JPH0348644B2 - - Google Patents
Info
- Publication number
- JPH0348644B2 JPH0348644B2 JP58105423A JP10542383A JPH0348644B2 JP H0348644 B2 JPH0348644 B2 JP H0348644B2 JP 58105423 A JP58105423 A JP 58105423A JP 10542383 A JP10542383 A JP 10542383A JP H0348644 B2 JPH0348644 B2 JP H0348644B2
- Authority
- JP
- Japan
- Prior art keywords
- zinc oxide
- humidity
- thin film
- oxide thin
- lead
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 85
- 239000011787 zinc oxide Substances 0.000 claims description 42
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 37
- 239000010409 thin film Substances 0.000 claims description 34
- 229910052759 nickel Inorganic materials 0.000 claims description 19
- 238000004544 sputter deposition Methods 0.000 description 16
- 238000001514 detection method Methods 0.000 description 12
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 10
- 229910052744 lithium Inorganic materials 0.000 description 10
- 239000000758 substrate Substances 0.000 description 10
- 230000004044 response Effects 0.000 description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 230000004043 responsiveness Effects 0.000 description 6
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 239000010408 film Substances 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 229910052725 zinc Inorganic materials 0.000 description 5
- 239000011701 zinc Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 229910017052 cobalt Inorganic materials 0.000 description 3
- 239000010941 cobalt Substances 0.000 description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000005546 reactive sputtering Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 244000126211 Hericium coralloides Species 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 229910000480 nickel oxide Inorganic materials 0.000 description 2
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 2
- 229910052573 porcelain Inorganic materials 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 229910018068 Li 2 O Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- -1 iron and cobalt Chemical class 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Non-Adjustable Resistors (AREA)
Description
【発明の詳細な説明】
この発明は鉛とリツケルを含有した酸化亜鉛薄
膜よりなる湿度センサに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a humidity sensor made of a zinc oxide thin film containing lead and Litkel.
従来から存在する電気抵抗式の湿度センサとし
ては、櫛型電極上に固体電解質を高分子材料と架
橋重合させた有機物皮膜からなる湿度センサ、あ
るいは多孔性金属酸化物磁器を用いた湿度センサ
が知られている。 Conventional electrical resistance humidity sensors include humidity sensors made of an organic film made by cross-linking and polymerizing a solid electrolyte with a polymeric material on a comb-shaped electrode, and humidity sensors using porous metal oxide porcelain. It is being
しかしながら、前者の有機物皮膜からなる湿度
センサは、高温での使用ができないこと、長時間
の結露した環境下では電解質が溶け出すなどの欠
点があつた。 However, the former humidity sensor made of an organic film has drawbacks such as not being able to be used at high temperatures and the electrolyte leaching out in an environment with long-term dew condensation.
また多孔性金属酸化物磁器を用いた湿度センサ
は、初期においてはすぐれた湿度応答を有するも
のであるが、長時間使用すると水分子が空孔の奥
深くに浸入し、化学吸着するようになり表面抵抗
は上昇する。 Humidity sensors using porous metal oxide porcelain have an excellent humidity response in the initial stage, but when used for a long time, water molecules penetrate deep into the pores and become chemically adsorbed on the surface. Resistance increases.
これを再生するために加熱によるクリーニング
が必要となり、ヒータ制御回路という複雑な機構
が必要である。 In order to regenerate this, cleaning by heating is required, and a complicated mechanism called a heater control circuit is required.
一方酸化亜鉛を用いた湿度センサも従来からよ
く知られている。これはセラミツク、ガラスなど
の絶縁基板の上に酸化亜鉛の薄膜を形成し、さら
にこの上に一対の検出電極を形成したものであ
る。 On the other hand, humidity sensors using zinc oxide have also been well known. This consists of forming a thin film of zinc oxide on an insulating substrate such as ceramic or glass, and further forming a pair of detection electrodes on this.
この湿度センサは雰囲気の湿度が変化したとき
抵抗値が変化するという特性を有するものであ
り、応答性が速いという特徴をもつている。 This humidity sensor has a characteristic that its resistance value changes when the humidity of the atmosphere changes, and is characterized by quick response.
