JPS61181951A - Ion concentration measuring apparatus - Google Patents
Ion concentration measuring apparatusInfo
- Publication number
- JPS61181951A JPS61181951A JP60021747A JP2174785A JPS61181951A JP S61181951 A JPS61181951 A JP S61181951A JP 60021747 A JP60021747 A JP 60021747A JP 2174785 A JP2174785 A JP 2174785A JP S61181951 A JPS61181951 A JP S61181951A
- Authority
- JP
- Japan
- Prior art keywords
- gate electrode
- gate
- amplitude
- measuring device
- phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/403—Cells and electrode assemblies
- G01N27/414—Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は電界効果トランジスタ型イオンセンサ（以下ｌ
５ＦＥＴと記す）を利用するイオン濃度測定装置に関す
るものである。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a field effect transistor type ion sensor (hereinafter referred to as l).
5FET).
ｌ５ＦＥＴを利用するイオン濃度測定装置を用いて被検
液中の電解質濃度を連続的に測定する場合、被検液中吸
着成分のｌ５ＦＥＴゲート感応膜への吸着やｌ５ＦＥＴ
ゲ一ト感応膜自体の変質による感度変化等の要因により
測定誤差を生じる。When continuously measuring the electrolyte concentration in a test solution using an ion concentration measuring device that uses a 15FET, the adsorption of adsorbed components in the test solution to the 15FET gate sensitive membrane and the 15FET
Measurement errors occur due to factors such as changes in sensitivity due to deterioration of the gate sensitive film itself.
このため、定期的にＩ ５ＦＥＴゲート感応膜表面を洗
浄したり、電気計測回路の増幅感度を調節するなどの保
守作業が必要である。Therefore, maintenance work such as periodically cleaning the surface of the I5FET gate sensitive film and adjusting the amplification sensitivity of the electrical measurement circuit is required.
しかしながら、特異な性状の被検液を測定する場合や、
突発的にｌ５ＦＥＴが劣化したような場合には、このよ
うな定期的な保守作業は無力であり、測定誤差が補償さ
れないまま見すごされる危 ・陰性がある。このため、
ｌ５ＦＥＴの状態を連続的にモニターすることが重要な
課題となっており、簡便なモニター法が要望されている
。However, when measuring a test liquid with unique properties,
If the 15FET suddenly deteriorates, such periodic maintenance work is useless, and there is a danger that measurement errors may be ignored without being compensated for. For this reason,
Continuously monitoring the state of the 15FET has become an important issue, and a simple monitoring method is desired.
なお、この種のｌ５ＦＥＴのモニター法は現在まで知ら
れていないが、関連するものには例えば日本国特許公開
公報昭５８−９２８５４がある。Although this type of monitoring method for 15FET is not known to date, related methods include, for example, Japanese Patent Publication No. 1987-92854.
本発明はｌ５ＦＥＴの状態モニターが簡便に行えるイオ
ン濃度測定装置を提供することにある。An object of the present invention is to provide an ion concentration measuring device that can easily monitor the condition of the 15FET.
上記目的を達成するために本発明によるイオン濃度測定
装置は、ｌ５ＦＥＴのゲート絶縁膜中に導電性ゲート電
極を設け、該ゲート電極と基準参照電極との間に交流基
準電流を印加する交流電源及び該ゲート電極と該基準参
照電極間に発生する交流電圧の振幅と位相を測定する検
出回路を具備し、該ゲート電極と被検液間の複素インピ
ーダンスをＪｌす定するよう構成することにより、Ｉ
Ｓ ＦＥＴの状態モニターが簡便に行えるようにしたも
のである。すなわち、ゲート電極被検液間の複素インピ
ーダンス抵抗値によりｌ５ＦＥＴゲー１−絶縁膜の絶縁
状態及びゲートイオン感応膜の含水状態を知ることが可
能であり、また同複素インピーダンス容量値によりｌ５
ＦＥＴゲート感応膜上の吸着成分量を知ることが可能で
あるため容易にｌ５ＦＥＴの状態をモニターすることが
可能となる。In order to achieve the above object, the ion concentration measuring device according to the present invention includes an AC power supply that provides a conductive gate electrode in the gate insulating film of the 15FET, and applies an AC reference current between the gate electrode and the reference reference electrode. The I
This allows easy monitoring of the S FET condition. That is, it is possible to know the insulation state of the l5FET gate insulating film and the water content state of the gate ion-sensitive film from the complex impedance resistance value between the gate electrode test liquid, and from the complex impedance capacitance value, the l5
Since it is possible to know the amount of adsorbed components on the FET gate sensitive film, it is possible to easily monitor the state of the 15FET.
つぎに本発明の実施例を図面とともに説明する。 Next, embodiments of the present invention will be described with reference to the drawings.
