JPH0778486B2 - Gas sensor - Google Patents
Gas sensorInfo
- Publication number
- JPH0778486B2 JPH0778486B2 JP62303022A JP30302287A JPH0778486B2 JP H0778486 B2 JPH0778486 B2 JP H0778486B2 JP 62303022 A JP62303022 A JP 62303022A JP 30302287 A JP30302287 A JP 30302287A JP H0778486 B2 JPH0778486 B2 JP H0778486B2
- Authority
- JP
- Japan
- Prior art keywords
- isfet
- gas
- gas sensor
- working electrode
- isfets
- 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 - Fee Related
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【発明の詳細な説明】 本発明はガスセンサに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas sensor.
溶存ガスセンサはポテンシオメトリーにおいて、PH＝一
定の緩衛液のもとでISFETをインピーダンス変換器とし
て、ISFETのゲート膜発生電位を一定となる条件のもと
で作用電極が外部からの溶存ガスによる化学反応により
電位変化を生ずるのをソースフォロアー回路にて読み取
るようにしたもので、実際のセンサ部の構成は、ガス分
子を透過する膜でフロー液と隔てた空間を緩衛液で満た
し、作用電極とISFETチップを配置した構造である。し
かし乍らこのような単一のISFETによる測定回路構成はI
SFETの特性変動の影響を受けるので種々の対策を必要と
するという欠点があった。また参照電極は固体型ではな
く内部液型でICプロセスによって製造されるISFETとな
じまないものであった。In potentiometry, the dissolved gas sensor uses the ISFET as an impedance converter under PH = constant slower solution, and the working electrode depends on the dissolved gas from the outside under the condition that the ISFET gate film generation potential is constant. The source follower circuit reads the potential change caused by a chemical reaction, and the actual sensor configuration is such that the space separated from the flow liquid by a membrane that allows gas molecules to pass through is filled with slow-moving liquid. This is a structure in which electrodes and ISFET chips are arranged. However, the measurement circuit configuration with such a single ISFET is
There is a drawback that various measures are required because it is affected by the characteristic fluctuation of SFET. The reference electrode was not a solid type but an internal liquid type, which was not compatible with ISFET manufactured by the IC process.
本発明は上記の欠点であるISFETの特性変動の影響とい
う問題と全固定化という問題を解決しようとするもので
あり、溶存ガスセンサの構成を簡単にし、センサの信頼
性を向上させるもので、ポテンシオメトリーによる溶存
ガスセンサを実現しようとするものである。The present invention is intended to solve the problem of the influence of the characteristic fluctuation of ISFET and the problem of total immobilization, which are the above-mentioned drawbacks, and to simplify the structure of a dissolved gas sensor and improve the reliability of the sensor. It is intended to realize a dissolved gas sensor by ometry.
第１図は本発明の一実施例回路構成図である。ペアのIS
FET1,2のゲート絶縁膜上にポテンシオメトリー用の作用
電極１´,2´を披着させMIS（Metal−Insulater−Silic
on）構造のFETとして、その一方のISFET1の作用電極１
´を導電性のガス分子不透過膜３で被い、他方のISFET
の作用電極２´はそのままで、この二つのISFET1,2のソ
ースＳに定電流源を接続して定電流のソースフォロアの
差動回路を構成する。そして、選択的にガス分子を透過
する隔膜４で隔てられた緩衛液５中に上記の二つのISFE
Tが配置されている。緩衛液５は参照電極６で接地され
ている。参照電極６は白金や金などの固定金属でよい。
このような構成にすることにより第２図のようにISFET1
とISFET2と参照電極用金属６と作用電極１´,2´をワン
チップ上に制作可能となる。以上のような構成でガス透
過隔膜４を通してガス分子が緩衛液５に解け込むとISFE
T1は、ゲート電極上にガス分子不透過膜３があるので溶
存ガスに不感応である。一方ISFET2は、溶存ガスに感応
する作用電極２´があるので感応し、差動回路によりIS
FETの影響を受けることなく、溶存ガスに応じた出力を
取り出せる。第３図は本発明の他の実施例を示すフロー
型セル構成例で前記第２図に示したワンチップ化された
センサ1,2´をガス透過膜４で隔てられた空間に配置
し、ガス透過膜４とセンサチップ７のわずかなすきまに
緩衛液又はゲル８を満たし、フローする溶液９中の溶存
ガスを検知する構造のものである。FIG. 1 is a circuit configuration diagram of an embodiment of the present invention. IS of a pair
MIS (Metal-Insulater-Silic) is formed by putting working electrodes 1'and 2'for potentiometry on the gate insulating film of FET1 and FET2.
on) structure FET, one of the ISFET1 working electrode 1
′ Is covered with a conductive gas molecule impermeable membrane 3 and the other ISFET
A constant current source is connected to the sources S of the two ISFETs 1 and 2 while leaving the working electrode 2'of the above, and a differential circuit of a constant current source follower is configured. Then, the above two ISFEs are placed in the slow protective liquid 5 separated by the diaphragm 4 that selectively permeates gas molecules.