ところがこの抵抗値は、実用測定範囲内にある
ことが重要であるが、酸化亜鉛と場合抵抗値をこ
の実用測定範囲内にコントロールするに用いる元
素もあまり知られていない。 However, although it is important that this resistance value be within a practical measurement range, the elements used to control the resistance value within this practical measurement range are not well known when using zinc oxide.
また、この酸化亜鉛薄膜を用いた湿度センサは
主として酸化亜鉛の金属過剰のｎ型半導体であ
る。 Moreover, the humidity sensor using this zinc oxide thin film is mainly an n-type semiconductor with a metal excess of zinc oxide.
そしてこのｎ型半導体をスパツタリング法で形
成するためには、酸素量をへらしてスパツタリン
グする方法が考えられるが、酸素を減らすとある
限界値で急激に亜鉛金属のスパツタ膜が形成され
るようになり、この条件をコントロールすること
が困難であつた。 In order to form this n-type semiconductor by a sputtering method, a method of sputtering with a reduced amount of oxygen can be considered, but when the amount of oxygen is reduced, a sputtered film of zinc metal suddenly forms at a certain limit. However, it was difficult to control this condition.
本発明者らは上記の点から酸化亜鉛薄膜を用い
た湿度センサで実用測定範囲内に抵抗値を有する
ものを得るべく検討を行い、鉛を含有した酸化亜
鉛薄膜よりなる湿度センサであれば、抵抗値が容
易に下り、加熱によるクリーニング処理をするこ
となく湿度の連続測定が可能であることを見出
し、さきに特許出願を行つた。 In view of the above, the present inventors conducted studies to obtain a humidity sensor using a zinc oxide thin film that has a resistance value within the practical measurement range.If the humidity sensor is made of a zinc oxide thin film containing lead, They discovered that the resistance value could be easily reduced and that humidity could be measured continuously without cleaning by heating, and they filed a patent application.
ところが鉛を含有しただけでは抵抗を下げる効
果は有するものの湿度に対する応答性、特に復帰
時間が長いという欠陥のあることがわかつた。 However, it has been found that although lead alone has the effect of lowering the resistance, it has drawbacks in its responsiveness to humidity, particularly in its long recovery time.
そこで、この応答性をさきに改善すべく検討を
続けた結果、鉛とともにリチウムを加えることに
よつて抵抗値を下げる効果を有して、かつ湿度に
対する応答性、特に復帰時間の短縮がはかれるこ
とを見出した。 Therefore, as a result of continuing studies to improve this responsiveness, we found that adding lithium along with lead has the effect of lowering the resistance value, and also shortens the responsiveness to humidity, especially the recovery time. I found out.
ところが鉛とリチウムを含有した酸化亜鉛薄膜
を得ること、特に亜鉛金属中にリチウムを添加す
ることは技術的に非常に困難であり、このため酸
化リチウム（Li2O）を鉛を含有した亜鉛合金上
にのせるなどの方法が行なわれたが、この方法で
は酸化亜鉛薄膜中に同じ量を安定して添加するこ
とは困難である。 However, it is technically very difficult to obtain a zinc oxide thin film containing lead and lithium, especially adding lithium to zinc metal. Methods such as adding the same amount to the zinc oxide thin film have been used, but with this method it is difficult to stably add the same amount into the zinc oxide thin film.
またリチウムをLi2Oの酸化物の形で添加して
焼結した酸化亜鉛焼結体を用いる方法も考えられ
たが、焼結中にリチウムの飛散があり、一定量の
鉛とリチウムを添加した焼結体ターゲツトを得る
のは困難であつた。 Another idea was to use a zinc oxide sintered body in which lithium was added in the form of Li 2 O oxide, but lithium would scatter during sintering, so it was necessary to add a certain amount of lead and lithium. It was difficult to obtain a sintered target with a high temperature.
そこで本発明者らはリチウムに代えて合金化可
能であつてしかもリチウム添加と同等の湿度に対
する応答性や復帰時間の短縮がはかれる湿度セン
サを得るべく種々検討の結果、鉛とともにニツケ
ルを加えるならば上記特性のある湿度センサが得
られることを見出したものである。 Therefore, the present inventors conducted various studies in order to obtain a humidity sensor that can be alloyed in place of lithium, and has the same responsiveness to humidity and shortened recovery time as when adding lithium. It has been discovered that a humidity sensor having the above characteristics can be obtained.
即ち、この発明の湿度センサは、感湿要素が鉛
とニツケルを含有した酸化亜鉛薄膜よりなるもの
であつて、これによつて
(1) 高湿度中に放置しても自己復帰性があり、ク
リーニングを必要としないこと、
(2) 応答性がはやいこと、
(3) 実用測定が容易な範囲の抵抗値を有するこ
と、
(4) 耐久性が良好であること、
(5) 合金ターゲツトとして用いることができるた
め、安価でありまたスパツタリング効率も高
く、コストダウンにも寄与すること、
などの効果を奏するのである。 That is, in the humidity sensor of the present invention, the humidity sensing element is made of a zinc oxide thin film containing lead and nickel, and as a result, (1) it has self-recovery properties even if left in high humidity; Does not require cleaning, (2) has fast response, (3) has a resistance value that is easy to measure in practical use, (4) has good durability, and (5) can be used as an alloy target. Therefore, it is inexpensive, has high sputtering efficiency, and contributes to cost reduction.
以下この発明の湿度センサについて詳細に説明
する。 The humidity sensor of the present invention will be explained in detail below.
第１図はこの発明にかかる湿度センサの一列を
示す概略平面図であつて、１はセラミツク、ガラ
スなどからなる絶縁基板であり、この基板１上に
はくし歯状の一対の検出電極２，３が形成され、
さらにくし歯部分を覆うように感湿要素である酸
化亜鉛薄膜４が形成されている。 FIG. 1 is a schematic plan view showing a row of humidity sensors according to the present invention, in which 1 is an insulating substrate made of ceramic, glass, etc., and a pair of comb-shaped detection electrodes 2, 3 are mounted on this substrate 1. is formed,
Furthermore, a zinc oxide thin film 4, which is a moisture-sensitive element, is formed to cover the comb tooth portion.
５，６は検出電極２，３にそれぞれ接続された
端子である。なお図示省略したが、酸化亜鉛薄膜
４上に多孔性の検出電極を網目状またはくし歯状
に形成したもの、あるいは上下平行電極によるバ
ルク型のものであつてもよく、電極はAu、Ni、
Cr、Ti、Cu、Feなどの導電性物質をマスク蒸着
法などにより形成すればよい。 5 and 6 are terminals connected to the detection electrodes 2 and 3, respectively. Although not shown, it may be a porous detection electrode formed on the zinc oxide thin film 4 in a mesh or comb shape, or a bulk type with upper and lower parallel electrodes, and the electrodes may be made of Au, Ni,
A conductive material such as Cr, Ti, Cu, or Fe may be formed by a mask evaporation method or the like.
酸化亜鉛薄膜４を形成する手段としては、例え
ばスパツタリング法、真空蒸着法、イオンプレー
テイング法などがあるが、特に形成手段の容易さ
から反応性スパツタリング法が適している。 Methods for forming the zinc oxide thin film 4 include, for example, a sputtering method, a vacuum evaporation method, an ion plating method, etc., and a reactive sputtering method is particularly suitable because of its ease of formation.
この発明において、感湿要素である酸化亜鉛薄
膜に含有させる鉛およびニツケルの使用範囲とし
ては、鉛は0.1〜20原子％、好ましくは３〜４原
子％であり、ニツケルは0.1〜20原子％、好まし
くは0.5〜２原子％が望ましい。 In this invention, the usage range of lead and nickel to be contained in the zinc oxide thin film, which is a moisture sensitive element, is 0.1 to 20 atom% for lead, preferably 3 to 4 atom%, and 0.1 to 20 atom% for nickel. Preferably it is 0.5 to 2 atomic %.
