JPS6073352A - Chemical fet sensor - Google Patents
Chemical fet sensorInfo
- Publication number
- JPS6073352A JPS6073352A JP58180234A JP18023483A JPS6073352A JP S6073352 A JPS6073352 A JP S6073352A JP 58180234 A JP58180234 A JP 58180234A JP 18023483 A JP18023483 A JP 18023483A JP S6073352 A JPS6073352 A JP S6073352A
- Authority
- JP
- Japan
- Prior art keywords
- film
- sensor
- oxide film
- chemical
- wiring
- 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
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Biochemistry (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Molecular Biology (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は、血液分析装置用センサなど試料溶液中の化学
物質の濃度を測定するための化学FETセンサに関する
。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a chemical FET sensor for measuring the concentration of a chemical substance in a sample solution, such as a sensor for a blood analyzer.
化学FETセンサとMOSFETを同一半導体基板上に
形成したものに
[A、l(AEMMERLI 、J、 JANATA。A chemical FET sensor and a MOSFET formed on the same semiconductor substrate [AEMMERLI, J, JANATA.
H6N、 Bl(OWN Anal、 Chim、 A
cta、、 144(1982)115−121Jがあ
る。この化学FETセンサのゲート部分の構造は、イオ
ン選択性の微小電極をゲート絶縁膜上に取り付けたもの
で、この微小電極部分のみを測定溶液につければ測定出
来る。ところで、[5TANLEY D。H6N, Bl(OWN Anal, Chim, A
cta, 144 (1982) 115-121J. The structure of the gate portion of this chemical FET sensor is such that an ion-selective microelectrode is attached to a gate insulating film, and measurement can be performed by immersing only this microelectrode portion in a measurement solution. By the way, [5TANLEY D.
Mo5s、CURTiS C,JO)INsON、JI
几1JANATA、1EEE T几ANSACTION
SON’BiOMEDICAL ENGiNEER,L
NG。Mo5s, CURTiSC, JO) INsON, JI
几1JANATA, 1EEE T几ANSACTION
SON'BiOMEDICAL ENGiNEER, L
NG.
VOL、 BME−25、隘1 、49 (1978)
Jニ報告されでいる工うな、FETのゲート絶縁膜の上
に直接イオン感応膜を付けた構造の化学FETセンサを
前述のようにM OS L’! E Tと一諸に半導体
基板上に形成しようとすると、化学FETセンサはゲー
ト部分を直接測定溶液につけなければならないので、M
OSFETの表面まで溶液につかることになり、従来の
MO8F’ETの構造では、すぐ腐食を起こし動作に異
常をきたす。このため従来のMO8Li”ETの構造で
は同一半導体基板上に化学FIDTセンサと一諸に形成
して使用することが出来なかった。VOL, BME-25, No. 1, 49 (1978)
As previously reported, a chemical FET sensor with a structure in which an ion-sensitive film is directly attached on the gate insulating film of the FET is used as a MOS L'! If a chemical FET sensor is to be formed on a semiconductor substrate along with E T, the gate part must be directly immersed in the measurement solution, so M
The surface of the OSFET will be immersed in the solution, and in the conventional MO8F'ET structure, corrosion will occur immediately and abnormal operation will occur. For this reason, the conventional MO8Li"ET structure could not be used together with a chemical FIDT sensor on the same semiconductor substrate.
本発明の目的は、化学FETセンサから得られる信号を
処理する回路を化学FETセンサと一諸に同一半導体基
板上に形成して、センサチップ表面を直接、被測定溶液
に接触させることが出来る索子構造を提供することにあ
る。An object of the present invention is to form a circuit for processing signals obtained from a chemical FET sensor on the same semiconductor substrate as the chemical FET sensor, and to make it possible to bring the surface of the sensor chip into direct contact with a solution to be measured. The purpose is to provide a child structure.
