JP2526689B2 - Semiconductor sensor and driving method thereof - Google Patents
Semiconductor sensor and driving method thereofInfo
- Publication number
- JP2526689B2 JP2526689B2 JP2045534A JP4553490A JP2526689B2 JP 2526689 B2 JP2526689 B2 JP 2526689B2 JP 2045534 A JP2045534 A JP 2045534A JP 4553490 A JP4553490 A JP 4553490A JP 2526689 B2 JP2526689 B2 JP 2526689B2
- Authority
- JP
- Japan
- Prior art keywords
- diode
- sensor
- conductor
- measured
- isfet
- 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
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Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、液体中の化学物質を測定する半導体センサ
とその駆動方法に関し、特にイオン感応性電界効果トラ
ンジスタを用いた半導体センサとその駆動方法に関す
る。TECHNICAL FIELD The present invention relates to a semiconductor sensor for measuring a chemical substance in a liquid and a driving method thereof, and more particularly to a semiconductor sensor using an ion sensitive field effect transistor and a driving method thereof. Regarding
［従来の技術］ 従来、イオン感応性電界効果トランジスタ（Ion Sens
itive Field Effect Transistor,以下、ISFETと略
す。）は、液体中のイオンや有機物を検出できるセンサ
として知られている。このISFETは、半導体ICと同様の
製造方法で作られるため、小型化、大量生産が可能で、
種々のイオン感応膜や酵素固定化膜と組み合わせること
により、特定のイオンや有機物を検出可能なセンサが作
製でき、複数のセンサを同一チップ上に形成して、マル
チセンサとすることも可能である。さらに、電気素子を
搭載することも勿論可能である。この電気素子の一つと
して、同一チップ上に温度測定用ダイオードを設け、被
測定溶液の温度を測定することも行われている。[Prior Art] Conventionally, an ion sensitive field effect transistor (Ion Sens
Positive Field Effect Transistor, hereinafter abbreviated as ISFET. ) Is known as a sensor that can detect ions and organic substances in a liquid. Since this ISFET is manufactured by the same manufacturing method as semiconductor ICs, it can be miniaturized and mass-produced.
By combining various ion-sensitive membranes and enzyme-immobilized membranes, it is possible to fabricate a sensor that can detect specific ions and organic substances, and it is also possible to form multiple sensors on the same chip to make a multi-sensor. . Further, it is of course possible to mount an electric element. As one of the electric elements, a temperature measuring diode is provided on the same chip to measure the temperature of the solution to be measured.
［発明が解決しようとする課題］ しかしながら、従来、温度測定用のダイオードのｐ−
ｎ接合部は、ISFETのセンサ領域と離れて設けられてお
り、センサ部の温度を正確に測ることは困難であり、ま
た被測定溶液が微量になった場合、ISFETのセンサ部分
だけが溶液中にあり、温度測定用のダイオードのｐ−ｎ
接合部は溶液の外になり、溶液の温度を測定できないと
いう欠点も生じた。この欠点をなくすためには、ダイオ
ードのｐ−ｎ接合部をISFETのセンサ部の近傍に設け、
被測定溶液に接するようにさせることが必要になる。し
かし、ｐ−ｎ接合が溶液に接した場合、溶液が電位やイ
オン濃度によりダイオード特性が影響を受け、溶液の温
度を精度良く測定することは困難であった。[Problems to be Solved by the Invention] However, p- of a diode for temperature measurement has heretofore been used.
The n-junction is provided apart from the ISFET sensor area, so it is difficult to measure the temperature of the sensor accurately, and when the solution to be measured becomes very small, only the ISFET sensor is in solution. Pn of the diode for temperature measurement
There was also a drawback that the joint was outside the solution and the temperature of the solution could not be measured. In order to eliminate this defect, a diode pn junction is provided near the ISFET sensor,
It is necessary to bring it into contact with the solution to be measured. However, when the pn junction comes into contact with the solution, the diode characteristics of the solution are affected by the potential and the ion concentration, and it is difficult to measure the temperature of the solution with high accuracy.