第１図は本発明によるゲート絶縁膜中に導電性ゲート電
極の設けられたｌ５ＦＥＴの一実施例の断面図である。FIG. 1 is a cross-sectional view of an embodiment of an 15FET in which a conductive gate electrode is provided in a gate insulating film according to the present invention.
”以下簡単に工程を記す。まずｐ型Ｓｉウェハ１を用い
て、不純物拡散法により（イオン注入法でも良い）ｎ型
ソース２．ドレイン３を形成した。次に熱酸化法により
ＳｉＯ膜を１０００人成長させた後、ＣＶＤ法により３
５００人の導電性ポリシリコンゲート５を形成した。さ
らにＣＶＤ法により５００人のＳｉＯ膜を形成し最終的
に１０００人厚のＳｉＯ膜４とした。次に低圧ＣＶＤ法
により１０００人のＳｉ Ｎ 膜６を形成し、ホト
リソグラフ法によりソース電極７．ドレイン電極８．そ
してゲート電極（第１図中には記載されていない）を形
成した。本実施例では導電性ゲート電極材料にポリシリ
コンを使用したが、この他にＭｏ、Ｗなどのシリサイド
を用いても何んら支障はない。"The steps are briefly described below. First, using a p-type Si wafer 1, an n-type source 2 and drain 3 were formed by an impurity diffusion method (or an ion implantation method). Next, a SiO film with a thickness of 1000 nm was formed by a thermal oxidation method. After growing humans, 3
500 conductive polysilicon gates 5 were formed. Further, a 500-layer SiO film was formed by the CVD method, and the final SiO film 4 was 1000-layer thick. Next, a 1,000-layer Si N film 6 is formed by low-pressure CVD, and a source electrode 7 is formed by photolithography. Drain electrode8. Then, a gate electrode (not shown in FIG. 1) was formed. Although polysilicon is used as the conductive gate electrode material in this embodiment, other silicides such as Mo and W may also be used without any problem.
第２図は第１図の構成によるｌ５ＦＥＴを用いた本発明
によるイオン濃度測定装置の一実施例を示す図である。FIG. 2 is a diagram showing an embodiment of the ion concentration measuring device according to the present invention using the 15FET having the configuration shown in FIG.
ｌ５ＦＥＴ２０と基準参照電極２３を被検液２２中に浸
漬している。基準参照型Ｖｉ２３とｌ５ＦＥＴ２０のソ
ース、ドレイン各配線は濃度計測回路２５に接続され、
被検液２２のイオン濃度が表示器２６により表示される
。本実施例ではｌ５ＦＥＴ２０がｐＨ感応性Ｓｉ Ｎ
をイオン感応膜としているためｐＨ値が表示器２６によ
り表示される。さて、ｌ５ＦＥＴ２０のゲート電極２４
は基準参照電極２３とともに交流電流源２７及び振幅位
相測定器２８に接続されている。振幅位相測定器２８の
位相は交流電源２７の位相を基準としている。交流電流
源２７により印加された交流電流の振幅と振幅位相測定
器２８により測定された交流電圧の振幅及び位相よりｌ
５ＦＥＴ２０のゲート電極２４と被検液２２間の複素イ
ンピーダンス値Ｒ−ｊＸがベクトル割算器２９により計
算２表示される。ｌ５ＦＥＴ２０のゲート絶縁膜の絶縁
状態及びゲートイオン感応膜の含水状態を知る場合には
複素インピーダンスの抵抗成分Ｒを読み、またゲート感
応膜上の吸着成分量を知る場合には複素インピーダンス
の容量成分Ｘを読む構成となっている。The 15FET 20 and the standard reference electrode 23 are immersed in the test liquid 22. The source and drain wirings of the standard reference type Vi23 and 15FET20 are connected to the concentration measurement circuit 25,
The ion concentration of the test liquid 22 is displayed on the display 26. In this example, 15FET20 is made of pH-sensitive SiN
Since the membrane is an ion-sensitive membrane, the pH value is displayed on the display 26. Now, the gate electrode 24 of l5FET20
is connected to an alternating current source 27 and an amplitude phase measuring device 28 together with a reference reference electrode 23 . The phase of the amplitude phase measuring device 28 is based on the phase of the AC power supply 27. From the amplitude of the alternating current applied by the alternating current source 27 and the amplitude and phase of the alternating current voltage measured by the amplitude phase measuring device 28,
A complex impedance value R-jX between the gate electrode 24 of the 5FET 20 and the test liquid 22 is calculated and displayed by the vector divider 29. To know the insulation state of the gate insulating film and the water content state of the gate ion sensitive film of 15FET20, read the resistance component R of the complex impedance, and to find out the amount of adsorbed components on the gate sensitive film, read the capacitance component X of the complex impedance. It is structured to read.
