JPH06128721A - Formation of sensitive thin film for gaseous nitrogen oxide sensor - Google Patents
Formation of sensitive thin film for gaseous nitrogen oxide sensorInfo
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- JPH06128721A JPH06128721A JP27964092A JP27964092A JPH06128721A JP H06128721 A JPH06128721 A JP H06128721A JP 27964092 A JP27964092 A JP 27964092A JP 27964092 A JP27964092 A JP 27964092A JP H06128721 A JPH06128721 A JP H06128721A
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- thin film
- sensitive thin
- sensitive
- forming
- film
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、窒素酸化物（ＮＯx と
略記する）ガス選択吸着分子を感応薄膜として用いたＮ
Ｏx ガスセンサ用の感応薄膜の形成方法に関するもので
ある。BACKGROUND OF THE INVENTION The present invention relates to N using a nitrogen oxide (abbreviated as NOx) gas selective adsorption molecule as a sensitive thin film.
The present invention relates to a method for forming a sensitive thin film for an Ox gas sensor.
【０００２】[0002]
【従来の技術】従来、ガスセンサ用の感応薄膜の形成方
法には、有機分子を真空蒸着する方法あるいはラングミ
ュアー―ブロジェット（ＬＢ）法が用いられてきた。図
８(ａ)〜(ｃ)は、例えば電気化学, 46, 597 (1978)に示
されたガスセンサ用の感応薄膜の形成プロセスを工程順
に示す断面模式図である。 図８において、１は薄膜を
形成する基板、２８はこの基板上に真空蒸着法を用いて
形成された厚さ約 0.4ミクロンの金属フタロシアニン薄
膜である。2. Description of the Related Art Conventionally, as a method for forming a sensitive thin film for a gas sensor, a method of vacuum-depositing organic molecules or a Langmuir-Blodgett (LB) method has been used. 8A to 8C are schematic cross-sectional views showing, in the order of steps, a process of forming a sensitive thin film for a gas sensor shown in, for example, Electrochemistry, 46 , 597 (1978). In FIG. 8, 1 is a substrate on which a thin film is to be formed, and 28 is a metal phthalocyanine thin film having a thickness of about 0.4 micron formed on this substrate by vacuum deposition.
【０００３】図８に示した従来のガスセンサ用感応薄膜
の形成プロセスでは、図８(ａ)に示す平滑な石英基板１
上にパイレックスガラス製るつぼに入れた金属フタロシ
アニン錯体をタングステン製ヒータで加熱して約 0.4ミ
クロンの厚さに蒸着して薄膜２８とする（図８(ｂ)）。
さらにこの膜２８のセンサ感度向上のために 350℃で４
時間熱アニーリングを行い（図８(ｃ)）、この薄膜２８
上に金蒸着膜を電極として形成しガスセンサ部としてい
る。この例では、薄膜２８上に気体分子が吸着すること
により生じる電気伝導度の変化を測定することでガスセ
ンサとしている。In the conventional process for forming a sensitive thin film for a gas sensor shown in FIG. 8, a smooth quartz substrate 1 shown in FIG.
A metal phthalocyanine complex placed in a Pyrex glass crucible is heated by a heater made of tungsten and evaporated to a thickness of about 0.4 μm to form a thin film 28 (FIG. 8B).
Furthermore, in order to improve the sensor sensitivity of this film 28
Thermal annealing is performed for a time (FIG. 8C), and the thin film 28 is formed.
A gold vapor deposition film is formed as an electrode on the top to form a gas sensor portion. In this example, a gas sensor is obtained by measuring a change in electrical conductivity caused by adsorption of gas molecules on the thin film 28.
【０００４】さらに、Thin Solid Films, Vol.180, 193
(1989) に示されたように水晶振動子上にプロピル置換
スクエアリリウム色素とアラキン酸カドミウムとの１：
１混合物をラングミュアー―ブロージェット（ＬＢ）法
を用いて薄膜化し、ガスセンサとして用いている例もあ
る。この例では、薄膜へのＮＯ2 分子の吸着により起こ
るプロピル置換スクエアリリウム色素にみられる蛍光強
度の変化と水晶振動子の周波数の変化を検知することで
ＮＯ2 ガスセンサとしている。Further, Thin Solid Films, Vol.180, 193
(1989), a propyl-substituted squarylium dye and cadmium arachiate on a quartz crystal were 1:
There is also an example in which one mixture is made into a thin film using the Langmuir-Blowjet (LB) method and used as a gas sensor. In this example, a NO 2 gas sensor is used by detecting a change in fluorescence intensity observed in a propyl-substituted squarylium dye caused by adsorption of NO 2 molecules on a thin film and a change in frequency of a crystal oscillator.
【０００５】[0005]
【発明が解決しようとする課題】上記のような従来のガ
スセンサ用感応薄膜の形成方法では、熱アニーリング以
外の薄膜表面状態の制御がなされていなかったので、薄
膜表面が全体に平坦で表面積が大きくならず、ガス分子
の吸着反応面積も小さいままであった。このような膜を
センサとして用いていたので、センサとしての重要な性
能である感度及び応答性が低いという問題点があった。In the conventional method of forming a sensitive thin film for gas sensor as described above, the surface state of the thin film other than thermal annealing is not controlled, so that the thin film surface is entirely flat and has a large surface area. Moreover, the adsorption reaction area of gas molecules remained small. Since such a film is used as a sensor, there is a problem that sensitivity and responsiveness, which are important performances as a sensor, are low.
【０００６】本発明は上記のような問題点を解消するた
めになされたもので、ＮＯx 選択吸着分子薄膜の表面に
凹凸を形成して、薄膜表面積を大きく増大させることに
より、ＮＯx 分子を広い濃度範囲で高い吸着能力と吸着
速度をもって吸着させることが可能となる窒素酸化物ガ
スセンサ用感応薄膜の形成方法を提供することを目的と
する。なお、この明細書における「凹凸を形成する」は
面を荒らす、粗面化することをも含む。The present invention has been made to solve the above-mentioned problems, and by forming irregularities on the surface of a NOx selective adsorption molecule thin film to greatly increase the thin film surface area, a wide range of NOx molecule concentration can be obtained. An object of the present invention is to provide a method for forming a sensitive thin film for a nitrogen oxide gas sensor, which is capable of adsorbing with a high adsorption capacity and adsorption rate in a range. It should be noted that in the present specification, "forming unevenness" includes roughening or roughening a surface.
【０００７】[0007]
【課題を解決するための手段】本発明の窒素酸化物ガス
センサ用感応薄膜の形成方法は、窒素酸化物ガスを選択
的に吸着する感応薄膜を成膜するに際し、上記感応薄膜
を形成する基板または下地薄膜に凹凸を形成し、成膜後
の上記感応薄膜の表面部に間接的に凹凸が形成されるよ
うにするものである。A method of forming a sensitive thin film for a nitrogen oxide gas sensor according to the present invention comprises a substrate on which the sensitive thin film is formed when forming a sensitive thin film that selectively adsorbs nitrogen oxide gas. The unevenness is formed on the underlying thin film so that the unevenness is indirectly formed on the surface portion of the sensitive thin film after the film formation.