本発明は、このような課題に鑑みて創案されたもの
で、被測定溶液の温度を正確に測定することが可能な半
導体センサおよびその駆動方法を提供することを目的と
する。The present invention has been devised in view of such a problem, and an object thereof is to provide a semiconductor sensor capable of accurately measuring the temperature of a solution to be measured and a driving method thereof.
［課題を解決するための手段］ 本発明は、センサチップ上にイオン感応性電界効果ト
ランジスタおよびダイオードが設けられ、該ダイオード
の少なくとも接合部分の表面が絶縁体を介して導電体で
覆われていることを特徴とする半導体センサ、およびこ
の半導体センサを用いて、イオン感応性電界効果トラン
ジスタのセンサ領域とダイオードの接合部分を被測定液
体に浸し、ダイオードの表面の導電体にダイオードの一
方の電極と等しい電位を与えると共に、この導電体を被
測定液体の電位を決める疑似参照電極として使用するこ
とを特徴とする半導体センサの駆動方法である。[Means for Solving the Problems] In the present invention, an ion-sensitive field effect transistor and a diode are provided on a sensor chip, and at least the surface of a junction portion of the diode is covered with a conductor via an insulator. A semiconductor sensor characterized by that, and by using this semiconductor sensor, the junction area between the sensor region of the ion-sensitive field effect transistor and the diode is immersed in the liquid to be measured, and the conductor on the surface of the diode is connected to one electrode of the diode. A method for driving a semiconductor sensor is characterized in that an equal electric potential is applied and this conductor is used as a pseudo reference electrode for determining the electric potential of a liquid to be measured.
［作用］ 本発明の半導体センサおよびその駆動方法において
は、温度センサとなるダイオードが液体の成分を測定す
るISFETの近傍に置かれるため、被測定溶液の温度を測
定することができる。また、ダイオードの表面は絶縁体
を介して導電体が設けられ、かつ、この導電体がダイオ
ードの一方の電極に接続されているため、この電極の電
位を一定にすることにより、ダイオードの特性が液体の
電位変化や成分変化による影響をうけることがなく、精
度の良い測定が可能となる。また、このダイオードの表
面に設けられた導電体は、液体の電位を決定するための
疑似参照電極として使用でき、小型の半導体センサが実
現できる。[Operation] In the semiconductor sensor and the method for driving the same according to the present invention, the temperature sensor can be used to measure the temperature of the solution to be measured because the diode serving as the temperature sensor is placed in the vicinity of the ISFET that measures the liquid component. Further, a conductor is provided on the surface of the diode through an insulator, and this conductor is connected to one electrode of the diode. Therefore, by keeping the potential of this electrode constant, the characteristics of the diode are improved. Accurate measurement is possible without being affected by changes in liquid potential and changes in components. Moreover, the conductor provided on the surface of the diode can be used as a pseudo reference electrode for determining the potential of the liquid, and a small semiconductor sensor can be realized.
［実施例］ 以下、本発明の一実施例について図面を参照して詳細
に説明する。[Embodiment] An embodiment of the present invention will be described in detail below with reference to the drawings.
第１図は、本発明の一実施例の平面図で、１はISFET
のドレイン電極、２はISFETのソース電極、３はダイオ
ードのアノード電極、４はダイオードのカソード電極、
５は導電体、６はISFETのセンサ領域、７はダイオード
のｐ−ｎ接合部である。同図からわかるように、ダイオ
ードのｐ−ｎ接合部はISFETのセンサ領域の近傍に設け
られ、被測定液体と５の導電体を介して接するようにな
っている。FIG. 1 is a plan view of an embodiment of the present invention, in which 1 is ISFET.