この理由は、鉛が0.1原子％以下では抵抗値は
108Ω以上となり、実用測定可能範囲を越え、20
原子％以上を用いると、湿度に対する抵抗変化が
小さくなつて好ましくなく、またニツケルが0.1
原子％以下では添加の効果がなく、20原子％以上
では抵抗値が上昇して鉛との併用効果が得られ
ず、何れも湿度センサとしては不適当である。 The reason for this is that when lead is less than 0.1 atomic%, the resistance value is
10 8 Ω or more, exceeding the practical measurable range, and 20 Ω or more.
If atomic percent or more is used, the resistance change with humidity will be small, which is undesirable, and if nickel is 0.1
Below atomic %, there is no effect of addition, and above 20 atomic %, the resistance value increases and no effect can be obtained when used in combination with lead, and both are inappropriate as a humidity sensor.
ここで、この発明の感湿要素である鉛とニツケ
ルの併用について説明すると、鉛を加えることに
より抵抗値は下がるが応答性、再現性が好ましく
ない。しかしてこの鉛とニツケルの両者を添加す
ると応答性、再現性が改善されるのである。これ
は、鉛にさらにニツケルが添加されると、スパツ
タリングによる酸化亜鉛薄膜の形成過程で、まず
鉛の存在で酸化亜鉛薄膜はｎ型半導体層を形成
し、界面に酸化ニツケル層を析出させながら成長
する。ここで薄膜が形成された状態では、感湿要
素の表面部分に酸化ニツケルがｐ型半導体となつ
て形成され、ｎ型の酸化亜鉛とpn接合を作るこ
とになる。このように感湿要素の表面部分にpn
接合が形成されることによつて、水分が付着した
場合、pn接合部分ですばやく電気抵抗の変化を
もたらして、応答性が改善されるものと考えられ
る。しかも、構造的にpn接合が感湿要素表面に
安定して形成されるため、湿度の変化に対して
も、再現性よく湿度検知が行なえるという効果が
得られると推察される。 Here, the combination of lead and nickel, which is the moisture-sensitive element of the present invention, will be explained. Adding lead lowers the resistance value, but the response and reproducibility are unfavorable. However, adding both lead and nickel to the lever improves response and reproducibility. This is because when nickel is further added to lead, during the process of forming a zinc oxide thin film by sputtering, the zinc oxide thin film first forms an n-type semiconductor layer due to the presence of lead, and then grows while depositing a nickel oxide layer at the interface. do. When the thin film is formed, nickel oxide is formed as a p-type semiconductor on the surface of the moisture-sensitive element, forming a p-n junction with n-type zinc oxide. In this way, pn on the surface part of the moisture sensitive element.
It is thought that due to the formation of a junction, when moisture adheres, the electrical resistance changes quickly at the pn junction, improving responsiveness. Moreover, since the pn junction is structurally stably formed on the surface of the humidity-sensitive element, it is presumed that humidity detection can be performed with good reproducibility even in response to changes in humidity.
しかし、ニツケルの添加で抵抗値は上昇するの
で、鉛とニツケルの添加比はまず実用抵抗値が湿
度40％で1MΩ以下になるように調整することが
必要である。従つて両者の使用量としては、酸化
亜鉛薄膜中に鉛３〜４原子％、ニツケル0.5〜２
原子％程度が最も好ましい。 However, since the resistance value increases with the addition of nickel, it is first necessary to adjust the addition ratio of lead and nickel so that the practical resistance value is 1 MΩ or less at 40% humidity. Therefore, the amount of both used is 3 to 4 atomic percent of lead and 0.5 to 2 atomic percent of nickel in the zinc oxide thin film.
The most preferable amount is about atomic percent.
ニツケルの他に遷移金属として鉄、コバルトが
あるが、次のような理由により湿度センサとして
利用が困難なものである。つまり、鉄、コバルト
はニツケルと異なり、スパツタリングにより酸化
亜鉛薄膜の形成時に表面にｐ型半導体が形成され
ず、感湿要素の表面部分にpn接合が形成されな
いため、応答性、再現性が劣る。したがつて、こ
の発明のような湿度センサとして実用に供するこ
とのできないものである。 In addition to nickel, there are transition metals such as iron and cobalt, but they are difficult to use as humidity sensors for the following reasons. That is, unlike nickel, iron and cobalt do not form a p-type semiconductor on the surface when forming a zinc oxide thin film by sputtering, and a pn junction is not formed on the surface of the moisture-sensitive element, resulting in poor responsiveness and reproducibility. Therefore, it cannot be put to practical use as a humidity sensor like the one of the present invention.