【０００８】下地薄膜を粒径の制御が可能な化合物で形
成する、例えば弗化マグネシウム蒸着膜とする。The underlying thin film is formed of a compound whose grain size can be controlled, for example, a magnesium fluoride vapor deposition film.
【０００９】また、成膜後の感応薄膜の表面部に直接凹
凸を形成する。Further, the unevenness is directly formed on the surface portion of the sensitive thin film after the film formation.
【００１０】パターニングにより凹凸を形成する。Concavities and convexities are formed by patterning.
【００１１】さらに、感応薄膜成膜時に基板の温度を室
温以下の低温に保持するようにした。Further, the temperature of the substrate is kept at a low temperature below room temperature during the formation of the sensitive thin film.
【００１２】[0012]
【作用】本発明により形成されたＮＯx ガスセンサ用感
応薄膜は表面部に凹凸が形成されているので、従来ガス
センサに用いられてきた薄膜の表面構造と比較して、Ｎ
Ｏx ガス分子が吸着できる表面積が大きく増大するので
吸着能力が高まる。従ってガスセンサとしての重要な性
能である感度及び応答性が向上するとともに、検出濃度
範囲が広がる。Since the sensitive thin film for a NOx gas sensor formed according to the present invention has unevenness on the surface, it has an N-value lower than that of the thin film used in the conventional gas sensor.
Since the surface area where Ox gas molecules can be adsorbed is greatly increased, the adsorption capacity is enhanced. Therefore, the sensitivity and responsiveness, which are important performances of the gas sensor, are improved, and the detection concentration range is expanded.
【００１３】例えば弗化マグネシウム蒸着膜のように、
下地薄膜を粒径の制御が可能な化合物で形成することに
より、感応薄膜に容易に任意のサイズの凹凸を形成、任
意の面粗度に粗面化できる。For example, like a magnesium fluoride vapor deposition film,
By forming the underlying thin film with a compound whose grain size can be controlled, it is possible to easily form irregularities of any size on the sensitive thin film and roughen it to any surface roughness.
【００１４】さらに、基板の温度を室温以下の低温にす
ることにより分子の充填密度が減少することから、ガス
分子の薄膜内部への拡散が速やかとなり吸着速度が大き
くなるので、さらに感度、応答性及び検出濃度範囲が向
上する。Furthermore, since the packing density of molecules is reduced by lowering the temperature of the substrate below room temperature, the diffusion of gas molecules into the thin film is accelerated and the adsorption rate is increased, so that the sensitivity and responsiveness are further increased. And the detection concentration range is improved.
【００１５】[0015]
実施例１．以下、本発明の一実施例について具体的に説
明する。図１(ａ)〜(ｃ)の断面模式図に本発明の一実施
例のＮＯx ガス選択吸着分子としてテトラフェニルポル
フィリンルテニウムジピリジン錯体を用いた薄膜の形成
プロセスを工程順に示す。図１において、１は感応薄膜
を形成する基板、２は下地薄膜の弗化マグネシウム蒸着
膜、３はＮＯx ガス選択吸着分子からなる感応薄膜、テ
トラフェニルポルフィリンルテニウムジピリジン錯体の
蒸着膜である。Example 1. An embodiment of the present invention will be specifically described below. 1 (a) to 1 (c) are schematic sectional views showing, in order of steps, a thin film forming process using a tetraphenylporphyrin ruthenium dipyridine complex as a NOx gas selective adsorption molecule according to an embodiment of the present invention. In FIG. 1, 1 is a substrate on which a sensitive thin film is formed, 2 is a magnesium fluoride vapor deposition film as a base thin film, 3 is a sensitive thin film composed of NOx gas selective adsorption molecules, and a vapor deposition film of tetraphenylporphyrin ruthenium dipyridine complex.
【００１６】この薄膜形成プロセスにおいては、予め基
板１上に弗化マグネシウムの薄膜２を真空蒸着法を用い
て、50Å/minの条件で膜厚 0.5μｍ、平均粒径1000Åの
薄膜として形成しておく。この膜２上にＮＯx ガス選択
吸着分子であるテトラフェニルポルフィリンルテニウム
ジピリジン錯体を真空蒸着法を用いて、約 450℃で20Å
/minのレートで1000Å蒸着し感応薄膜３とした。In this thin film forming process, a thin film 2 of magnesium fluoride is previously formed on the substrate 1 by a vacuum deposition method as a thin film having a film thickness of 0.5 μm and an average particle size of 1000 Å under the condition of 50 Å / min. deep. A tetraphenylporphyrin ruthenium dipyridine complex, which is a NOx gas selective adsorption molecule, is deposited on this film 2 at about 450 ° C. for 20Å using a vacuum deposition method.
The sensitive thin film 3 was formed by depositing 1000 Å at a rate of / min.
【００１７】上記の薄膜形成プロセスを用いた場合、表
面構造の制御のために下地薄膜として形成した弗化マグ
ネシウムの蒸着膜２がかなり凸凹しているので、その上
に蒸着した選択吸着分子の感応薄膜２表面の構造も下地
の構造に依存して凸凹となっている。一方、従来法と同
じく蒸着による膜形成後に250℃で４時間熱アニーリン
グ処理を行ったルテニウム錯体薄膜表面は、図８に示し
たのと同様の構造をしており、あまり凸凹していない。
この結果、薄膜の表面積は本実施例の図１の形成プロセ
スを用いたほうがはるかに大きくなっている。When the above-mentioned thin film forming process is used, the vapor deposition film 2 of magnesium fluoride formed as a base thin film for controlling the surface structure is considerably uneven, and therefore, the reaction of the selectively adsorbed molecules vapor-deposited thereon is caused. The structure of the surface of the thin film 2 is also uneven depending on the structure of the base. On the other hand, the ruthenium complex thin film surface, which was subjected to the thermal annealing treatment at 250 ° C. for 4 hours after the film formation by vapor deposition as in the conventional method, has a structure similar to that shown in FIG. 8 and is not so rough.
As a result, the surface area of the thin film is much larger when the forming process of this embodiment shown in FIG. 1 is used.
【００１８】上記のプロセスにより形成した感応薄膜を
用いてＮＯ2 ガスの吸着特性を調べた。図２に本発明の
一実施態様である差動方式を用いたＮＯx ガスセンサー
システムの構成図を示す。図において、４はＡＴカット
で ９MHzを基本周波数とする水晶振動子であり、５はＮ
Ｏ2 ガスに対して選択吸着を示さない中心金属なしのテ
トラフェニルポルフィリンの薄膜、６は発振回路、７は
周波数カウンター、８は水晶振動子４を保持したガス流
入装置、９は水晶振動子４の周波数差を演算する周波数
差演算装置である。The adsorption characteristics of NO 2 gas were examined using the sensitive thin film formed by the above process. FIG. 2 shows a block diagram of a NOx gas sensor system using a differential system which is an embodiment of the present invention. In the figure, 4 is an AT cut crystal unit with a fundamental frequency of 9 MHz, and 5 is N
A central metal-free thin film of tetraphenylporphyrin that does not show selective adsorption to O 2 gas, 6 is an oscillation circuit, 7 is a frequency counter, 8 is a gas inflow device holding a crystal oscillator 4, and 9 is a crystal oscillator 4. It is a frequency difference calculation device for calculating the frequency difference.