Drain electrode, 2 is an ISFET source electrode, 3 is a diode anode electrode, 4 is a diode cathode electrode,
Reference numeral 5 is a conductor, 6 is a sensor region of the ISFET, and 7 is a diode pn junction. As can be seen from the figure, the pn junction of the diode is provided in the vicinity of the sensor region of the ISFET and is in contact with the liquid to be measured via the conductor 5.
第２図は、第１図のＡ−Ａ′線による断面図で、５は
導電体、８はサファイア、９はｎ型シリコン、10はp-型
シリコン、11はｐ型シリコン、12は酸化シリコン、13は
窒化シリコン、14は酸素固定化膜、15はアルブミン膜で
ある。酸素固定化膜14としてグルコースオキシダーゼを
固定化した膜を用い、上記の２つのISFETの出力の差を
測定することにより、被測定液体中のグルコース（ぶど
う糖）濃度が測定できる。2 is a sectional view taken along the line AA 'in FIG. 1, 5 is a conductor, 8 is sapphire, 9 is n-type silicon, 10 is p - type silicon, 11 is p-type silicon, and 12 is oxidized. Silicon, 13 is silicon nitride, 14 is an oxygen immobilization film, and 15 is an albumin film. By using a film on which glucose oxidase is immobilized as the oxygen immobilization film 14 and measuring the difference between the outputs of the above two ISFETs, the glucose (glucose) concentration in the liquid to be measured can be measured.
第３図は本発明の半導体センサの駆動方法の一実施例
で、図において、５は導電体、16はISFET、17はダイオ
ード、18は被測定液体、19は定電流源、20は抵抗、21は
オペアンプ、22はアルブミン膜が形成されたISFETのソ
ースホロワ回路の出力１、23は酵素固定化膜が形成され
たISFETのソースホロワ回路の出力２、24は定電流源で
駆動された場合のｐ−ｎ接合間の電圧出力３、25は＋電
源、26は−電源である。FIG. 3 shows an embodiment of a method for driving a semiconductor sensor of the present invention. In the figure, 5 is a conductor, 16 is ISFET, 17 is a diode, 18 is a liquid to be measured, 19 is a constant current source, 20 is a resistor, 21 is an operational amplifier, 22 is the output 1 of the source follower circuit of the ISFET where the albumin film is formed, 23 is the output 2 of the source follower circuit of the ISFET where the enzyme immobilization film is formed, and 24 is the p when driven by a constant current source. The voltage outputs 3 and 25 between the −n junctions are + power supplies, and 26 is a −power supply.
第３図では導電体５の電位をアース電位としている
が、一定電圧であれば適当な値を選ぶことができる。ダ
イオード17の順方向電圧は一定の電流を長した場合、温
度変化に対してほぼ直線的に変化する。また、その表面
は導電体５、例えば金で覆われており、一定電圧に固定
されているため、被測定液体18の成分変化および電位変
化の影響を受けることなく、ISFET近傍の被測定液体の
温度を測定できる。また導電体５は、被測定液体18の電
位を固定する疑似参照電極としても働き、よく知られて
いるように、ソースホロワ回路でISFETを駆動し、２つ
のISFETの出力の差を測定することにより、被測定溶液1
8中の特定の成分、例えば上記の一実施例ではグルコー
スの濃度を測定することができる。Although the electric potential of the conductor 5 is set to the earth potential in FIG. 3, an appropriate value can be selected if the electric potential is constant. The forward voltage of the diode 17 changes almost linearly with a change in temperature when a constant current is applied. Further, since the surface thereof is covered with the conductor 5, for example, gold and fixed to a constant voltage, the liquid under measurement in the vicinity of the ISFET is not affected by the component change and the potential change of the liquid under measurement 18. Can measure temperature. Further, the conductor 5 also functions as a pseudo reference electrode for fixing the potential of the liquid to be measured 18, and as is well known, by driving the ISFET with a source follower circuit and measuring the difference between the outputs of the two ISFETs. , Solution to be measured 1
It is possible to measure the concentration of a particular component in 8, for example glucose in one example above.
［発明の効果］ 以上、説明したとおり、本発明によれば、ISFETのセ
ンサ近傍の被測定液体の温度を精度良く測定でき、か
つ、疑似参照電極が一体化された微小な半導体センサを
実現することができる。[Effects of the Invention] As described above, according to the present invention, it is possible to accurately measure the temperature of the liquid to be measured in the vicinity of the sensor of the ISFET and to realize a minute semiconductor sensor in which a pseudo reference electrode is integrated. be able to.
第１図は本発明の一実施例の平面図、第２図は第１図の
Ａ−Ａ′線による断面図、第３図は本発明による半導体
センサの駆動回路図である。 １……ドレイン電極、２……ソース電極 ３……アノード電極、４……カソード電極 ５……導電体、６……センサ領域 ７……ダイオードのｐ−ｎ接合部 ８……サファイア、９……ｎ型シリコン 10……p-型シリコン、11……ｐ型シリコン 12……酸化シリコン、13……窒化シリコン 14……酵素固定化膜、15……アルブミン膜 16……ISFET、17……ダイオード 18……被測定液体、19……定電流源 20……抵抗、21……オペアンプ 22……出力１、23……出力２ 24……出力３、25……＋電源 26……−電源1 is a plan view of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA 'in FIG. 1, and FIG. 3 is a drive circuit diagram of a semiconductor sensor according to the present invention. 1 ... Drain electrode, 2 ... Source electrode 3 ... Anode electrode, 4 ... Cathode electrode 5 ... Conductor, 6 ... Sensor region 7 ... Diode pn junction 8 ... Sapphire, 9 ... … N-type silicon 10 …… p - type silicon, 11 …… p-type silicon 12 …… Silicon oxide, 13 …… Silicon nitride 14 …… Enzyme-immobilized membrane, 15 …… Albumin membrane 16 …… ISFET, 17 …… Diode 18 …… Liquid to be measured, 19 …… Constant current source 20 …… Resistance, 21 …… Opamp 22 …… Output 1, 23 …… Output 2 24 …… Output 3, 25 …… ＋ Power supply 26 …… － Power supply
Claims (2)
ランジスタおよびダイオードが設けられ、該ダイオード
の少なくとも接合部分の表面が絶縁体を介して導電体で
覆われていることを特徴とする半導体センサ。1. A semiconductor sensor characterized in that an ion-sensitive field effect transistor and a diode are provided on a sensor chip, and at least a surface of a junction portion of the diode is covered with a conductor via an insulator.
サ領域とダイオードの接合部分を被測定液体に浸し、ダ
イオードの表面の導電体にダイオードの一方の電極と等
しい電位を与えると共に、この導電体を被測定液体の電
位を決める疑似参照電極として使用することを特徴とす
る請求項（１）に記載の半導体センサの駆動方法。2. The junction area between the sensor region of the ion-sensitive field effect transistor and the diode is dipped in a liquid to be measured, and a potential equal to that of one electrode of the diode is applied to a conductor on the surface of the diode, and the conductor is covered. The method for driving a semiconductor sensor according to claim 1, wherein the driving method is used as a pseudo reference electrode for determining the potential of the measurement liquid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2045534A JP2526689B2 (en) | 1990-02-28 | 1990-02-28 | Semiconductor sensor and driving method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2045534A JP2526689B2 (en) | 1990-02-28 | 1990-02-28 | Semiconductor sensor and driving method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03249557A JPH03249557A (en) | 1991-11-07 |
| JP2526689B2 true JP2526689B2 (en) | 1996-08-21 |
Family
ID=12722057
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2045534A Expired - Lifetime JP2526689B2 (en) | 1990-02-28 | 1990-02-28 | Semiconductor sensor and driving method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2526689B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4065855B2 (en) | 2004-01-21 | 2008-03-26 | 株式会社日立製作所 | Biological and chemical sample inspection equipment |
-
1990
- 1990-02-28 JP JP2045534A patent/JP2526689B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03249557A (en) | 1991-11-07 |
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