第３図には第２図の構成に従うイオン濃度測定装置を用
いてｌ５ＦＥＴの状態をモニターした結果の一例である
。被検液２２にＰＨ７，０のトリス緩衝溶液を用い、抵
抗成分Ｒの経時変化を調べたものである。経過日数が増
加するに従い抵抗成分Ｒは徐々に減少している。これは
イオン感応膜（本例ではＳｉ Ｎ 膜）が徐々に含
水してゆき、抵抗値が減少したことを表わしている。ま
た３２日目に突然抵抗成分は零となり、Ｓｉ Ｎ
。FIG. 3 shows an example of the results of monitoring the state of the 15FET using the ion concentration measuring device having the configuration shown in FIG. A Tris buffer solution with a pH of 7.0 was used as the test liquid 22, and the change in resistance component R over time was investigated. As the number of days elapsed increases, the resistance component R gradually decreased. This indicates that the ion-sensitive membrane (Si N membrane in this example) gradually became hydrated and the resistance value decreased. Also, on the 32nd day, the resistance component suddenly became zero, and the SiN
.
ＳｉＯ各ゲート絶縁膜が絶縁破壊を起こしたことがわか
る。It can be seen that dielectric breakdown occurred in each SiO gate insulating film.
第４図には第２図の構成に従うイオン濃度測定装置を用
いて、被検液に血清を使用した場合のｌ５ＦＥＴの状態
をモニターした結果の一例である。本実験では血清中成
分のｌ５ＦＥＴゲートイオン感応膜への吸着をモニター
するために容量成分値Ｘを調べた。血清検体処理数が増
加するに従い、容量成分値Ｘは単純に増加し、Ｉ ５Ｆ
ＥＴゲ−ト感応膜上の吸若量が増加していることを示し
ている。第３図及び第４図の結果より、抵抗成分Ｒ２容
量成分Ｘにそれぞれ閾値Ｒ、Ｘ を前もって設定し、
ＲがＲを下回った場合にはＩＳ’ＦＥＴの交換を促す表
示を行う手段、及びＸがＸ を上回った場合にはｌ５Ｆ
ＥＴの洗浄を行う手段を設ければ、イオン濃度測定装置
の保守点検が著しく簡便化されることが明らかである。FIG. 4 shows an example of the results of monitoring the state of the 15FET when serum is used as the test liquid using the ion concentration measuring device having the configuration shown in FIG. In this experiment, the capacitance component value X was examined in order to monitor the adsorption of serum components to the 15FET gate ion-sensitive membrane. As the number of serum samples processed increases, the volume component value X simply increases, and I 5F
This shows that the amount of absorption on the ET gate sensitive membrane is increasing. Based on the results shown in FIGS. 3 and 4, threshold values R and X are set in advance for the resistance component R and the capacitance component X, respectively.
Means for displaying a message prompting the replacement of IS'FET when R is less than R, and l5F when X exceeds X.
It is clear that if a means for cleaning the ET is provided, maintenance and inspection of the ion concentration measuring device will be significantly simplified.
以上の実施例では交流電流源２７を用い、発生交流電圧
の振幅と位相を振幅位相測定器２８で測定したが、交流
電流源２７に代わり電圧源を用い。In the above embodiments, the alternating current source 27 was used and the amplitude and phase of the generated alternating current voltage were measured by the amplitude and phase measuring device 28, but a voltage source was used instead of the alternating current source 27.
発生交流電流の振幅と位相を振幅位相測定器２８で測定
するよう構成しても何んら支障はない。There is no problem in configuring the amplitude and phase measuring device 28 to measure the amplitude and phase of the generated alternating current.
以上より、本発明によるイオン濃度測定装置はＩ Ｓ
ＦＥＴの状態モニターを簡便に行えることが実証された
。From the above, the ion concentration measuring device according to the present invention has IS
It has been demonstrated that the condition of FET can be easily monitored.
上記のように本発明によるイオン濃度測定装置は、被検
液中に浸漬されたｌ５ＦＥＴ及び基準参照電極と、電気
計測回路からなるイオン濃度測定装置において、該ｌ５
ＦＥＴのゲート絶縁膜中に導電性ゲートを設け、該ゲー
ト電極と該基準参照電極との間に交流基＄電流を印加す
る交流電源及び該ゲート電極と該基準参照電極間に発生
する交流電圧の振幅と位相を測定する検出回路を具備し
、該ゲート電極と被検液間の複素インピーダンスを測定
するよう構成したことにより、ｌ５ＦＥＴの状態モニタ
ーが簡便に行える効果がある。As described above, the ion concentration measuring device according to the present invention includes an 15 FET immersed in a test liquid, a standard reference electrode, and an electric measurement circuit.
A conductive gate is provided in the gate insulating film of the FET, and an AC power supply that applies an AC current between the gate electrode and the standard reference electrode, and an AC voltage generated between the gate electrode and the standard reference electrode. By providing a detection circuit for measuring amplitude and phase and configuring to measure the complex impedance between the gate electrode and the test liquid, there is an effect that the state of the 15FET can be easily monitored.
第１図はゲート絶縁膜中に導電性ゲート電極の設けられ
たｌ５ＦＥＴの一実施例の断面図である。
第２図は第１図の構成によるｌ５ＦＥＴを用いた本発明
によルイオン濃度測定装置の一実施例を示す図である。
第３図及び第４図は第１図の構成によるｌ５ＦＥＴ及び
第２図の構成によるイオン濃度測定装置を用いてｌ５Ｆ
ＥＴの状態をモニターした結果を示す図である。
１・・・Ｓｉウェハ、２・・・ソース、３・・・ドレイ
ン。
４・・・ＳｉＯ，５・・・ポリシリコンゲート、６・・
・ＳｉＮ、７・・・ソース電極、８・・・ドレイン電極
、２０・・ｒｓＦＥＴ、２１・・・容器、２２・・被検
液、２３ ・基準参照電極、２４・・ゲート電極、２５
・・濃度計測回路、２６・・表示器、２７・・交流電流
源、２８・・・振幅位相測定器、２９・・・ベクトル割
算器。FIG. 1 is a cross-sectional view of an embodiment of an 15FET in which a conductive gate electrode is provided in a gate insulating film. FIG. 2 is a diagram showing an embodiment of the ion concentration measuring device according to the present invention using the 15FET having the configuration shown in FIG. Figures 3 and 4 show the measurement of the 15F using the 15FET with the configuration shown in Figure 1 and the ion concentration measuring device with the configuration shown in Figure 2.
It is a figure which shows the result of monitoring the state of ET. 1...Si wafer, 2...source, 3...drain. 4...SiO, 5...Polysilicon gate, 6...
- SiN, 7... Source electrode, 8... Drain electrode, 20... rsFET, 21... Container, 22... Test liquid, 23 - Standard reference electrode, 24... Gate electrode, 25
...Concentration measurement circuit, 26..Display device, 27..AC current source, 28..amplitude phase measuring device, 29..vector divider.
Claims (1)
ンサ及び基準参照電極と、電気計測回路からなるイオン
濃度測定装置において、該電界効果トランジスタ型イオ
ンセンサのゲート絶縁膜中に導電性ゲート電極を設け、
該ゲート電極と該基準参照電極との間に交流基準電流を
印加する交流電源及び該ゲート電極と該基準参照電極間
に発生する交流電圧の振幅と位相を測定する検出回路を
具備し該ゲート電極と被検液間の複素インピーダンスを
測定するよう構成したことを特徴とするイオン濃度測定
装置。In an ion concentration measuring device comprising a field effect transistor type ion sensor immersed in a test liquid, a standard reference electrode, and an electric measurement circuit, a conductive gate electrode is provided in the gate insulating film of the field effect transistor type ion sensor. ,
The gate electrode includes an AC power source that applies an AC reference current between the gate electrode and the standard reference electrode, and a detection circuit that measures the amplitude and phase of the AC voltage generated between the gate electrode and the standard reference electrode. An ion concentration measuring device characterized in that it is configured to measure complex impedance between a test liquid and a test liquid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60021747A JPS61181951A (en) | 1985-02-08 | 1985-02-08 | Ion concentration measuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60021747A JPS61181951A (en) | 1985-02-08 | 1985-02-08 | Ion concentration measuring apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61181951A true JPS61181951A (en) | 1986-08-14 |
Family
ID=12063665
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60021747A Pending JPS61181951A (en) | 1985-02-08 | 1985-02-08 | Ion concentration measuring apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61181951A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008134255A (en) * | 2007-12-17 | 2008-06-12 | Hitachi Ltd | Biomolecule detector, and biomolecule detection method using the same |
| JP2010256140A (en) * | 2009-04-23 | 2010-11-11 | National Institute Of Advanced Industrial Science & Technology | Electrochemical measuring device |
| WO2011040803A1 (en) * | 2009-09-29 | 2011-04-07 | Mimos Berhad | A reference electrode and a method thereof |
-
1985
- 1985-02-08 JP JP60021747A patent/JPS61181951A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008134255A (en) * | 2007-12-17 | 2008-06-12 | Hitachi Ltd | Biomolecule detector, and biomolecule detection method using the same |
| JP4731544B2 (en) * | 2007-12-17 | 2011-07-27 | 株式会社日立製作所 | Biomolecule detection apparatus and biomolecule detection method using the same |
| JP2010256140A (en) * | 2009-04-23 | 2010-11-11 | National Institute Of Advanced Industrial Science & Technology | Electrochemical measuring device |
| WO2011040803A1 (en) * | 2009-09-29 | 2011-04-07 | Mimos Berhad | A reference electrode and a method thereof |
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