【００１９】この実施態様においては水晶振動子４上に
前項と同じ条件で、下地の弗化マグネシウム蒸着膜２上
に形成したテトラフェニルポルフィリンルテニウムジピ
リジン錯体の感応薄膜３をガスセンサとしている。これ
をガス流入装置８に設置し、発振回路６により水晶振動
子４を発振させ、混合ガス流入後の水晶振動子４の周波
数変化を周波数カウンター７で計測するようにした実験
装置である。この装置においては、水晶振動子４上の感
応薄膜３にガス中の気体分子が吸着すると薄膜３の質量
がその分だけ増加する。水晶振動子４は質量の増加に対
応して発振周波数が減少するため、この周波数の減少に
よって吸着分子の質量即ち濃度を測定することが可能と
なる。さらにこのシステムにおいては、ＮＯ2 選択吸着
分子薄膜である感応薄膜３へのＮＯ2 以外のガス種の吸
着による周波数の減少に対しては、選択吸着分子と同程
度の吸着能をもつ薄膜５を形成した水晶振動子４を設置
し、２つの発振周波数の差を周波数演算装置９で計算可
能にしていることから、ＮＯ2 以外のガス種の吸着によ
る水晶振動子４の周波数減少分を２つの水晶振動子４の
周波数差を計測（差動方式）することで相殺し、ＮＯ2
ガスをＳ／Ｎ比と選択性良く計測できるように工夫して
ある。また水晶振動子４の周波数変化は極微小の質量変
化にも敏感であるため、極めて低濃度の測定に用いるこ
とができる。In this embodiment, the sensitive thin film 3 of the tetraphenylporphyrin ruthenium dipyridine complex formed on the underlying magnesium fluoride vapor-deposited film 2 is used as a gas sensor under the same conditions as above on the quartz oscillator 4. This is an experimental device in which this is installed in the gas inflow device 8, the crystal oscillator 4 is oscillated by the oscillation circuit 6, and the frequency change of the crystal oscillator 4 after the inflow of the mixed gas is measured by the frequency counter 7. In this device, when gas molecules in the gas are adsorbed on the sensitive thin film 3 on the crystal oscillator 4, the mass of the thin film 3 increases by that amount. Since the oscillation frequency of the crystal oscillator 4 decreases as the mass increases, it becomes possible to measure the mass of the adsorbed molecules, that is, the concentration, by decreasing the frequency. Further, in this system, a thin film 5 having an adsorption capacity similar to that of the selective adsorption molecule is used to reduce the frequency due to adsorption of a gas species other than NO 2 to the sensitive thin film 3 which is the NO 2 selective adsorption molecule thin film. Since the formed crystal unit 4 is installed and the difference between the two oscillation frequencies can be calculated by the frequency calculation device 9, the frequency reduction amount of the crystal unit 4 due to the adsorption of the gas species other than NO 2 is set to two. It is canceled by measuring the frequency difference of the crystal unit 4 (differential method), and NO 2
It is devised so that the gas can be measured with good S / N ratio and selectivity. Further, since the frequency change of the crystal unit 4 is sensitive to the minute change in mass, it can be used for the measurement of extremely low concentration.
【００２０】本センサを設置したガス流入実験装置８に
アルゴンをベースとし、酸素、二酸化炭素、窒素、水
素、メタン及び二酸化窒素をそれぞれ１００ppm 含む混
合ガスを、２５℃常圧で１００ml／min の流量で１０mi
n 流入させ、ガス接触による感応薄膜３への二酸化窒素
の吸着特性を調べた。混合ガスを流入させると、水晶振
動子４の周波数差は、図３の特性図に示すように増加し
た。縦軸は周波数差Δｆ(Ｈｚ)、横軸は時間(min )を示
し、特性曲線ａがこの実施例の感応薄膜（弗化マグネシ
ウム蒸着膜上に形成したテトラフェニルポルフィリンル
テニウムジピリジン錯体の蒸着薄膜）のＮＯ2 ガスに対
する周波数応答曲線を、特性曲線ｂが比較例の感応薄膜
（従来法を用いて形成したテトラフェニルポルフィリン
ルテニウムジピリジン錯体の蒸着薄膜）のＮＯ2 ガスに
対する周波数応答曲線を表す。このときの周波数差の増
加は、ＮＯ2 選択吸着分子の感応薄膜に吸着したＮＯ2
分子数の増加に起因する。本実施例の応答曲線ａ及び従
来法の薄膜の応答曲線ｂを比較すると、本実施例の応答
曲線ａのほうが周波数差の変化量は、時間経過に対して
大きく、このことから選択吸着分子薄膜の表面積を増大
させたほうが、ＮＯ2分子を早くかつ多数吸着できるこ
とが確認された。The gas inflow experiment device 8 equipped with this sensor is based on argon and contains a mixed gas containing 100 ppm of oxygen, carbon dioxide, nitrogen, hydrogen, methane and nitrogen dioxide at a flow rate of 100 ml / min at 25 ° C. and normal pressure. At 10mi
Then, the adsorption characteristics of nitrogen dioxide on the sensitive thin film 3 by gas contact were investigated. When the mixed gas was flowed in, the frequency difference of the crystal unit 4 increased as shown in the characteristic diagram of FIG. The vertical axis represents the frequency difference Δf (Hz), the horizontal axis represents the time (min), and the characteristic curve a is the sensitive thin film of this example (a vapor-deposited thin film of a tetraphenylporphyrin ruthenium dipyridine complex formed on a magnesium fluoride vapor-deposited film). the frequency response curves for NO 2 gas), represents the frequency response curves for NO 2 gas sensitive film characteristic curve b is Comparative example (deposition film of tetraphenylporphyrin ruthenium di pyridine complex formed using conventional methods). Increase of the frequency difference at this time, NO 2 adsorbed on the sensitive film of NO 2 selective adsorption molecules
Due to the increase in the number of molecules. Comparing the response curve a of this example with the response curve b of the thin film of the conventional method, the change amount of the frequency difference of the response curve a of this example is larger with the passage of time. It was confirmed that the NO 2 molecules could be adsorbed quickly and in large numbers by increasing the surface area of NO 2 .
【００２１】また１ppmの濃度の二酸化窒素を含む混合
ガスで試験を行った場合も１００ppmの場合と同様に２
つの感応薄膜での周波数差増加の挙動の違いが観察さ
れ、本実施例の下地に弗化マグネシウムの膜を形成して
凹凸を形成した感応薄膜を用いたガスセンサのほうが応
答速度および感度ともに優っていた。Also, when a test is conducted with a mixed gas containing nitrogen dioxide at a concentration of 1 ppm, as in the case of 100 ppm, 2
A difference in the behavior of increasing the frequency difference between the two sensitive thin films was observed, and the gas sensor using the sensitive thin film in which the magnesium fluoride film was formed on the base of this example was superior in both response speed and sensitivity. It was
【００２２】実施例２．図４に本発明の他の実施態様で
ある電気伝導方式を用いたＮＯx ガスセンサーシステム
の構成図を示す。図において、１２は本実施例２でＮＯ
x 選択吸着分子として銅フタロシアニン錯体を用いた感
応薄膜、１３は交流電源、１４は金電極、１５は基準抵
抗、１６は電流・電圧計、１７は記録計、１８はガス流
入装置である。Example 2. FIG. 4 is a block diagram of a NOx gas sensor system using an electric conduction system according to another embodiment of the present invention. In the figure, 12 is NO in the second embodiment.
x A sensitive thin film using a copper phthalocyanine complex as a selective adsorption molecule, 13 is an AC power source, 14 is a gold electrode, 15 is a reference resistance, 16 is an ammeter / voltmeter, 17 is a recorder, and 18 is a gas inflow device.
