the time of gas detection, sensor output recovery time when returning from the gas to be detected to clean air, warming-up time) were examined. The data shown below are the average values of the data obtained as a result of measuring ten substrate type semiconductor gas detecting elements 1 and using each of the substrate type semiconductor gas detecting elements 1. It is a thing.
【００５８】（ａ）ガス検知時の応答時間
表７に、担持させる金属酸化物（Ｐｂ，Ｃｕ，Ｆｅ，Ｎ
ｉ，Ｃｏ）を種々変更して作製したガス感応部２を有す
る基板型半導体式ガス検知素子１を用いて、１ｐｐｍの
硫化水素に対する９０％応答時間を調べた結果を示し
た。(A) Response time at gas detection Table 7 shows the metal oxides (Pb, Cu, Fe, N) to be supported.
i, Co) was variously changed, and the 90% response time to 1 ppm of hydrogen sulfide was examined by using the substrate type semiconductor gas detection element 1 having the gas sensitive section 2.
【００５９】[0059]
【表７】 [Table 7]
【００６０】この結果より、何れの金属酸化物を用いた
場合においても、ガス感応部２に金属酸化物を担持させ
ない場合と比較すると、９０％応答時間は２／５〜４／
５に短縮されることが判明した。From these results, it can be seen that no matter which metal oxide is used, the 90% response time is 2/5 to 4 / when compared with the case where no metal oxide is supported on the gas sensitive part 2.
It turned out to be shortened to 5.
【００６１】（ｂ）被検知ガス中から清浄空気に戻した
時のセンサ出力の復帰時間
表８に、担持させる金属酸化物（Ｐｂ，Ｃｕ，Ｆｅ，Ｎ
ｉ，Ｃｏ）を種々変更して作製したガス感応部２を有す
る基板型半導体式ガス検知素子１を用いて、１ｐｐｍ硫
化水素曝露後、０．０１ｐｐｍ硫化水素に相当する出力
レベルまで復帰する時間（復帰時間）を調べた結果を示
した。(B) Recovery time of sensor output when returning to the clean air from the gas to be detected Table 8 shows the metal oxides (Pb, Cu, Fe, N) to be carried.
(i, Co) is variously changed, and the substrate-type semiconductor gas detection element 1 having the gas sensitive portion 2 is used to return to an output level equivalent to 0.01 ppm hydrogen sulfide after exposure to 1 ppm hydrogen sulfide ( The result of examining the recovery time) is shown.
【００６２】[0062]
【表８】 [Table 8]
【００６３】この結果より、何れの金属酸化物を用いた
場合においても、ガス感応部２に金属酸化物を担持させ
ない場合と比較すると、復帰時間は１／２〜４／５に短
縮されることが判明した。From these results, the recovery time can be shortened to 1/2 to 4/5 with any metal oxide as compared with the case where no metal oxide is supported on the gas sensitive part 2. There was found.
【００６４】（ｃ）ウォーミングアップ時間
表９に、担持させる金属酸化物（Ｐｂ，Ｃｕ，Ｆｅ，Ｎ
ｉ，Ｃｏ）を種々変更して作製したガス感応部２を有す
る基板型半導体式ガス検知素子１を用いて、ウォーミン
グアップに要する時間を調べた結果を示した。(C) Warming-up time Table 9 shows the metal oxides (Pb, Cu, Fe, N) to be supported.
i, Co) was variously changed, and the substrate-type semiconductor gas detection element 1 having the gas sensitive portion 2 was used to show the results of examining the time required for warming up.
【００６５】[0065]
【表９】 [Table 9]
【００６６】この結果より、何れの金属酸化物を用いた
場合においても、ガス感応部２に金属酸化物を担持させ
ない場合と比較すると、ウォーミングアップ時間は１／
２〜５／６に短縮されることが判明した。From these results, it can be seen that the warming-up time is 1 / (mm), whichever metal oxide is used, as compared with the case where no metal oxide is supported on the gas sensitive part 2.
It was found to be shortened to 2 to 5/6.
【００６７】以上の結果より、少なくとも一種のＰｂ，
Ｃｕ，Ｆｅ，Ｎｉ，Ｃｏの金属酸化物を担持した金属酸
化物半導体をガス感応部２とする基板型半導体式ガス検
知素子１の諸特性（ガス検知時の応答時間、被検知ガス
中から清浄空気に戻した時のセンサ出力の復帰時間、ウ
ォーミングアップ時間）は、ガス感応部２に金属酸化物
を担持させない場合と比較すると向上し、特に、Ｐｂ，
Ｃｕの金属酸化物の担持が効果的であることが判明し
た。このメカニズムは不明であるが、Ｐｂ，Ｃｕ，Ｆ
ｅ，Ｎｉ，Ｃｏの金属はいずれも硫化物をつくり易く、
Ｐｂ，Ｃｕ，Ｆｅ，Ｎｉ，Ｃｏの金属酸化物も硫黄化合
物を含む悪臭に対し高活性であると考えられる。このた
め硫黄化合物に対する反応が速く進み、ガス検知時の応
答、清浄空気に戻した時の復帰を速くすることができ、
また、ウォーミングアップ時間を短縮することもできた
と考えられる。From the above results, at least one Pb,
Various characteristics of the substrate-type semiconductor gas detection element 1 having a metal oxide semiconductor supporting a metal oxide of Cu, Fe, Ni, Co as the gas sensitive part 2 (response time at gas detection, cleaning from detected gas) The recovery time of the sensor output when returning to air, warming-up time) is improved compared to the case where no metal oxide is supported on the gas sensitive section 2, and in particular, Pb,
It has been found that the support of Cu metal oxide is effective. This mechanism is unknown, but Pb, Cu, F
The metals e, Ni, and Co all easily form sulfides,
It is considered that the metal oxides of Pb, Cu, Fe, Ni and Co are also highly active against malodors containing sulfur compounds. For this reason, the reaction to sulfur compounds progresses rapidly, and the response at the time of gas detection and the return when returned to clean air can be made faster,
It is also considered that the warm-up time could be shortened.
【図１】本発明の基板型半導体式ガス検知素子の概略図FIG. 1 is a schematic view of a substrate type semiconductor gas detection element of the present invention.
【図２】酸化亜鉛よりなるガス感応部を有する基板型半
導体式ガス検知素子と、酸化亜鉛に酸化スズ及び超微粒
子酸化亜鉛を添加したガス感応部を有する基板型半導体
式ガス検知素子とのガス応答特性を比較した図。FIG. 2 Gas of a substrate type semiconductor gas detecting element having a gas sensitive portion made of zinc oxide and a substrate type semiconductor gas detecting element having a gas sensitive portion obtained by adding tin oxide and ultrafine zinc oxide to zinc oxide The figure which compared the response characteristic.
１ 基板型半導体式ガス検知素子 ２ ガス感応部 ３ アルミナ基板 ４ａ〜４ｂ 白金電極 ５ ヒータ 1 Substrate type semiconductor gas detector 2 Gas sensitive section 3 Alumina substrate 4a-4b Platinum electrode 5 heater
フロントページの続き Ｆターム(参考） 2G046 AA02 AA04 AA11 AA13 AA15 AA18 AA19 AA24 AA25 AA26 BA01 BA09 BB02 BB04 BC05 BE03 EA04 FB02 FE03 FE09 FE11 FE12 FE25 FE28 FE31 FE39 FE48 Continued front page F-term (reference) 2G046 AA02 AA04 AA11 AA13 AA15 AA18 AA19 AA24 AA25 AA26 BA01 BA09 BB02 BB04 BC05 BE03 EA04 FB02 FE03 FE09 FE11 FE12 FE25 FE28 FE31 FE39 FE48
Claims (4)
半導体ペーストを焼成して作製した感応部を有する半導
体式ガス検知素子であって、 前記金属酸化物半導体ペーストが、前記酸化亜鉛粒子に
対して酸化スズ粒子を２〜１０重量％含む半導体式ガス
検知素子。1. A semiconductor-type gas detection element having a sensitive part, which is produced by firing a metal oxide semiconductor paste containing zinc oxide particles as a main component, wherein the metal oxide semiconductor paste is added to the zinc oxide particles. On the other hand, a semiconductor gas detection element containing 2 to 10% by weight of tin oxide particles.
％が超微粒子酸化亜鉛である請求項１に記載の半導体式
ガス検知素子。2. The semiconductor gas detecting element according to claim 1, wherein at least 10% by weight of the zinc oxide particles is ultrafine zinc oxide.
属亜鉛に酸素を供給して製造されたものである請求項２
に記載の半導体式ガス検知素子。3. The ultrafine zinc oxide is produced by supplying oxygen to gasified metallic zinc.
The semiconductor type gas detection element described in 1.
ｉ，Ｃｏの金属酸化物のうち少なくとも一種を担持させ
てある請求項１〜３に記載の半導体式ガス検知素子。4. The sensitive portion comprises Pb, Cu, Fe, N
The semiconductor gas detection element according to claim 1, wherein at least one of metal oxides of i and Co is supported.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002068384A JP3933500B2 (en) | 2002-03-13 | 2002-03-13 | Semiconductor gas detector |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005265548A (en) * | 2004-03-17 | 2005-09-29 | Tdk Corp | Gas sensor |
| JP2005315874A (en) * | 2004-04-02 | 2005-11-10 | New Cosmos Electric Corp | Gas sensor chip and manufacturing method therefor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51132889A (en) * | 1975-05-14 | 1976-11-18 | Toshiba Corp | Gas sensitive body |
| JPS5736807A (en) * | 1980-08-15 | 1982-02-27 | Tokyo Shibaura Electric Co | |
| JPH0815200A (en) * | 1994-06-28 | 1996-01-19 | Dkk Corp | Gas sensor for detecting quality of food |
-
2002
- 2002-03-13 JP JP2002068384A patent/JP3933500B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51132889A (en) * | 1975-05-14 | 1976-11-18 | Toshiba Corp | Gas sensitive body |
| JPS5736807A (en) * | 1980-08-15 | 1982-02-27 | Tokyo Shibaura Electric Co | |
| JPH0815200A (en) * | 1994-06-28 | 1996-01-19 | Dkk Corp | Gas sensor for detecting quality of food |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005265548A (en) * | 2004-03-17 | 2005-09-29 | Tdk Corp | Gas sensor |
| JP2005315874A (en) * | 2004-04-02 | 2005-11-10 | New Cosmos Electric Corp | Gas sensor chip and manufacturing method therefor |
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| Publication number | Publication date |
|---|---|
| JP3933500B2 (en) | 2007-06-20 |
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