T is placed. The slow guard liquid 5 is grounded by the reference electrode 6. The reference electrode 6 may be a fixed metal such as platinum or gold.
With such a structure, as shown in Fig. 2, ISFET1
The ISFET2, the reference electrode metal 6, and the working electrodes 1'and 2'can be manufactured on one chip. When gas molecules dissolve through the gas permeable diaphragm 4 into the slow protective liquid 5 with the above structure, ISFE
T1 is insensitive to dissolved gas because the gas molecule impermeable film 3 is on the gate electrode. On the other hand, ISFET2 is sensitive because it has a working electrode 2'which is sensitive to dissolved gas.
The output according to the dissolved gas can be taken out without being affected by the FET. FIG. 3 is a flow-type cell configuration example showing another embodiment of the present invention, in which the one-chip sensors 1 and 2 ′ shown in FIG. The structure has a structure in which a slight clearance between the gas permeable film 4 and the sensor chip 7 is filled with a gentle protective liquid or gel 8 and the dissolved gas in the flowing solution 9 is detected.
又、カテーテル化型センサについてもフロー型と同様な
構成で実現できることは明らかである。Also, it is clear that the catheterized sensor can be realized with the same structure as the flow sensor.
上記の本発明により、溶存ガスセンサの構造が小形化
し、検出の信頼性も向上するのでその効果大である。ま
た、センサチップはIC技術により安価に生産可能なので
安価な溶存ガスセンサを提供できる。According to the present invention described above, the structure of the dissolved gas sensor is downsized, and the reliability of detection is improved, which is a great effect. In addition, since the sensor chip can be manufactured at low cost by IC technology, an inexpensive dissolved gas sensor can be provided.
第１図、第２図、第３図は本発明の実施例の示す構造図
である。図において、1,2はISFET、１´,2´は作用電
極、３はガス分子不透過膜（電極）４はガス分子透過
膜、5,8は緩衛液、６は参照電極、７はチップ、９はフ
ロー溶液である。1, 2 and 3 are structural views showing an embodiment of the present invention. In the figure, 1 and 2 are ISFETs, 1 ′ and 2 ′ are working electrodes, 3 is a gas molecule impermeable film (electrode) 4, is a gas molecule permeable film, 5 and 8 are gentle liquids, 6 is a reference electrode, and 7 is Chip 9 is a flow solution.
Claims (2)
膜上に作用電極を設けてMIS（Metel−Insulater−Silic
on）構造となす二つのISFETの一方のISFETの作用電極を
そのままにし他方のISFETのゲート絶縁膜上の作用電極
を導電性のガス分子不透過膜で被服し、この二つのISFE
Tをガス分子を選択的に透過する膜で隔てられた緩衝液
又はゲル中に配置し、且つ該二つのISFETを定電流ソー
スフォロアにて作動回路構成し差動出力を取り出すこと
を特徴とするガスセンサ。1. A MIS (Metel-Insulater-Silic) is provided by providing a working electrode on each gate insulating film of an ISFET having the same characteristics.
on) structure, the working electrode of one ISFET of the two ISFETs is left as it is, and the working electrode on the gate insulating film of the other ISFET is covered with a conductive gas molecule impermeable film.
T is placed in a buffer or gel separated by a membrane that selectively permeates gas molecules, and the two ISFETs are configured as an operating circuit with a constant current source follower to take out differential outputs. Gas sensor.
pH＝一定の緩衝液で満たした微小空間に上記二つのISFE
Tと固体型参照電極を配置したことを特徴とする特許請
求の範囲第（１）項記載のガスセンサ。2. Separated by a membrane that selectively permeates gas molecules
The above two ISFEs are placed in a micro space filled with a constant pH buffer solution.
The gas sensor according to claim (1), wherein T and a solid type reference electrode are arranged.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62303022A JPH0778486B2 (en) | 1987-11-30 | 1987-11-30 | Gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62303022A JPH0778486B2 (en) | 1987-11-30 | 1987-11-30 | Gas sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01143952A JPH01143952A (en) | 1989-06-06 |
| JPH0778486B2 true JPH0778486B2 (en) | 1995-08-23 |
Family
ID=17915992
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62303022A Expired - Fee Related JPH0778486B2 (en) | 1987-11-30 | 1987-11-30 | Gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0778486B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109115849A (en) * | 2018-08-22 | 2019-01-01 | 广州瑞普医疗科技有限公司 | electrochemical sensor circuit |
-
1987
- 1987-11-30 JP JP62303022A patent/JPH0778486B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01143952A (en) | 1989-06-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |