JPH0684951B2 - Differential type semiconductor chemical sensor - Google Patents
Differential type semiconductor chemical sensorInfo
- Publication number
- JPH0684951B2 JPH0684951B2 JP63023700A JP2370088A JPH0684951B2 JP H0684951 B2 JPH0684951 B2 JP H0684951B2 JP 63023700 A JP63023700 A JP 63023700A JP 2370088 A JP2370088 A JP 2370088A JP H0684951 B2 JPH0684951 B2 JP H0684951B2
- Authority
- JP
- Japan
- Prior art keywords
- isfet
- film
- gate
- sensor
- gate electrode
- 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
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、半導体化学センサに係り、特に溶液中の特定
化学物質濃度を測定するための電界効果トランジスタを
利用した半導体化学センサに関する。Description: TECHNICAL FIELD The present invention relates to a semiconductor chemical sensor, and more particularly to a semiconductor chemical sensor using a field effect transistor for measuring the concentration of a specific chemical substance in a solution.
従来の半導体を用いた化学センサであるイオン選択用電
界効果トランジスタ（ISFET）は、そのゲート構造とし
ては、“センサ・アンド・アクチユエータ，第１巻，
（1981）第77-96頁（Sensor and Actuators,l（1981）7
7-96）”に記載のように、シリコン基板表面にSiO2／Si
3N4を積層した構造が広く用いられている。また、さら
に絶縁ゲート上に導伝性の電極を設けイオン選択性膜を
形成した延長ゲート型（Extended Gate）ISFETが、“セ
ンサ・アンド・アクチユエータ，第４巻（1983）第291-
298頁”に記載されている。A field effect transistor (ISFET) for ion selection, which is a conventional chemical sensor using a semiconductor, has a gate structure such as "Sensor and Actuator, Vol.
(1981) 77-96 (Sensor and Actuators, l (1981) 7
7-96) ”, the surface of the silicon substrate is covered with SiO 2 / Si.
A structure in which 3 N 4 is laminated is widely used. Further, an extended gate type ISFET in which a conductive electrode is provided on an insulated gate and an ion selective film is formed is described in "Sensor and Actuator, Volume 4 (1983) No. 291-
P. 298 ".
上述した従来技術に基づくISFETの出力は比較的大きな
温度特性を持つており、この主な原因は半導体特性にお
けるしきい値電圧やキヤリア移動の温度特性による。こ
れら温度特性の補償については従来配慮されていなかつ
た。The output of the ISFET based on the above-mentioned conventional technique has a relatively large temperature characteristic, and the main cause of this is the temperature characteristic of the threshold voltage and the carrier movement in the semiconductor characteristics. No consideration has been given to the compensation of these temperature characteristics.
本発明は、温度補償の容易な半導体化学センサを提供す
ることを目的としている。An object of the present invention is to provide a semiconductor chemical sensor that can be easily temperature compensated.
上記目的は、半導体パラメータの温度特性が等しい一対
のFETを用い、一つはイオン応答するISFETと、もう１つ
はイオン応答をしないMOSFETとをセンサチツプ基板上に
形成し、各々の出力電圧もしくは電流の差動測定を行う
ことにより達成される。The purpose is to use a pair of FETs having the same temperature characteristics of semiconductor parameters. One is an ISFET that responds to ions, and the other is a MOSFET that does not respond to ions. This is achieved by making a differential measurement of
ISFETのゲート部に、上部表面に酸化層を形成した白金
族金属を、あるいはさらにイオン選択性膜を被覆した電
極を用いることにより基本的にはISFETの構造をMOSFET
とすることができる。一方、同一基板上に形成したMOSF
ETはISFETと同じ金属材料及びゲート絶縁膜からなつて
いるのでISFETと同一の半導体パラメータを有する。こ
のため各々の半導体パラメータの温度特性は同一とな
り、両者の差動をとることにより完全に温度補償するこ
とができる。Basically, the structure of ISFET is MOSFET by using a platinum group metal with an oxide layer formed on the upper surface of the ISFET gate, or an electrode coated with an ion selective film.
Can be On the other hand, MOSF formed on the same substrate
The ET has the same semiconductor parameters as the ISFET because it is made of the same metal material and gate insulating film as the ISFET. Therefore, the temperature characteristics of each semiconductor parameter are the same, and the temperature can be completely compensated by taking the difference between the two.
本発明の望ましい実施例では、シリコン基板の表面又は
表面近傍に、ある間隔をおいて、該シリコンとは異なる
伝導形の領域を二対設けソースおよびドレインとする。
二対の該領域にわたつてシリコン表面に絶縁膜を形成
し、これをゲート絶縁膜とし、該ゲート絶縁膜上にゲー
ト電極を一対設けた電界効果トランジスタ（FET）を同
一基板上に２個形成する。一方のFETにはゲート電極と
して上部表面に酸化層を設けた白金族金属を設け、さら
にイオン選択性膜を被覆した電極を設ける。他方のFET
にはゲート電極として白金族金属あるいは上部表面に酸
化層を設けた白金族金属を用い、さらにゲート電極上部
には耐水膜を設ける。かくして差動型半導体化学センサ
を構成する。In the preferred embodiment of the present invention, two pairs of regions having a conductivity type different from that of silicon are provided at or near the surface of the silicon substrate at a certain interval.
Two field effect transistors (FETs) are formed on the same substrate by forming an insulating film on the silicon surface across two pairs of the regions, using this as a gate insulating film, and providing a pair of gate electrodes on the gate insulating film. To do. One of the FETs is provided with a platinum group metal having an oxide layer on the upper surface as a gate electrode, and further an electrode coated with an ion selective film. Other FET
As the gate electrode, a platinum group metal or a platinum group metal having an oxide layer provided on the upper surface is used, and a water resistant film is further provided on the gate electrode. Thus, a differential type semiconductor chemical sensor is constructed.
本発明の望ましい実施例では、ゲート絶縁膜はSiO2ある
いはSiO2膜上にSi3N4膜を積層した膜である。また、適
用し得る白金族金属は、ロジウム，ルテニウム，イリジ
ウムまたは白金である。In the preferred embodiment of the present invention, the gate insulating film is SiO 2 or a film obtained by laminating a Si 3 N 4 film on the SiO 2 film. The applicable platinum group metal is rhodium, ruthenium, iridium or platinum.
本発明の一実施例を第１図により説明する。第１図はカ
リウムイオン測定用ISFET（K+ISFET）の断面構造を示し
ている。センサチツプ９におけるｐ型Si基板１上にヒ素
をイオン注入して形成したｎ＋拡散層2a〜2dを設け各FE
Tのソース（2a,2c）とドレイン（2b,2d）とした。ISFET
とMOSFETのゲート絶縁膜は等しくSiO2膜3,Si3N4層４を
積層した構造とした。ISFET側には、上部表面に酸化白
金層5aを設けた白金6aをゲート電極とし、さらにポリ塩
化ビニルを母材として可塑剤及びイオン感応物質である
バリノマイシンを分散させたカリウムイオン選択性膜７
を形成した。この膜７は液体試料受入用凹部を有する。An embodiment of the present invention will be described with reference to FIG. Figure 1 shows the cross-sectional structure of an ISFET for potassium ion measurement (K + ISFET). Each of the FEs is provided with n + diffusion layers 2a to 2d formed by ion-implanting arsenic on the p-type Si substrate 1 in the sensor chip 9.
The source (2a, 2c) and drain (2b, 2d) of T were used. ISFET
And the gate insulating film of the MOSFET have the same structure in which the SiO 2 film 3 and the Si 3 N 4 layer 4 are laminated. On the ISFET side, platinum 6a having a platinum oxide layer 5a on the upper surface is used as a gate electrode, and polyvinyl chloride is used as a base material, and a plasticizer and a valinomycin which is an ion-sensing substance are dispersed in the potassium ion selective membrane 7
Was formed. The membrane 7 has a liquid sample receiving recess.
一方、MOSFET側は、ISFETと同じ材質の白金6bをゲート
電極とし、この白金層には酸化白金層5bを形成し、さら
に上部には溶液から保護するための耐水性膜であるポリ
イミド膜８を形成した。On the other hand, on the MOSFET side, platinum 6b made of the same material as ISFET is used as a gate electrode, a platinum oxide layer 5b is formed on this platinum layer, and a polyimide film 8 which is a water resistant film for protecting it from the solution is further formed on the platinum layer. Formed.
第２図に第１図に示したセンサチツプを実装した図を示
す。センサチツプ９の先端にISFET10およびMOSFET11を
並べて配置し、センサ出力端子12をチツプ反対側に配置
した。出力端子12はボンデイングワイヤ13を通して差動
増幅器を有する外部測定回路に接続されたリード線14に
接続している。これら電気的配線部分は弗素樹脂チユー
ブ15とエポキシ樹脂16によつて保護する。外部測定回路
により、出力電圧もしくは出力電流の差信号を得て、カ
リウムイオン濃度を演算し、表示する。FIG. 2 shows a diagram in which the sensor chip shown in FIG. 1 is mounted. An ISFET 10 and a MOSFET 11 are arranged side by side at the tip of the sensor chip 9, and a sensor output terminal 12 is arranged on the opposite side of the chip. The output terminal 12 is connected through a bonding wire 13 to a lead wire 14 which is connected to an external measuring circuit having a differential amplifier. These electric wiring portions are protected by a fluorine resin tube 15 and an epoxy resin 16. An output voltage or output current difference signal is obtained by an external measuring circuit, and the potassium ion concentration is calculated and displayed.
第３図に第２図の装置を用いたときのカリウムイオンに
対するセンサの応答を示す。結果から感度として57mV/d
ecadeが得られた。FIG. 3 shows the response of the sensor to potassium ions when using the apparatus of FIG. As a result, sensitivity of 57 mV / d
I got an ecade.
第４図には温度変化に対する出力電圧変化を示す。直線
Ａは本センサにおけるISFET単体のときの温度特性を示
す。一方、直線Ｂは本発明を適用し同一基板上に形成し
たMOSFETとの出力差をとるようにして測定したもので、
温度係数−0.05mV/℃とISFET単体で測定した場合に比べ
温度係数が小さい。FIG. 4 shows changes in output voltage with respect to changes in temperature. The straight line A shows the temperature characteristic of the ISFET alone in this sensor. On the other hand, the straight line B is obtained by applying the present invention and measuring the output difference from the MOSFET formed on the same substrate.
The temperature coefficient is -0.05 mV / ° C, which is smaller than the temperature coefficient measured by ISFET alone.
本発明によれば、従来のISFET単体で問題であつた温度
変化に基づく測定誤差を差動測定により補償できるの
で、液体試料中のイオン濃度を高精度で測定できる。According to the present invention, since the measurement error due to the temperature change, which is a problem in the conventional ISFET alone, can be compensated by the differential measurement, the ion concentration in the liquid sample can be measured with high accuracy.
第１図は本発明の一実施例のカリウムセンサの断面構造
を示す図、第２図は第１図のセンサチツプの実装図、第
３図は本発明に基づくセンサのカリウム応答を示す図、
第４図は本発明のセンサの温度特性を示す図である。 １……ｐ型Si基板、３……SiO2、４……Si3N4、５……
酸化白金層、６……白金、７……イオン選択性膜、８…
…耐水膜、９……センサチツプ、10……ISFET、11……M
OSFET、12……出力端子。FIG. 1 is a diagram showing a sectional structure of a potassium sensor according to an embodiment of the present invention, FIG. 2 is a mounting diagram of the sensor chip shown in FIG. 1, and FIG. 3 is a diagram showing a potassium response of a sensor according to the present invention.
FIG. 4 is a diagram showing temperature characteristics of the sensor of the present invention. 1 ... p-type Si substrate, 3 ... SiO 2 , 4 ... Si 3 N 4 , 5 ...
Platinum oxide layer, 6 ... Platinum, 7 ... Ion selective membrane, 8 ...
… Water resistant film, 9 …… Sensor chip, 10 …… ISFET, 11 …… M
OSFET, 12 ... Output terminal.
Claims (1)
ースとドレインの対をシリコン基板に二対形成し、この
シリコン基板上に共通のゲート絶縁膜を形成し、このゲ
ート絶縁膜上には一方のソースとドレインの対に対応す
る第１のゲート電極と他方のソースとドレインの対に対
応する第２のゲート電極を設け、上記第１と第２のゲー
ト電極を表面に酸化層を有する同一材質の白金族金属で
形成し、上記第１のゲート電極上にはイオン感応膜を設
け、上記第２のゲート電極上には耐水性膜を設けたこと
を特徴とする差動型半導体化学センサ。1. A pair of a source and a drain for forming a field effect transistor are formed on a silicon substrate, a common gate insulating film is formed on the silicon substrate, and one gate insulating film is formed on the gate insulating film. The same material having a first gate electrode corresponding to the pair of source and drain and a second gate electrode corresponding to the other pair of source and drain, and having an oxide layer on the surface of the first and second gate electrodes Of the platinum group metal of claim 1, wherein an ion sensitive film is provided on the first gate electrode and a water resistant film is provided on the second gate electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63023700A JPH0684951B2 (en) | 1988-02-05 | 1988-02-05 | Differential type semiconductor chemical sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63023700A JPH0684951B2 (en) | 1988-02-05 | 1988-02-05 | Differential type semiconductor chemical sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01201152A JPH01201152A (en) | 1989-08-14 |
| JPH0684951B2 true JPH0684951B2 (en) | 1994-10-26 |
Family
ID=12117661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63023700A Expired - Lifetime JPH0684951B2 (en) | 1988-02-05 | 1988-02-05 | Differential type semiconductor chemical sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0684951B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4669213B2 (en) | 2003-08-29 | 2011-04-13 | 独立行政法人科学技術振興機構 | Field effect transistor, single electron transistor and sensor using the same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57161541A (en) * | 1981-03-31 | 1982-10-05 | Toshiba Corp | Ion sensor |
| JPS6073353A (en) * | 1983-09-30 | 1985-04-25 | Hitachi Ltd | Chemical fet sensor |
-
1988
- 1988-02-05 JP JP63023700A patent/JPH0684951B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01201152A (en) | 1989-08-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4218298A (en) | Selective chemical sensitive FET transducer | |
| US4508613A (en) | Miniaturized potassium ion sensor | |
| US4739380A (en) | Integrated ambient sensing devices and methods of manufacture | |
| US6617190B2 (en) | A-WO3-gate ISFET devices and method of making the same | |
| GB2096824A (en) | Chemically sensitive field effect transistor | |
| US5250168A (en) | Integrated ion sensor | |
| JP2514280B2 (en) | Integrated ion sensor | |
| JPH0684951B2 (en) | Differential type semiconductor chemical sensor | |
| JP3167022B2 (en) | Gas sensor | |
| JPH0469338B2 (en) | ||
| JPS59176662A (en) | Semiconductor sensor | |
| JPS6326569A (en) | Ion selective electrode device | |
| US8410530B2 (en) | Sensitive field effect transistor apparatus | |
| JPH05312778A (en) | Ion concentration sensor | |
| JPS62110145A (en) | Environment detector and manufacture thereof | |
| JPS58167951A (en) | Chlorine ion sensor | |
| JPH0740208Y2 (en) | Sensor for specimen component detection | |
| JPH0452409B2 (en) | ||
| JPS6111652A (en) | Field effect type semiconductor sensor | |
| GB2162997A (en) | A fluoride ion sensitive field effect transistor | |
| JPH0612529Y2 (en) | Biosensor and its sensor plate | |
| JPH029306B2 (en) | ||
| JPS6044617B2 (en) | Ion concentration measuring device | |
| JP2999522B2 (en) | Ion sensor | |
| JPH0429974B2 (en) |