化学F、 E TセンサとMO8FETセンサを同一半
導体基板上に形成し、MOSFETの表面部分に耐水膜
などをつければ一応の保護はできるが、耐水膜がついで
いる箇所とついてない箇所の境界部分から溶液が浸入し
、 Aj配線などの腐食が発生する。また、この耐水膜
が厚いと化学FETセンサと溶液間の熱伝導とMOSF
ETと溶液間の熱伝導に大きな差が生じるため、M、0
8FETによる温度補償が出来なくなる。このためMO
3F’ETの膜構造は化学FETと類似した構造とする
必要がある。また重責が起こりやすいAI配線は採用し
ない構成としなければならない。そのために本発明では
配線及びゲート電極として全てpoly−8i(ポリシ
リコン)またはTa+W等のシリサイドを採用する。そ
の半導体基板表面の第一層目の酸化膜中に配線を形成し
、センサチップ全体に第二層目として5iBN4等の耐
水膜を形成した。さらに化学FETセンサ部分だけ、ま
たはセンサチップ全体に被測定化学物質に感応する感応
膜を形成すれiJ[408FETに耐水性をもたせ、測
定溶液に接触させることができる。Chemical F, ET Sensors and MO8FET sensors are formed on the same semiconductor substrate and a water-resistant film is applied to the surface of the MOSFET to provide some protection, but from the boundary between the areas where the water-resistant film is applied and the areas where it is not. The solution will enter, causing corrosion of AJ wiring, etc. In addition, if this water-resistant film is thick, heat conduction between the chemical FET sensor and the solution will be reduced.
Since there is a large difference in heat conduction between ET and the solution, M,0
Temperature compensation by 8FET becomes impossible. For this reason, M.O.
The membrane structure of the 3F'ET needs to be similar to that of a chemical FET. In addition, the configuration must not include AI wiring, which is likely to cause heavy liability. For this reason, in the present invention, poly-8i (polysilicon) or silicide such as Ta+W is used for all wiring and gate electrodes. Wiring was formed in the first layer of oxide film on the surface of the semiconductor substrate, and a water-resistant film such as 5iBN4 was formed as the second layer over the entire sensor chip. Furthermore, by forming a sensitive film sensitive to the chemical substance to be measured only on the chemical FET sensor portion or on the entire sensor chip, the iJ[408 FET can be made water resistant and brought into contact with the measurement solution.
以下、本発明の一実施例を第1図により説明する。第1
図はp形Si基板上に形成した化学FETセンサ及びM
OSFETの素子の断面を示したものであるOp形Si
基板1上に化学F’ETセンサとMOSFETを、分離
して形成するためにp形活散層3及び分離部分だけに酸
化膜5を厚く形成するLOGO8(Local 0xi
dization ofSilicon )によシ素子
分離をおこなった。An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a chemical FET sensor formed on a p-type Si substrate and M
Op type Si which shows the cross section of OSFET element
In order to separately form a chemical F'ET sensor and a MOSFET on the substrate 1, a thick oxide film 5 is formed only on the p-type active layer 3 and the separated part.
The elements were separated by dization of silicon.
MOSFETのゲート電極としてpoly−8iゲート
電極6を形成し、さらに各素子間MO8FETどうしま
たはMOSFETと化学FETセンサとの配線もpol
y−8i配線4で形成した。各素子ともnチャネルFg
Tなのでシんをドープしたpoly−8iを使用したが
、他の配線としてTaやWのシリサイドも可能である。A poly-8i gate electrode 6 is formed as the gate electrode of the MOSFET, and the wiring between the MO8FETs between each element or between the MOSFET and the chemical FET sensor is also formed as a pol.
It was formed with y-8i wiring 4. Each element has n-channel Fg
Since T is used, poly-8i doped with phosphor is used, but silicide of Ta or W is also possible as other wiring.