【００２３】この装置においては、基板１上に実施例１
と同じプロセスを用いて形成した下地の弗化マグネシウ
ム膜上に感応薄膜の銅フタロシアニンの真空蒸着膜１２
を約1000Åの膜厚で形成した。更にその膜の上にマスク
をかけ金電極１４を約1000Å蒸着してガスセンサとし
た。これをガス流入装置１８に設置し、混合ガス流入後
の電気伝導度の変化を基準抵抗１５にかかる電圧変化と
して計測するようにした実験装置である。この装置にお
いては、基板１上のＮＯx 選択吸着分子薄膜（感応薄
膜）１２にガス中の気体分子が吸着すると吸着した分子
数に比例して薄膜１２の電導度が変化することから、ガ
ス中の特定分子の濃度を測定することが可能となる。In this device, the first embodiment is mounted on the substrate 1.
Vacuum-deposited copper phthalocyanine film 12 as a sensitive thin film on the underlying magnesium fluoride film formed by using the same process as described above.
Was formed with a film thickness of about 1000Å. Further, a mask was put on the film and a gold electrode 14 was vapor-deposited by about 1000 Å to obtain a gas sensor. This is an experimental device in which this is installed in the gas inflow device 18 and a change in electric conductivity after the inflow of the mixed gas is measured as a voltage change applied to the reference resistance 15. In this apparatus, when the NOx selective adsorption molecule thin film (sensitive thin film) 12 on the substrate 1 adsorbs gas molecules in the gas, the conductivity of the thin film 12 changes in proportion to the number of adsorbed molecules. It becomes possible to measure the concentration of a specific molecule.
【００２４】本センサを設置したガス流入実験装置１８
にアルゴンをベースとした酸素、二酸化炭素、窒素、水
素、メタン及び二酸化窒素をそれぞれ１００ppm 含む混
合ガスを、２５℃常圧で１００ml/minの流量で３min 流
入させ、ガス接触による感応薄膜への二酸化窒素の吸着
特性を調べた。その結果を図５の特性図に示す。縦軸は
電圧(Ｖ)、横軸は時間(min )を示し、特性曲線ｃがこの
実施例の感応薄膜（弗化マグネシウム蒸着膜上に形成し
た銅フタロシアニン錯体の蒸着薄膜）のＮＯ2ガスに対
する電気伝導特性の応答曲線、特性曲線ｄが比較例の感
応薄膜（従来法を用いて形成した銅フタロシアニン錯体
の蒸着薄膜）のＮＯ2 ガスに対する電気伝導特性の応答
曲線を表す。混合ガスを流入させると、伝導度は図５に
示すように上昇した。このときの伝導度の上昇は、ＮＯ
2 選択吸着分子に吸着したＮＯ2分子の増加に起因す
る。両者を比較すると電導度の増加は本実施例の応答曲
線ｃの方が従来法の応答曲線ｄより時間経過に対して大
きく、このことからも表面積を大きくした感応薄膜のほ
うが従来の感応薄膜と比べ、ＮＯ2 分子を早くかつ多数
吸着できることが確認された。Gas inflow experimental device 18 equipped with this sensor
A mixed gas containing 100 ppm each of oxygen, carbon dioxide, nitrogen, hydrogen, methane, and nitrogen dioxide based on argon is allowed to flow for 3 minutes at a flow rate of 100 ml / min at 25 ° C. and atmospheric pressure to oxidize the sensitive thin film by gas contact. The adsorption characteristics of nitrogen were investigated. The results are shown in the characteristic diagram of FIG. The vertical axis represents voltage (V), the horizontal axis represents time (min), and the characteristic curve c is for the NO 2 gas of the sensitive thin film (deposited thin film of copper phthalocyanine complex formed on the evaporated magnesium fluoride film) of this example. The response curve of the electric conduction characteristic and the characteristic curve d represent the response curve of the electric conduction characteristic of the sensitive thin film of Comparative Example (deposited thin film of copper phthalocyanine complex formed by the conventional method) to NO 2 gas. When the mixed gas was flowed in, the conductivity increased as shown in FIG. The increase in conductivity at this time is NO
This is due to an increase in NO 2 molecules adsorbed on the 2 selective adsorption molecules. Comparing the two, the increase of the conductivity is larger in the response curve c of this embodiment than in the response curve d of the conventional method over time. From this, the sensitive thin film having a large surface area is more effective than the conventional sensitive thin film. In comparison, it was confirmed that NO 2 molecules could be adsorbed quickly and in large numbers.
【００２５】また１ppmの濃度の二酸化窒素を含む混合
ガスで試験を行った場合も１００ppmの場合と同様に２
つの感応薄膜での電導度増加の挙動の違いが観察され、
本実施例の下地に弗化マグネシウムの膜を形成して凹凸
を形成した感応薄膜を用いたガスセンサのほうが応答速
度および感度ともに優っていた。Also, when the test is conducted with a mixed gas containing nitrogen dioxide at a concentration of 1 ppm, it is 2 as in the case of 100 ppm.
A difference in the behavior of the increase in conductivity between the two sensitive thin films was observed,
The gas sensor using the sensitive thin film in which the magnesium fluoride film was formed on the underlayer to form the unevenness in this example was superior in both response speed and sensitivity.
【００２６】実施例３．図６(ａ)〜(ｄ)の断面模式図に
本発明の他の実施例のＮＯx ガス選択吸着分子としてテ
トラフェニルポルフィリンルテニウムジピリジン錯体を
用いた感応薄膜の形成プロセスを工程順に示す。図６
(ｅ)の平面図に得られた感応薄膜の凹凸パターンを示
す。図において、２１は感応薄膜３のパターニング処理
をするために用いたマスクで、この場合は約１μｍピッ
チの格子状パターンを用いた。２２は感応（選択吸着分
子）薄膜３上にマスク２１を介して蒸着した金属アルミ
ニウム薄膜である。Example 3. FIGS. 6A to 6D are schematic sectional views showing a process of forming a sensitive thin film using a tetraphenylporphyrin ruthenium dipyridine complex as a NOx gas selective adsorption molecule according to another embodiment of the present invention in the order of steps. Figure 6
The plan view of (e) shows the concavo-convex pattern of the obtained sensitive thin film. In the figure, reference numeral 21 is a mask used for patterning the sensitive thin film 3, and in this case, a grid pattern having a pitch of about 1 μm was used. Reference numeral 22 is a metal aluminum thin film deposited on the sensitive (selective adsorption molecule) thin film 3 through the mask 21.
【００２７】この薄膜形成プロセスにおいては、図６
(ａ)に示す基板１上にテトラフェニルポルフィリンルテ
ニウムジピリジン錯体からなる感応薄膜３を真空蒸着法
を用いて、約 450℃で50Å/minのレートで約１μｍの膜
厚で形成した（図６(ｂ)）。その後この感応薄膜３上に
予め作製しておいたマスク２１を介して金属アルミニウ
ム２２を約 100Å蒸着する（図６(ｃ)）。次に酸素プラ
ズマ中でこの膜をエッチング処理を行う。金属および有
機錯体のエッチング速度の違いにより、有機物、即ち感
応薄膜３のほうが速くエッチングされていく。金属アル
ミニウム薄膜２２のエッチングが終了したところで処理
を停止することにより、図６(ｄ)の断面構造を持ち、図
６(ｅ)の平面構造を持つ選択吸着分子薄膜を形成するこ
とができる。In this thin film forming process, as shown in FIG.
A sensitive thin film 3 made of a tetraphenylporphyrin ruthenium dipyridine complex was formed on a substrate 1 shown in (a) by a vacuum deposition method at a rate of 50 Å / min at a temperature of about 450 ° C. and a thickness of about 1 μm (FIG. 6). (b)). After that, about 100 liters of metallic aluminum 22 is vapor-deposited on the sensitive thin film 3 through a mask 21 which is prepared in advance (FIG. 6 (c)). Next, this film is etched in oxygen plasma. Due to the difference in etching rate between the metal and the organic complex, the organic substance, that is, the sensitive thin film 3 is etched faster. By stopping the process when the etching of the metal aluminum thin film 22 is completed, it is possible to form the selective adsorption molecule thin film having the sectional structure of FIG. 6D and the planar structure of FIG.
【００２８】本実施例においては、感応薄膜である選択
吸着分子薄膜の表面積を増加させるために、感応薄膜形
成後に上記に示したパターニング処理を行っていること
を特徴とし、図８の従来法の感応薄膜と比較してはるか
に表面積が大きくなっている。The present embodiment is characterized in that the above-mentioned patterning treatment is performed after the formation of the sensitive thin film in order to increase the surface area of the selective adsorption molecule thin film which is the sensitive thin film. The surface area is much larger than that of the sensitive thin film.
【００２９】このプロセス法を用いて水晶振動子上にテ
トラフェニルポルフィリンルテニウムジピリジンの感応
薄膜を形成後、実施例１と同じ図２に示す装置を用いて
同一条件で、ガス接触による感応薄膜への二酸化窒素の
吸着特性を調べたところ、同様の結果が得られた。この
ことから感応（選択吸着分子）薄膜のパターニング処理
により凹凸を形成し表面積を増加させたほうが、ＮＯ2
分子を早くかつ多数吸着することが確認された。After forming a sensitive thin film of tetraphenylporphyrin ruthenium dipyridine on a quartz oscillator by using this process method, a sensitive thin film by gas contact was formed under the same conditions using the same apparatus shown in FIG. 2 as in Example 1. When the adsorption property of nitrogen dioxide was examined, the same result was obtained. Better to increase the formed surface irregularities by patterning treatment of the sensitive (selective adsorption molecules) film from this is, NO 2
It was confirmed that molecules were adsorbed quickly and in large numbers.
【００３０】実施例４．実施例３と同じ条件で基板１上
に、銅フタロシアニンのパターニングした感応薄膜を作
製後、更にその感応薄膜の上に実施例２と同じ条件で金
電極を蒸着して図３に示すガスセンサを構成した。セン
サをガス流入実験装置１８に設置し、実施例２と同じ条
件でガス接触による感応薄膜への二酸化窒素の吸着特性
を調べたところ、同様の結果が得られた。このことから
もパターニング処理により凹凸を形成し表面積を大きく
した感応薄膜のほうが、従来の感応薄膜と比べＮＯ2 分
子を早くかつ多数吸着することが確認された。Example 4. After forming a sensitive thin film in which copper phthalocyanine was patterned on the substrate 1 under the same conditions as in Example 3, a gold electrode was further deposited on the sensitive thin film under the same conditions as in Example 2 to form the gas sensor shown in FIG. did. When the sensor was installed in the gas inflow experiment device 18 and the adsorption characteristics of nitrogen dioxide on the sensitive thin film by gas contact under the same conditions as in Example 2 were examined, similar results were obtained. From this, it was also confirmed that the sensitive thin film having the surface area increased by forming the unevenness by the patterning process adsorbs a large number of NO 2 molecules faster than the conventional sensitive thin film.
【００３１】実施例５．図７(ａ)〜(ｇ)の断面模式図に
本発明のさらに他の実施例のＮＯx ガス選択吸着分子と
してテトラフェニルポルフィリンルテニウムジピリジン
錯体を用いた感応薄膜の形成プロセスを工程順に示す。
図７(ｈ)の平面図に得られた感応薄膜の凹凸パターンを
示す。図において、２３は水晶基板、２４はフォトレジ
スト、２５はフォトマスク、２６は金蒸着膜、２７は電
極としての銀蒸着膜である。Example 5. 7 (a) to 7 (g) are schematic cross-sectional views showing a process of forming a sensitive thin film using a tetraphenylporphyrin ruthenium dipyridine complex as a NOx gas selective adsorption molecule according to still another embodiment of the present invention in the order of steps.
The concavo-convex pattern of the obtained sensitive thin film is shown in the plan view of FIG. In the figure, 23 is a quartz substrate, 24 is a photoresist, 25 is a photomask, 26 is a gold vapor deposition film, and 27 is a silver vapor deposition film as an electrode.
【００３２】この薄膜形成プロセスにおいては、図７
(ａ)に示す水晶基板２３上にフォトレジスト２４を形成
し（図７(ｂ)）。その後予め作製しておいたフォトマス
ク２５をかけてパターン（この場合は約１μｍピッチの
格子状パターン）を現像し（図７(ｃ)）、レジスト膜２
４パターンを有する水晶基板２３の上に金の蒸着膜２６
を形成し、レジスト剥離液によりレジスト２４部分を除
去すると水晶基板２３上に直接形成された金蒸着膜２６
の部分だけが残る（図７(ｄ)）。この金蒸着膜２６を有
する水晶基板２３を希弗酸中でエッチング処理すると、
金蒸着膜２６がある部分は保護され、水晶部、即ち水晶
基板２３だけがエッチングされる。目的の深さにまで水
晶がエッチングされたところで処理を停止し、ヨウ化カ
リウム溶液中で金蒸着膜２６を溶解させ（図７(ｅ)）、
その上から電極として用いる銀蒸着膜２７を形成し（図
７(ｆ)）、さらにその上に選択吸着分子からなる薄膜を
真空蒸着法を用いて形成することにより、図７(ｇ)に示
すような断面拡大構造と図７(ｈ)に示すような平面構造
をもつ感応薄膜３が作製できる。In this thin film forming process, as shown in FIG.
A photoresist 24 is formed on the quartz substrate 23 shown in (a) (FIG. 7 (b)). Thereafter, a photomask 25 prepared in advance is applied to develop the pattern (in this case, a grid pattern having a pitch of about 1 μm) (FIG. 7C), and the resist film 2
A vapor deposition film 26 of gold is formed on a quartz substrate 23 having four patterns.
And a portion of the resist 24 is removed by a resist stripping solution, the gold vapor deposition film 26 directly formed on the quartz substrate 23.
Only the part is left (Fig. 7 (d)). When the quartz substrate 23 having the gold deposited film 26 is etched in dilute hydrofluoric acid,
The portion where the gold vapor deposition film 26 is present is protected, and only the crystal portion, that is, the crystal substrate 23 is etched. The process is stopped when the crystal is etched to the target depth, and the gold vapor deposition film 26 is dissolved in the potassium iodide solution (FIG. 7 (e)).
A silver vapor-deposited film 27 used as an electrode is formed thereon (FIG. 7 (f)), and a thin film composed of selectively adsorbed molecules is further formed thereon by a vacuum vapor deposition method to obtain the result shown in FIG. 7 (g). A sensitive thin film 3 having such a cross-sectional enlarged structure and a planar structure as shown in FIG. 7 (h) can be manufactured.
【００３３】本実施例においては、選択吸着分子薄膜の
表面積を増加させるために、薄膜を形成する水晶基板２
４をパターニング処理し、凹凸を形成した後、選択吸着
分子からなる感応薄膜の形成を行っていることを特徴と
し、図８の従来法の薄膜と比較してはるかに表面積が大
きくなっている。In this embodiment, in order to increase the surface area of the selective adsorption molecule thin film, the quartz substrate 2 on which the thin film is formed is formed.
4 is patterned to form irregularities, and then a sensitive thin film composed of selectively adsorbed molecules is formed. The surface area is much larger than that of the conventional thin film shown in FIG.
【００３４】上記の薄膜形成プロセスを用いて微細加
工、銀電極を蒸着した水晶基板を水晶振動子とし、この
上にテトラフェニルポルフィリンルテニウムジピリジン
錯体の感応薄膜を形成した。実施例１と同じ図２に示す
装置を用いて同一条件で、ガス接触による感応薄膜への
二酸化窒素の吸着特性を調べたところ、実施例１と同様
の結果が得られた。このことから水晶基板のパターニン
グ処理により感応（選択吸着分子）薄膜に凹凸を形成
し、その表面積を増加させたもののほうが、ＮＯ2分子
を早くかつ多数吸着することが確認された。Using the above-mentioned thin film forming process, a quartz substrate on which fine processing and silver electrodes were deposited was used as a quartz oscillator, and a sensitive thin film of a tetraphenylporphyrin ruthenium dipyridine complex was formed thereon. When the adsorption characteristics of nitrogen dioxide on the sensitive thin film by gas contact were examined under the same conditions using the same apparatus as in Example 1 shown in FIG. 2, the same results as in Example 1 were obtained. From this, it was confirmed that the patterning treatment of the quartz substrate formed irregularities on the sensitive (selective adsorption molecule) thin film and increased the surface area thereof, adsorbed a large number of NO 2 molecules faster.
【００３５】実施例６．実施例５と同じ条件で水晶基板
上に、銅フタロシアニンの感応薄膜を作製後、更にその
膜の上に実施例２と同じ条件で金電極を蒸着して図３に
示すガスセンサを構成した。このセンサをガス流入実験
装置に設置し、実施例２と同じ条件でガス接触による感
応薄膜への二酸化窒素の吸着特性を調べたところ、同様
の結果が得られた。このことからも水晶基板のパターニ
ング処理により感応（選択吸着分子）薄膜の表面積を大
きくしたほうが、従来の薄膜と比べＮＯ2 分子を早くか
つ多数吸着することが確認された。Example 6. After forming a sensitive thin film of copper phthalocyanine on a quartz substrate under the same conditions as in Example 5, a gold electrode was further vapor-deposited on the film under the same conditions as in Example 2 to form the gas sensor shown in FIG. When this sensor was installed in a gas inflow experimental device and the adsorption characteristics of nitrogen dioxide on the sensitive thin film by gas contact under the same conditions as in Example 2 were examined, similar results were obtained. From this, it was also confirmed that the larger surface area of the sensitive (selective adsorption molecule) thin film by the patterning treatment of the quartz substrate adsorbs a large number of NO 2 molecules earlier than the conventional thin film.
【００３６】実施例７．実施例１で行った感応薄膜の形
成方法において、基板に下地の弗化マグネシウムを蒸着
した後、この基板の温度を―１１０℃に設定し、この温
度にした後テトラフェニルポルフィリンルテニウムジピ
リジン錯体の感応薄膜を形成した。本実施例では従来法
と比較して、表面積を増大させているとともに基板温度
を低温として薄膜形成を行っているので、感応薄膜の構
造が非晶質となる。さらに感応薄膜を構成する選択吸着
分子の充填密度も減少し、感応薄膜自身がポーラスにな
ることからＮＯ2 分子が膜内部まで高速で拡散吸着でき
る。Example 7. In the method of forming a sensitive thin film performed in Example 1, after depositing an underlying magnesium fluoride on a substrate, the temperature of this substrate was set to −110 ° C., and after this temperature was reached, tetraphenylporphyrin ruthenium dipyridine complex was formed. A sensitive thin film was formed. In this embodiment, compared with the conventional method, the surface area is increased and the substrate temperature is set to a low temperature to form the thin film, so that the structure of the sensitive thin film becomes amorphous. Further, the packing density of the selectively adsorbed molecules constituting the sensitive thin film also decreases, and the sensitive thin film itself becomes porous, so that NO 2 molecules can be diffused and adsorbed at high speed inside the film.
【００３７】この方法を用いて水晶振動子上にテトラフ
ェニルポルフィリンルテニウムジピリジン錯体の感応薄
膜を形成し、実施例１と同じ装置および同一条件で、ガ
ス接触による感応薄膜への二酸化窒素の吸着特性を調べ
たところ、吸着特性はさらに向上した。このことから感
応（選択吸着分子）薄膜の表面積を増加させ、さらに薄
膜を非晶質にしたほうが、ＮＯ2 分子を早くかつ多数吸
着することが確認された。By using this method, a sensitive thin film of a tetraphenylporphyrin ruthenium dipyridine complex was formed on a quartz oscillator, and the adsorption property of nitrogen dioxide to the sensitive thin film by gas contact was obtained by the same apparatus and conditions as in Example 1. Was examined, the adsorption property was further improved. From this, it was confirmed that increasing the surface area of the sensitive (selective adsorption molecule) thin film and further making the thin film amorphous adsorbs a large number of NO 2 molecules quickly.
【００３８】さらに、実施例２〜６の感応薄膜形成方法
を用いて薄膜を形成する際、本実施例を適用し同じく基
板の温度を―１１０℃という低温にして形成した。この
条件で薄膜を形成した後、実施例２〜６と同じ条件でガ
ス接触による二酸化窒素の吸着特性を調べたところ、い
ずれの場合にも従来法と比べ吸着特性が著しく向上して
いることが確認された。薄膜形成温度は低いほど充填密
度が減少するが、低すぎると成膜できなくなるので、−
５０〜−１５０℃の範囲が望ましい。Further, when a thin film was formed by using the method for forming a sensitive thin film of Examples 2 to 6, this example was applied and the temperature of the substrate was set to a low temperature of -110 ° C. After forming a thin film under these conditions, the adsorption characteristics of nitrogen dioxide by gas contact were examined under the same conditions as in Examples 2 to 6, and in any case, the adsorption characteristics were remarkably improved as compared with the conventional method. confirmed. The packing density decreases as the thin film formation temperature decreases, but if it is too low, the film cannot be formed.
The range of 50 to -150 ° C is desirable.
【００３９】なお上記実施例では、ＮＯ2 選択感応薄膜
材料としてテトラフェニルポルフィリンジピリジンルテ
ニウム錯体及び銅フタロシアニン錯体を例に説明した
が、これに限るものでなく、例えば他のポルフィリン錯
体、フタロシアニン錯体を用いてもよく、テトラフェニ
ルポルフィリンニッケル錯体、テトラフェニルポルフィ
リン鉄錯体、テトラフェニルポルフィリン銀錯体、テト
ラフェニルポルフィリンコバルト錯体、フタロシアニン
鉄錯体、フタロシアニン銅錯体、フタロシアニン鉛錯
体、フタロシアニンシリコン錯体などの有機分子、並び
に亜鉛の酸化物などの無機分子をＮＯ2 選択吸着分子と
して用いても同様の結果が得られた。また、ＮＯx 成分
として二酸化窒素を例に述べたが一酸化窒素、他の窒素
酸化物に対しても同様の効果を奏する。In the above embodiments, the tetraphenylporphyrin dipyridine ruthenium complex and the copper phthalocyanine complex were described as examples of the NO 2 selective sensitive thin film material, but the present invention is not limited to this, and other porphyrin complexes and phthalocyanine complexes may be used. May be used, tetraphenylporphyrin nickel complex, tetraphenylporphyrin iron complex, tetraphenylporphyrin silver complex, tetraphenylporphyrin cobalt complex, phthalocyanine iron complex, phthalocyanine copper complex, phthalocyanine lead complex, organic molecules such as phthalocyanine silicon complex, and Similar results were obtained when inorganic molecules such as zinc oxide were used as NO 2 selective adsorption molecules. Although nitrogen dioxide has been described as an example of the NOx component, the same effect can be obtained for nitric oxide and other nitrogen oxides.
【００４０】また、選択吸着分子薄膜の形成法として真
空蒸着法を例に挙げて述べたが、クラスターイオンビー
ム（ＩＣＢ）法、ラングミュアー―ブロジェット（Ｌ
Ｂ）法及びスピンコート法などの薄膜形成法を用いても
同様の効果を結果を示した。The vacuum deposition method has been described as an example of the method of forming the selectively adsorbed molecule thin film, but the cluster ion beam (ICB) method and the Langmuir-Blodgett (L
The same effect was shown by using a thin film forming method such as B) method and spin coating method.
【００４１】また、粒径の制御が可能な化合物薄膜とし
て弗化マグネシウム蒸着膜を例に挙げて述べたが、これ
に限るものではなく他の化合物でも良く、薄膜の粒径は
主に化合物自体の性質で決まるので、所望の粒径、即ち
凹凸が得られるよう適宜選択すれば良い。Although a magnesium fluoride vapor deposition film has been described as an example of a compound thin film whose grain size can be controlled, the compound thin film is not limited to this, and other compounds may be used. Since it is determined by the property, it may be appropriately selected so as to obtain a desired particle size, that is, unevenness.
【００４２】さらに、感応薄膜に形成する凹凸としては
膜の厚さや、大きさ等にもよるが、吸着表面積ができる
だけ大きくなるように細かい方が望ましく、凹凸の大き
さとしては平均ピッチが0.01〜500μｍ程度が適当で、
0.1〜10μｍがより望ましい。Further, the unevenness formed on the sensitive thin film is preferably as small as possible so that the adsorption surface area is as large as possible depending on the thickness and size of the film, and the unevenness has an average pitch of 0.01 to 500 μm is suitable,
0.1-10 μm is more desirable.
【００４３】[0043]
【発明の効果】本発明の窒素酸化物ガスセンサ用感応薄
膜の形成方法においては、窒素酸化物ガスを選択的に吸
着する感応薄膜を成膜するに際し、上記感応薄膜を形成
する基板または下地薄膜に凹凸を形成し、成膜後の上記
感応薄膜の表面部に凹凸が形成されるようにする、もし
くは成膜後の感応薄膜の表面部に直接凹凸を形成するよ
うにしたので、感応薄膜の表面積を大幅に増大でき、吸
着反応面積も大幅に増加させることができるので、ＮＯ
x ガス分子への吸着力と吸着速度が高まり、高感度で高
速応答性のＮＯx センサーが得られる効果がある。According to the method of forming a sensitive thin film for a nitrogen oxide gas sensor of the present invention, when forming a sensitive thin film that selectively adsorbs nitrogen oxide gas, a substrate or a base thin film on which the sensitive thin film is formed is formed. Since the unevenness is formed so that the unevenness is formed on the surface portion of the above-mentioned sensitive thin film after film formation, or the unevenness is formed directly on the surface portion of the sensitive thin film after film formation, the surface area of the sensitive thin film is Can be significantly increased, and the adsorption reaction area can also be greatly increased.
This has the effect of increasing the adsorption power and adsorption speed to x gas molecules and providing a highly sensitive and fast-responsive NOx sensor.
【００４４】パターニングにより凹凸を形成する。Concavities and convexities are formed by patterning.
【００４５】また、例えば弗化マグネシウム蒸着膜のよ
うに、下地薄膜を粒径の制御が可能な化合物で形成する
ことにより、感応薄膜に容易に任意のサイズの凹凸を形
成、任意の面粗度に粗面化できる効果がある。Further, by forming the underlying thin film with a compound whose grain size can be controlled, such as a magnesium fluoride vapor deposition film, irregularities of any size can be easily formed on the sensitive thin film, and any surface roughness can be obtained. There is an effect that can be roughened.
【００４６】さらに、感応薄膜成膜時に基板の温度を室
温以下の低温にすることにより分子の充填密度が減少す
ることから、ガス分子の薄膜内部への拡散が速やかとな
り吸着速度が大きくなるので、さらに、感度、応答性及
び検出濃度範囲を向上できる効果がある。Furthermore, since the packing density of molecules is reduced by lowering the temperature of the substrate below room temperature during deposition of the sensitive thin film, the diffusion of gas molecules into the thin film is accelerated and the adsorption rate is increased. Further, there is an effect that the sensitivity, responsiveness and detection concentration range can be improved.
【図１】本発明の一実施例の感応薄膜の形成方法を工程
順に示す断面模式図である。FIG. 1 is a schematic sectional view showing a method of forming a sensitive thin film according to an embodiment of the present invention in the order of steps.
【図２】本発明の一実施態様の差動方式を用いたＮＯx
ガスセンサシステムの構成図である。FIG. 2 is an NOx using a differential system according to an embodiment of the present invention.
It is a block diagram of a gas sensor system.
【図３】本発明の一実施例及び比較例の二酸化窒素の吸
着特性を水晶振動子の周波数差の変化で示す特性図であ
る。FIG. 3 is a characteristic diagram showing adsorption characteristics of nitrogen dioxide according to one example and a comparative example of the present invention by a change in frequency difference of a crystal resonator.
【図４】本発明の他の実施態様の電気伝導方式を用いた
ＮＯx ガスセンサーシステムの構成図である。FIG. 4 is a configuration diagram of a NOx gas sensor system using an electric conduction system according to another embodiment of the present invention.
【図５】本発明の実施例及び比較例の二酸化窒素の吸着
特性を電気伝導特性の変化で示す特性図である。FIG. 5 is a characteristic diagram showing the adsorption characteristics of nitrogen dioxide of Examples and Comparative Examples of the present invention by the change of electric conduction characteristics.
【図６】本発明の他の実施例の感応薄膜の形成方法を工
程順に示す断面模式図である。FIG. 6 is a schematic sectional view showing a method of forming a sensitive thin film according to another embodiment of the present invention in the order of steps.
【図７】本発明のさらに他の実施例の感応薄膜の形成方
法を工程順に示す断面模式図である。FIG. 7 is a schematic sectional view showing a method of forming a sensitive thin film according to still another embodiment of the present invention in the order of steps.
【図８】従来の感応薄膜の形成方法を工程順に示す断面
模式図である。FIG. 8 is a schematic sectional view showing a method of forming a conventional sensitive thin film in the order of steps.
１ 基板 ２ 下地薄膜の弗化マグネシウム蒸着膜 ３ 感応薄膜のテトラフェニルポルフィリンルテニウム
ジピリジン錯体の蒸着膜 ４ 水晶振動子 ６ 発振回路 ７ 周波数カウンター ８ ガス流入装置 １２ 感応薄膜の銅フタロシアニン錯体の蒸着膜 １４ 金電極 １５ 基準抵抗 １８ ガス流入装置 ２１ マスク ２２ 金属アルミニウム蒸着膜 ２３ 水晶基板 ２４ フォトレジスト ２５ フォトマスク ２６ 金蒸着膜 ２７ 電極の銀蒸着膜1 Substrate 2 Magnesium Fluoride Vapor Deposition Film of Underlayer Thin Film 3 Sensitive Thin Film of Tetraphenylporphyrin Ruthenium Dipyridine Complex Vapor Deposition 4 Quartz Resonator 6 Oscillation Circuit 7 Frequency Counter 8 Gas Inflow Device 12 Vapor Deposition Film of Copper Phthalocyanine Complex of Sensitive Thin Film 14 Gold electrode 15 Reference resistance 18 Gas inflow device 21 Mask 22 Metal aluminum vapor deposition film 23 Crystal substrate 24 Photoresist 25 Photomask 26 Gold vapor deposition film 27 Silver vapor deposition film of electrode
───────────────────────────────────────────────────── フロントページの続き (72)発明者 花里 善夫 尼崎市塚口本町８丁目１番１号 三菱電機 株式会社中央研究所内 (72)発明者 太田 尚美 尼崎市塚口本町８丁目１番１号 三菱電機 株式会社中央研究所内 (72)発明者 神谷 俊行 尼崎市塚口本町８丁目１番１号 三菱電機 株式会社中央研究所内 (72)発明者 磯田 悟 尼崎市塚口本町８丁目１番１号 三菱電機 株式会社中央研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshio Hanari, 8-1-1 Tsukaguchi Honcho, Amagasaki City, Central Research Laboratory, Mitsubishi Electric Corporation (72) Inventor Naomi Ota 8-1-1 Tsukaguchi Honmachi, Amagasaki Mitsubishi Central Electric Laboratory Co., Ltd. (72) Inventor Toshiyuki Kamiya 8-1-1 Tsukaguchi Honmachi, Amagasaki City Mitsubishi Electric Corporation Central Laboratory (72) Inventor Satoru Isoda 8-1-1 Tsukaguchi Honmachi, Amagasaki Mitsubishi Electric Corporation Company Central Research Institute
Claims (6)
薄膜を成膜するに際し、上記感応薄膜を形成する基板ま
たは下地薄膜に凹凸を形成し、成膜後の上記感応薄膜の
表面部に凹凸が形成されるようにしたことを特徴とする
窒素酸化物ガスセンサ用感応薄膜の形成方法。1. When forming a sensitive thin film that selectively adsorbs nitrogen oxide gas, unevenness is formed on a substrate or a base thin film on which the sensitive thin film is formed, and the surface of the sensitive thin film is formed on the substrate. A method for forming a sensitive thin film for a nitrogen oxide gas sensor, characterized in that unevenness is formed.
形成して凹凸を形成するようにしたことを特徴とする請
求項第１項記載の窒素酸化物ガスセンサ用感応薄膜の形
成方法。2. The method for forming a sensitive thin film for a nitrogen oxide gas sensor according to claim 1, wherein the underlying thin film is formed of a compound whose grain size can be controlled to form irregularities.
ることを特徴とする請求項第２項記載の窒素酸化物ガス
センサ用感応薄膜の形成方法。3. The method for forming a sensitive thin film for a nitrogen oxide gas sensor according to claim 2, wherein the underlying thin film is a magnesium fluoride vapor deposition film.
薄膜を成膜した後、この感応薄膜の表面部に凹凸を形成
するようにしたことを特徴とする窒素酸化物ガスセンサ
用感応薄膜の形成方法。4. A sensitive thin film for a nitrogen oxide gas sensor, characterized in that after forming a sensitive thin film that selectively adsorbs nitrogen oxide gas, irregularities are formed on the surface of this sensitive thin film. Forming method.
にしたことを特徴とする請求項第１項ないし第４項のい
ずれかに記載の窒素酸化物ガスセンサ用感応薄膜の形成
方法。5. The method for forming a sensitive thin film for a nitrogen oxide gas sensor according to claim 1, wherein the unevenness is formed by patterning.
の低温に保持するようにしたことを特徴とする請求項第
１項ないし第５項のいずれかに記載の窒素酸化物ガスセ
ンサ用感応薄膜の形成方法。6. The sensitive material for a nitrogen oxide gas sensor according to claim 1, wherein the temperature of the substrate is maintained at a low temperature of room temperature or lower during deposition of the sensitive thin film. Method of forming thin film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27964092A JPH06128721A (en) | 1992-10-19 | 1992-10-19 | Formation of sensitive thin film for gaseous nitrogen oxide sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27964092A JPH06128721A (en) | 1992-10-19 | 1992-10-19 | Formation of sensitive thin film for gaseous nitrogen oxide sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06128721A true JPH06128721A (en) | 1994-05-10 |
Family
ID=17613804
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27964092A Pending JPH06128721A (en) | 1992-10-19 | 1992-10-19 | Formation of sensitive thin film for gaseous nitrogen oxide sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06128721A (en) |
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| DE3631130A1 (en) * | 1985-09-18 | 1987-03-26 | Hitachi Ltd | EXHAUST-DRIVEN TWO-CHANNEL TURBOCHARGER |
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