以下この発明を一実施例により詳細に説明す
る。 The present invention will be explained in detail below using one example.
実施例
アルミナ基板上にくし歯の間隔が0.5mm、対向
長さが65mmの金からなるくし歯状の検出電極を形
成した。Example A comb-shaped detection electrode made of gold with a comb-teeth spacing of 0.5 mm and a facing length of 65 mm was formed on an alumina substrate.
さらにこの上にくし歯部分を覆うように、鉛と
ニツケルを含有する酸化亜鉛薄膜をスパツタリン
グ法により形成した。 Furthermore, a zinc oxide thin film containing lead and nickel was formed by sputtering to cover the comb tooth portions.
この酸化亜鉛薄膜の形成は、ターゲツトとして
金属亜鉛を用いて次のようにして行なつた。 This zinc oxide thin film was formed using metallic zinc as a target in the following manner.
くし歯状の検出電極を形成したアルミナ基板を
スパツタリング装置の陽極側に設置した。一方陰
極側にはあらかじめ金属亜鉛に鉛３原子％とニツ
ケル１原子％を混入し、溶融して得た合金をター
ゲツトとして配置した。 An alumina substrate on which a comb-shaped detection electrode was formed was placed on the anode side of the sputtering device. On the other hand, on the cathode side, an alloy obtained by mixing metal zinc with 3 at. % of lead and 1 at. % of nickel and melting the mixture was placed as a target.
そしてスパツタリング室内の真空圧を５×
10-7Torrとし、酸素（O2）とアルゴン（Ar）の
比率１：１からなる混合ガスをスパツタリング室
内に導入し、該室内を３×10-4Torrの圧力に保
つた。 Then, the vacuum pressure in the sputtering chamber was increased to 5×
A mixed gas consisting of oxygen (O 2 ) and argon (Ar) in a ratio of 1:1 was introduced into the sputtering chamber, and the pressure in the chamber was maintained at 3 ×10 −4 Torr.
その後排気弁を調整し、スパツタリング室圧力
が1.5×10-1Torrになるように調整し、300Wの高
周波電源（13.56MHz）を供給してくし歯状の検
出電極を有するアルミナ基板上に鉛とニツケルを
含有する膜厚1μｍの酸化亜鉛薄膜を形成した。 After that, the exhaust valve was adjusted so that the sputtering chamber pressure was 1.5 × 10 -1 Torr, and a 300W high-frequency power source (13.56MHz) was supplied to conduct a lead test on an alumina substrate with a comb-like detection electrode. A 1 μm thick zinc oxide thin film containing nickel was formed.
なお上記実施例ではターゲツトとして金属亜鉛
を用い、反応性スパツタリング法により酸化亜鉛
薄膜を形成する例を示したが、ターゲツトとして
酸化亜鉛の焼結体を用いることも可能である。そ
してこの場合の酸化亜鉛焼結体は、例えば酸化亜
鉛粉末を主体とし、これに鉛に換算して３原子％
のPb3O4とニツケルに換算して１原子％のNiOを
添加し、十分粉砕混合したものを500〜600℃で仮
焼し、その後プレスにてデイスク状に成形したも
のを700〜1300℃で焼結することによつて得るこ
とができる。 In the above embodiment, metal zinc was used as the target and a zinc oxide thin film was formed by the reactive sputtering method, but it is also possible to use a sintered body of zinc oxide as the target. The zinc oxide sintered body in this case is, for example, mainly composed of zinc oxide powder, and contains 3 at.% in terms of lead.
of Pb 3 O 4 and 1 atomic % NiO (calculated as nickel) are added, thoroughly ground and mixed, calcined at 500 to 600℃, then pressed into a disc shape and heated to 700 to 1300℃. It can be obtained by sintering with
またこの酸化亜鉛焼結体をターゲツトとする場
合の反応性スパツタリングにおけるスパツタリン
グ室内にはAr：O2＝９：１の混合ガスを用いる
ことが好ましい。 Further, it is preferable to use a mixed gas of Ar:O 2 =9:1 in the sputtering chamber in reactive sputtering when this zinc oxide sintered body is targeted.
上記実施例においては、アルミナ等の絶縁基板
上に一対のくし歯状の検出電極を形成し、その上
にスパツタリング法で酸化亜鉛薄膜を形成したも
のを示したが、この発明の湿度センサはこのよう
な構造に限定されるものではなく、このほかにア
ルミナ等の絶縁基板上にスパツタリング法で酸化
亜鉛薄膜を形成し、その上に一対のくし歯状の検
出電極を形成した構造、あるいは導電性基板例え
ばステンレス、アルミニウム板等の上にスパツタ
リング法で酸化亜鉛薄膜を形成し、その上にくし
歯状検出電極もしくは金の島状蒸着膜あるいは多
孔性銀ペーストによる電極を形成し、上下電極間
の抵抗値を測定する構造のもの、などであつても
よい。 In the above embodiment, a pair of comb-shaped detection electrodes were formed on an insulating substrate such as alumina, and a zinc oxide thin film was formed thereon by sputtering. In addition, the structure is not limited to this structure, but there is also a structure in which a zinc oxide thin film is formed by sputtering on an insulating substrate such as alumina, and a pair of comb-like detection electrodes are formed on it, or a conductive structure. A zinc oxide thin film is formed by sputtering on a substrate such as a stainless steel or aluminum plate, and a comb-like detection electrode, an island-like vapor-deposited film of gold, or a porous silver paste electrode is formed on top of the zinc oxide thin film, and the gap between the upper and lower electrodes is It may also be of a structure for measuring resistance values.
かくして得たスパツタリング法に基づく酸化亜
鉛薄膜は、その形成時には表面に欠陥構造を多く
含み、ガスなどが吸着しやすいため、150℃、24
時間のアニールを行つた。このアニールにより該
酸化亜鉛薄膜の抵抗値は膜形成時より幾分高くな
るが、抵抗値の経時変化が小さくなるのである。 The thus obtained zinc oxide thin film based on the sputtering method contains many defective structures on the surface when it is formed, and gases etc. are easily adsorbed.
Time annealing was performed. This annealing makes the resistance value of the zinc oxide thin film somewhat higher than when the film was formed, but the change in resistance value over time becomes small.
なお、この発明の湿度センサは低温では湿度セ
ンサとして作用するが、300〜500℃の高温にする
とガスセンサとして働き、従つてガス濃度を測定
するときは感応素子を加熱し、相対湿度を測定す
るときは室温にする使い方も可能である。 The humidity sensor of the present invention functions as a humidity sensor at low temperatures, but functions as a gas sensor at high temperatures of 300 to 500 degrees Celsius. Therefore, when measuring gas concentration, the sensing element is heated, and when measuring relative humidity, it is heated. It is also possible to use it at room temperature.
上記実施例で得られたこの発明の湿度センサに
ついてその応答特性を第２図に示すように相対湿
度０％真空中から相対湿度55％の大気中へ取り出
したとき、および相対湿度93％のKNO3飽和塩溶
液から相対湿度55％の大気中へ取り出した時の相
対湿度一電気抵抗曲線から換算した相対湿度指示
値（％）の変化について表わしたところ、この発
明の湿度センサＡは、鉛のみを添加した酸化亜鉛
薄膜を感湿要素とする湿度センサＢおよび鉛とリ
チウムを含有した酸化亜鉛薄膜を感湿要素とする
湿度センサＣにに比べて応答性のはやいことが認
められた。 The response characteristics of the humidity sensor of the present invention obtained in the above example are shown in FIG. 3 Expressing the change in the relative humidity indication value (%) converted from the relative humidity-electrical resistance curve when taken out from a saturated salt solution into the atmosphere with a relative humidity of 55%, it was found that the humidity sensor A of this invention has only lead. It was observed that the response was faster than that of humidity sensor B, which uses a zinc oxide thin film containing lead and lithium as a humidity sensing element, and humidity sensor C, which uses a zinc oxide thin film containing lead and lithium as a humidity sensing element.
またこの発明の湿度センサの自己復帰性を相対
湿度に対する電気抵抗変化にて測定したところ第
３図の結果が得られ、再現性の良いことが認めら
れた。 Furthermore, when the self-resetting property of the humidity sensor of the present invention was measured by the change in electrical resistance with respect to relative humidity, the results shown in FIG. 3 were obtained, and it was recognized that the reproducibility was good.
なお、同図中の実線はこの発明の湿度センサＡ
のもの、破線は比較例の湿度センサＢのものであ
る。また、ニツケルの代りに、鉄、コバルトを鉛
とともに酸化亜鉛の中に含有させた場合、感湿要
素として重要なpn接合が得られないため、低湿
度において抵抗値が低くなり、その結果、低湿度
と高湿度におけるそれぞれの抵抗値を比較した場
合、その抵抗値の変化幅が小さくなり、湿度セン
サとして実用に供することのできないものであ
る。 Note that the solid line in the figure represents the humidity sensor A of the present invention.
The broken line is that of humidity sensor B of the comparative example. Furthermore, if iron or cobalt is contained in zinc oxide along with lead instead of nickel, the pn junction, which is important as a moisture-sensitive element, cannot be obtained, resulting in a low resistance value at low humidity. When comparing the respective resistance values under humidity and high humidity, the range of change in the resistance value becomes small, making it impossible to put it to practical use as a humidity sensor.
第１図はこの発明にかかる湿度センサの一例を
示す概略平面図、第２図は応答特性を示すグラ
フ、第３図は相対湿度一電気抵抗特性図である。
１……絶縁基板、２，３……検出電極、４……
酸化亜鉛薄膜。
FIG. 1 is a schematic plan view showing an example of a humidity sensor according to the present invention, FIG. 2 is a graph showing response characteristics, and FIG. 3 is a relative humidity-electrical resistance characteristic diagram. 1... Insulating substrate, 2, 3... Detection electrode, 4...
Zinc oxide thin film.
Claims (1)
薄膜よりなることを特徴とする湿度センサ。 ２ 酸化亜鉛薄膜に含有する鉛の量が0.1〜20原
子％であることを特徴とする特許請求の範囲第１
項記載の湿度センサ。 ３ 酸化亜鉛薄膜に含有するニツケルの量が0.1
〜20原子％であることを特徴とする特許請求の範
囲第１項記載の湿度センサ。[Scope of Claims] 1. A humidity sensor characterized in that the humidity sensing element is made of a zinc oxide thin film containing lead and Litkel. 2. Claim 1, characterized in that the amount of lead contained in the zinc oxide thin film is 0.1 to 20 atomic %.
Humidity sensor as described in section. 3 The amount of nickel contained in the zinc oxide thin film is 0.1
The humidity sensor according to claim 1, wherein the humidity is 20 atomic %.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58105423A JPS59231802A (en) | 1983-06-13 | 1983-06-13 | Moisture sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58105423A JPS59231802A (en) | 1983-06-13 | 1983-06-13 | Moisture sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59231802A JPS59231802A (en) | 1984-12-26 |
| JPH0348644B2 true JPH0348644B2 (en) | 1991-07-25 |
Family
ID=14407185
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58105423A Granted JPS59231802A (en) | 1983-06-13 | 1983-06-13 | Moisture sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59231802A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9947460B2 (en) | 2013-08-22 | 2018-04-17 | Murata Manufacturing Co., Ltd. | Oxide ceramic and ceramic electronic component |
-
1983
- 1983-06-13 JP JP58105423A patent/JPS59231802A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9947460B2 (en) | 2013-08-22 | 2018-04-17 | Murata Manufacturing Co., Ltd. | Oxide ceramic and ceramic electronic component |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59231802A (en) | 1984-12-26 |
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