図右側の素子の化学F g Tセンサの構造と左側の素
子のMOSFETの構造と異なる点は、MOSFETの
ゲート電極に相等するものが化学FETセンサにはない
だけで、第一層目に酸化膜5.第二層目に耐水絶縁膜と
してのSi3N4膜7.第三層目にここではpH応答す
る感応膜としてTa205膜8をゲート部分に層状に形
成しでいる。 n+拡散層2によって形成したソース及
びドレインを他の素子と接続する配線としてのpoly
−8i 配#ii4を第一層中に形成した。MO’5F
ETでも同様に第一層の酸化膜中に配線及びゲート電極
のpoly−8tを形成し、第二層目にSi3N4膜7
を形成しセンサチップを被測定溶液につけられるよう保
護している。さらに、第三層にpH感応膜とし、でのT
a205膜8を形成している。第一層に配線及びゲート
電極を形成したため、pH測定用化学FETセンサとM
OSFETとの構造の違いはゲート電極の有無だけとな
っている。MOSFETのドレイン電流制御はゲート電
極の電位でおこなえる〇一方、化学FETセンサは、感
応膜側を被測定溶液に接触させ、飽和カロメル電極等の
参照電極で被測定溶液に電位を与えることによシトレイ
ン電流を規定するが、この電位にさらにここでは被測定
溶液のpH値によシ溶液とTa2O,膜との界面に生じ
る電位変化が加わる。この電位変化によりpH測定用化
学FETセンサが動作する。The difference between the structure of the chemical F g T sensor on the right side of the figure and the structure of the MOSFET on the left side is that the chemical FET sensor does not have an equivalent to the gate electrode of a MOSFET; 5. Si3N4 film as the second layer as a water-resistant insulating film7. As the third layer, a Ta205 film 8 is formed as a layer at the gate portion as a pH-responsive sensitive film. Poly as a wiring connecting the source and drain formed by the n+ diffusion layer 2 to other elements
-8i pattern #ii4 was formed in the first layer. MO'5F
In ET, wiring and gate electrode poly-8T are similarly formed in the first layer of oxide film, and Si3N4 film 7 is formed in the second layer.
to protect the sensor chip from being immersed in the solution to be measured. Furthermore, the third layer is a pH-sensitive film, and the T
A205 film 8 is formed. Since the wiring and gate electrode were formed on the first layer, the chemical FET sensor for pH measurement and M
The only difference in structure from OSFET is the presence or absence of a gate electrode. The drain current of a MOSFET can be controlled by the potential of the gate electrode.On the other hand, a chemical FET sensor can control the drain current by bringing the sensitive membrane side into contact with the solution to be measured and applying a potential to the solution to be measured using a reference electrode such as a saturated calomel electrode. The cell train current is defined, and to this potential is added the potential change that occurs at the interface between the cell solution, Ta2O, and the membrane depending on the pH value of the solution to be measured. This potential change causes the chemical FET sensor for pH measurement to operate.
この素子構造により、pH測定用化学FETセンサとそ
の信号処理用の素子をワンチップ化したときの回路図を
第2図に示す。この回路はゲート電圧が零のときドレイ
ン電流が流扛ないエンノ・ンスメント形のNMO8によ
って構成された差動増幅回路であり、Ql とQ2がダ
イナミック負荷用MO8FETで、Q3とQ4が増幅用
であるが。FIG. 2 shows a circuit diagram when a chemical FET sensor for pH measurement and its signal processing element are integrated into one chip using this element structure. This circuit is a differential amplifier circuit composed of an enhancement type NMO8 in which no drain current flows when the gate voltage is zero, Ql and Q2 are MO8FETs for dynamic load, and Q3 and Q4 are for amplification. but.
Q3だけ化学FETセンサとしている。各素子のチャン
ネル長し、及びチャンネル幅Wの比W/Lの値を、それ
ぞれQ、とQ2では3.Q3を54゜Q4を30 #
Q5 とQ7は6.Q6を12とした。Only Q3 is a chemical FET sensor. The channel length of each element and the value of the ratio W/L of the channel width W are set to 3 for Q and Q2, respectively. Q3 is 54° Q4 is 30 #
Q5 and Q7 are 6. Q6 was set to 12.
このセンサチップを各種のpH値からなる被測定溶液に
接触させ、センサ出力の変化・を詞べた結果を第3図に
示す。センサ出力としてpH7付近では78mV/pH
が得られ、ネルンストの理論式より得られる界面電位変
化58mV/pi((20°C)がこの差動増幅回路に
よシ約1.4倍増幅されて得られた。This sensor chip was brought into contact with solutions to be measured consisting of various pH values, and the results of changes in sensor output are shown in FIG. Sensor output is 78mV/pH around pH7
was obtained, and the interfacial potential change of 58 mV/pi ((20°C) obtained from Nernst's theoretical formula was amplified by about 1.4 times by this differential amplifier circuit.
本発明によれば、Si基板上に化学FETセンサと一諸
にMO8FET素子を形成しでも、そのセンサチップを
被測定溶液につけることが可能となるため、化学FET
センサの信号処理を同一チップ上で出来るようになった
。According to the present invention, even if an MO8FET element is formed together with a chemical FET sensor on a Si substrate, it is possible to immerse the sensor chip in the solution to be measured.
Sensor signal processing can now be performed on the same chip.
第1図は本発明の実施例の化学FETセンサとンサとM
O8li’ETによって構成された差動増幅回路、第3
図は第2図における回路を使い各測定溶液のpH値値化
化よる出力変化を調べたものである。
l・・・p形Si基板、2・・・n+拡散層、3・・・
p拡散層、4・・・poly−8i配線、5・・・酸化
膜、6・・・poly−8iゲート電極、7・・・Si
3N4膜、8・・・11図
箋2図
譬30
0246 P lO12
、HFIG. 1 shows a chemical FET sensor, sensor and M according to an embodiment of the present invention.
Differential amplifier circuit configured by O8li'ET, third
The figure shows an investigation of the output changes caused by converting the pH value of each measurement solution using the circuit shown in FIG. 2. l...p-type Si substrate, 2...n+ diffusion layer, 3...
p diffusion layer, 4... poly-8i wiring, 5... oxide film, 6... poly-8i gate electrode, 7... Si
3N4 membrane, 8...11 Illustration 2 Illustration 30 0246 P lO12 , H
Claims (1)
サの配線とMOSFETの配線及びゲート電極とが、半
導体基板表面の酸化膜中に形成されたことを特徴とする
化学FETセンサ。 2、前記酸化膜の表面にSi3N4等の耐水絶縁膜が形
成されたことを特徴とする特許請求の範囲第1項記載の
化学FETセンサ。[Scope of Claims] 1. A chemical FET sensor characterized in that the chemical FIiliT sensor wiring and the MOSFET wiring and gate electrode formed on the same semiconductor substrate are formed in an oxide film on the surface of the semiconductor substrate. 2. The chemical FET sensor according to claim 1, wherein a water-resistant insulating film such as Si3N4 is formed on the surface of the oxide film.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP58180234A JPS6073352A (en) | 1983-09-30 | 1983-09-30 | Chemical fet sensor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP58180234A JPS6073352A (en) | 1983-09-30 | 1983-09-30 | Chemical fet sensor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS6073352A true JPS6073352A (en) | 1985-04-25 |
Family
ID=16079715
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP58180234A Pending JPS6073352A (en) | 1983-09-30 | 1983-09-30 | Chemical fet sensor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6073352A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0813058A1 (en) * | 1996-06-12 | 1997-12-17 | Siemens Aktiengesellschaft | MOS transistor for biomedical applications |
CN110940706A (en) * | 2018-09-25 | 2020-03-31 | 英飞凌科技股份有限公司 | Gas sensitive Hall device |
-
1983
- 1983-09-30 JP JP58180234A patent/JPS6073352A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0813058A1 (en) * | 1996-06-12 | 1997-12-17 | Siemens Aktiengesellschaft | MOS transistor for biomedical applications |
US5801428A (en) * | 1996-06-12 | 1998-09-01 | Siemens Aktiengesellschaft | MOS transistor for biotechnical applications |
CN110940706A (en) * | 2018-09-25 | 2020-03-31 | 英飞凌科技股份有限公司 | Gas sensitive Hall device |
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