JP2012088118A - Transistor type sensor, and measurement method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transistor type sensor which is preferably used as a biosensor and the like and can perform measurement stably with high accuracy.SOLUTION: A transistor type sensor comprises: a base material; transistor sections each having a function as a thin-film transistor; and a sensor section which is composed of a detecting electrode and an ion-sensitive film made of an insulation material and formed on the detecting electrode. The transistor sections and the sensor section are arranged so that alignment thereof is made on the same surface of the base material. Also, a plurality of the transistor sections is used and the plurality of the transistor sections is electrically connected to a single sensor section.

Description

  The present invention relates to a transistor type sensor that can be suitably used as a biosensor and the like, and a measurement method using the same.

  In recent years, various methods have been developed for testing biologically relevant substances such as DNA, sugar chains, and proteins for the purpose of disease diagnosis, detection of individual differences in drug metabolism, or food or environmental monitoring. In particular, research on biosensors that detect biomolecules using electrical signals is in progress. Recently, a field effect transistor (hereinafter also referred to as “FET”) is used from the viewpoint that electrical signal conversion is fast and the connection between an integrated circuit and a MEMS (Micro Electro Mechanical System) is easy. Much research has been done on biosensors that are used to detect biological responses.

  Conventionally, a biosensor using an FET has a structure in which a gate electrode is removed from a MOSFET and an ion-sensitive film is deposited on an insulating film, which is called “ISFET (Ion Sensitive FET)”. . And it arrange | positions an oxidoreductase, various proteins, DNA, an antigen, or an antibody etc. to an ion sensitive film | membrane, and functions as various biosensors (for example, patent document 1).

  Specifically, an FET used for a biosensor has a source electrode, a drain electrode, and a gate insulating film formed on the surface of a silicon substrate, and a metal electrode on the surface of the gate insulator between the source electrode and the drain electrode. . A DNA probe and alkanethiol are disposed on the surface of the metal electrode. When actually performing the measurement, the metal electrode, the DNA probe and alkanethiol arranged on the surface of the metal electrode, and the reference electrode are arranged in the reaction solution in the measurement cell, When a voltage is applied through the reference electrode, the electrical characteristics of the insulated gate field effect transistor change before and after the binding between the target DNA and the DNA probe contained in the reaction solution, that is, between the source and the drain. By detecting a change in the value of the flowing current, it is possible to detect the presence or absence of extension of the target DNA contained in the reaction solution.

  By the way, a transistor type sensor used in the above-described biosensor or the like generally has a configuration in which one transistor is connected to one ion sensitive film. However, in such a configuration in which the transistor and the ion sensitive film are in a one-to-one relationship, if the transistor does not operate for some reason, or if the transistor operates but has a defective performance, the transistor type There was a problem that accurate data could not be acquired using a sensor.

  The transistor-type sensor used in the above-described biosensor or the like generally has a laminated structure in which the gate electrode constituting the transistor is removed and an ion-sensitive film is deposited on the gate insulating film. It is. However, the transistor type sensor having such a laminated structure has a problem that an ion sensitive film having a wider area cannot be formed because the region where the ion sensitive film can be formed is limited on the transistor. . In addition, in the case of having the above laminated structure, when a sample to be measured is provided on the ion sensitive film, the sample penetrates into the transistor arranged immediately below the ion sensitive film, and the function of the transistor is impaired. There was also a problem. For this reason, there is a problem in that it is difficult to perform stable measurement in the transistor type sensor having the laminated structure. Furthermore, the transistor type sensor having the above laminated structure has also been pointed out that the manufacturing process becomes complicated.

JP 2007-108160 A

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a transistor type sensor that can be suitably used as a biosensor or the like and can perform stable and highly accurate measurement. Is.

  In order to solve the above problems, the present invention provides a sensor having a base material, a transistor portion having a function as a thin film transistor, a detection electrode, and an ion-sensitive film formed on the detection electrode and made of an insulating material. And the transistor part and the sensor part are arranged in parallel on the same surface of the base material, and a plurality of the transistor parts are used. A transistor type sensor is provided in which a plurality of the transistor parts are electrically connected to the sensor part.

According to the transistor-type sensor of the present invention, a plurality of transistor portions are electrically connected to a single sensor portion, so that a plurality of transistor portions do not operate or malfunction. Even if it is included, normal data acquisition can be performed by other transistor portions. In addition, since data obtained by a plurality of transistor portions can be compared and examined, an abnormal value can be easily discriminated, and accurate evaluation can be performed by eliminating this abnormal value. Furthermore, since data acquisition by a plurality of transistor portions is possible, for example, highly accurate evaluation can be performed by statistically processing measurement data obtained in each transistor portion.
Moreover, in the transistor type sensor of the present invention, the transistor part and the sensor part are arranged so as to be arranged in parallel on the same surface of the base material, so that an ion sensitive film is formed in the sensor part. There are few restrictions on the area to be used. Therefore, in the present invention, the ion sensitive film can be formed in a wide area. In addition, since the transistor part and the sensor part are arranged in parallel on the same surface of the base material, when the sample to be measured is applied on the ion sensitive film, the sample Therefore, there is no problem that the function of the transistor portion deteriorates.
For this reason, according to the present invention, it is possible to provide a transistor type sensor capable of stably performing highly accurate measurement.

  In the transistor-type sensor of the present invention, the base material has transparency, the detection electrode has transparency, and the ion-sensitive film has transparency. preferable. As a result, when measuring using the transistor type sensor of the present invention, it is possible not only to measure the voltage change, but also to visually observe the sample applied on the ion sensitive film of the sensor unit with transmitted light. Because it becomes. In addition, in a transistor type sensor having a laminated structure used for a conventional biosensor or the like, in order to visually observe a sample on an ion sensitive film with transmitted light, a transparent semiconductor must be used. There was a restriction that it was not possible. However, in the present invention, since the transistor portion and the sensor portion are arranged so as to be arranged in parallel on the same surface on the base material, visual observation is performed regardless of the type of semiconductor layer used in the transistor portion. There is an advantage that you can.

  Further, the present invention is a measurement method using the transistor type sensor according to the present invention, wherein a data acquisition step of acquiring measurement data by a plurality of the transistor units, and processing the measurement data acquired in the data acquisition step And a data processing step. A measurement method is provided.

  According to the present invention, in the above data acquisition step, measurement data is acquired from a plurality of transistor units included in the transistor type sensor of the present invention, so that it does not operate on a part of the plurality of transistor units, or operates poorly. Even if included, normal value data can be obtained from other transistor portions. Further, since it becomes possible to compare and examine data acquired by a plurality of transistor portions, an abnormal value can be easily determined, and accurate evaluation can be performed by eliminating this abnormal value. Furthermore, by processing the measurement data acquired from the plurality of transistor portions in the data processing step, a highly accurate measurement result can be obtained.

  The transistor type sensor of the present invention is suitably used as a biosensor or the like, and has an effect of being able to perform highly accurate measurement stably.

It is the schematic which shows an example of the transistor type sensor of this invention. It is a schematic sectional drawing which shows the other example of the transistor type sensor of this invention. It is a schematic sectional drawing which shows the other example of the transistor type sensor of this invention. It is a schematic sectional drawing which shows the other example of the transistor type sensor of this invention. It is the schematic explaining the evaluation method of the transistor type sensor of this invention. It is a graph which shows an example of the shift of the threshold voltage of a transistor. It is a table | surface which shows the measurement data by a sensor part. It is the schematic which shows the specific example of the transistor type sensor of this invention.

The present invention relates to a transistor type sensor and a measurement method using the same.
Hereinafter, each invention will be described in order.

A. Transistor type sensor First, the transistor type sensor of the present invention will be described. The transistor-type sensor of the present invention includes a base material, a transistor portion having a function as a thin film transistor, a detection electrode, and a sensor portion having an ion-sensitive film formed on the detection electrode and made of an insulating material, The transistor part and the sensor part are arranged in parallel on the same surface of the base material, and a plurality of the transistor parts are used. A plurality of the transistor portions are electrically connected to the portion.

Such a transistor type sensor of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of a transistor type sensor of the present invention. Here, FIG. 1B is a cross-sectional view taken along the line XX ′ in FIG. As illustrated in FIG. 1A, the transistor type sensor 1 of the present invention includes a base material 10, a transistor unit 20 having a function as a thin film transistor, and a sensor unit 30. Here, as illustrated in FIG. 1B, the sensor unit 30 includes a detection electrode 31 and an ion-sensitive film 32 formed on the detection electrode 31 and made of an insulating material. . Further, the transistor portion 20 illustrated in FIG. 1 includes a thin film transistor having a bottom gate / top contact type structure, and includes a gate electrode 21, a gate insulating layer 22, a semiconductor layer 23, a source electrode 24, and a drain electrode 25. (FIG. 1 (b)).
In such an example, the transistor type sensor 1 of the present invention is configured so that the transistor unit 20 and the sensor unit 30 are arranged in parallel on the same surface of the substrate 10 as illustrated in FIG. As shown in FIG. 1A, a plurality of the transistor portions 20 are used, and a plurality of the transistor portions 20 are provided for the single sensor portion 30 (eight in FIG. 1A). The transistor portion 20 is electrically connected. Here, as illustrated in FIG. 1B, in the transistor type sensor of the present invention, it is usually arranged so that the gate electrode 21 of the transistor unit 20 is connected to the detection electrode 31 of the sensor unit 30. The

According to the transistor-type sensor of the present invention, a plurality of transistor portions are electrically connected to a single sensor portion, so that a plurality of transistor portions do not operate or malfunction. Even if it is included, normal data acquisition can be performed by other transistor portions. In addition, since data obtained by a plurality of transistor portions can be compared and examined, an abnormal value can be easily discriminated, and accurate evaluation can be performed by eliminating this abnormal value. Furthermore, since data acquisition by a plurality of transistor portions is possible, for example, highly accurate evaluation can be performed by statistically processing measurement data obtained in each transistor portion.
Moreover, in the transistor type sensor of the present invention, since the transistor part and the sensor part are arranged in parallel on the same surface of the base material, an ion sensitive film is formed in the sensor part. There are few restrictions on the area. Therefore, in the present invention, the ion sensitive film can be formed in a wide area. In addition, since the transistor part and the sensor part are arranged in parallel on the same surface of the base material, when the sample to be measured is applied on the ion sensitive film, the sample Therefore, there is no problem that the function of the transistor portion deteriorates.
For this reason, according to the present invention, it is possible to provide a transistor type sensor capable of stably performing highly accurate measurement.

The transistor type sensor of the present invention has at least the above-mentioned transistor part, sensor part, and base material, and may have other configurations as necessary.
Hereafter, each structure used for this invention is demonstrated in order.

1. Sensor Unit First, the sensor unit used in the present invention will be described. The sensor unit used in the present invention has a detection electrode and an ion-sensitive film formed on the detection electrode. In addition, the sensor unit used in the present invention is one in which a plurality of transistor units described later are electrically connected.

(1) Ion-sensitive film The ion-sensitive film used in the sensor part is not particularly limited as long as it is made of an insulating material and has sensitivity to desired ions. It can be appropriately selected and used depending on the application and the object to be evaluated using the transistor type sensor of the present invention. Examples of the insulating material used for the sensor unit in the present invention include a silicon oxide film (SiO ₂ ), a silicon nitride film (Si ₃ N ₄ ), a tantalum oxide film (Ta ₂ O ₅ ), or an aluminum oxide film (Al ₂ O). ₃ ). In the present invention, any of these insulating materials can be suitably used.

When the transistor-type sensor of the present invention is used as a biosensor, as the insulating material used for the ion-sensitive membrane, a material capable of arranging a biological substance such as a cell, DNA, sugar chain, or protein is used. Examples of such an insulating material include a silicon oxide film (SiO ₂ ), a silicon nitride film (Si ₃ N ₄ ), a tantalum oxide film (Ta ₂ O ₅ ), and an aluminum oxide film (Al ₂ O ₃ ). be able to.
When the transistor-type sensor of the present invention is used as a biosensor, surface modification for immobilizing DNA proteins and sugar chains may be performed on the surface of the ion sensitive membrane as necessary. Examples of such surface modifications include, for example, methods for forming self-assembled monolayers such as gold thiol reaction, bonding using silane coupling materials, LB films, electrostatic adsorption, physical adsorption, and the like. be able to.

As an aspect in which the ion-sensitive film is formed in the sensor part, an aspect in which each sensor part is formed independently, or an aspect in which the sensor part is formed integrally with some of the components of the transistor part described later. Etc. The ion-sensitive film in the present invention may be formed in any of these embodiments, but is preferably formed in one piece with some of the components of the transistor portion. Since the configuration of the transistor type sensor of the present invention can be further simplified by forming the ion sensitive film in this manner, a transistor type sensor that can be manufactured by a simpler process is provided. Because it can. In the transistor type sensor of the present invention, as an example of an aspect in which the ion sensitive film is formed integrally with a part of the components of the transistor portion, for example, a transistor portion composed of a bottom gate type thin film transistor is used. And a mode in which a transistor portion made of a thin film transistor having a bottom-gate structure is used, and a mode in which the transistor is formed integrally with a passivation layer of the transistor portion. Details of these aspects will be described in detail in the section “4. Configuration of Transistor-Type Sensor” described later.
Note that the term “integrally” means that the ion-sensitive film and a part of the constituent elements of the transistor portion are formed as a single member having both functions.

(2) Detection Electrode Next, the detection electrode used for the sensor unit will be described. The detection electrode used in the present invention functions as an electrode. In the present invention, the gate electrodes of a plurality of transistor portions, which will be described later, are usually formed so as to be connected to the detection electrodes.

  The detection electrode used in the present invention is not particularly limited as long as it functions as an electrode. As a detection electrode used in the present invention, for example, in addition to a general metal material such as Al, a transparent electrode such as ITO can also be used. The thickness of the detection electrode used in the present invention is usually preferably in the range of 50 nm to 500 nm.

As an aspect in which the detection electrode is formed in the sensor part, an aspect in which each sensor part is formed independently, or an aspect in which a part of the components of the transistor part described later is formed integrally. Etc. The detection electrode in the present invention may be formed in any of these embodiments, but is preferably formed integrally with a part of the components of the transistor portion, in particular, the bottom gate type. It is preferable that a transistor portion formed of a thin film transistor having a structure is used and formed integrally with a gate electrode of the transistor portion. Since the configuration of the transistor type sensor of the present invention can be simplified by forming the detection electrode in this manner, a transistor type sensor that can be manufactured by a simpler process is provided. Because you can. Here, the term “as an integral unit” means that the detection electrode and the gate electrode are formed as a single member having both functions.
The details of the aspect in which the detection electrode is formed integrally with the gate electrode will be described in detail in the section of “4. Configuration of transistor type sensor” described later.

(3) Sensor part When measuring using the transistor type sensor of this invention, the sample used as a measuring object is provided on the ion sensitive film | membrane of a sensor part, and the voltage change accompanying this is detected in the transistor part mentioned later. It will be. Here, depending on the use of the transistor type sensor of the present invention, it may be desirable not only to evaluate voltage change but also to simultaneously change the shape of the sample to be measured provided on the ion sensitive film. In particular, when the transistor-type sensor of the present invention is used as a biosensor, biological materials are provided on the ion-sensitive membrane. When evaluating the biological samples, simply evaluate voltage changes. Thus, it may be desirable not only to measure changes in pH and the like, but also to simultaneously evaluate morphological changes over time of biological samples. In such a case, as a method for observing the form of the biological sample on the ion-sensitive membrane, the biological sample is often small in size, such as a cell. More preferably, it can be done. From such a viewpoint, it is preferable that the sensor part used in the present invention is such that the detection electrode and the ion sensitive film have transparency. This is because the biological sample on the ion sensitive membrane can be observed using, for example, an inverted transmission microscope. In this case, it is necessary that the substrate described later also has transparency.
Here, among the materials used for the detection electrode described above, examples of materials that can form a transparent detection electrode include ITO, IZO, and ZnO. In addition, among the insulating materials used for the ion sensitive film described above, examples of materials that can form a transparent ion sensitive film include, for example, SiO ₂ , Si ₃ N ₄ , Ta ₂ O ₅ , Al ₂ O _3. Etc.

  The sensor unit used in the present invention includes at least the detection electrode and the ion sensitive film, but may have other configurations as necessary. The other configuration is not particularly limited as long as the function of the sensor unit is not impaired, and a configuration having a desired function can be appropriately selected and used. As such another configuration, an example of a material suitably used in the present invention is an insulating layer formed between the detection electrode and the ion sensitive film and made of an insulating material. In the case where the insulating layer is formed in the sensor portion, it is preferable that the insulating layer is formed integrally with some of the components of the transistor portion described later from the viewpoint of simplifying the transistor type sensor of the present invention. In particular, it is preferable that a transistor portion formed of a thin film transistor having a bottom-gate structure is used and formed integrally with a gate insulating layer of the transistor portion.

2. Transistor Part Next, the transistor part used in the present invention will be described. The transistor portion used in the present invention has a function as a thin film transistor. In the transistor type sensor of the present invention, a plurality of transistor portions are used, and a plurality of transistor portions are electrically connected to a single sensor portion.

  The transistor portion used in the present invention is not particularly limited as long as it functions as a thin film transistor. Therefore, the transistor portion used in the present invention may be composed of a thin film transistor having a bottom gate type structure, or may be composed of a thin film transistor having a top gate structure. Here, a thin film transistor having a top-gate structure usually includes a semiconductor layer having a semiconductor property, a source electrode and a drain electrode formed so as to be in contact with and opposed to the semiconductor layer, and on the semiconductor layer. And a gate electrode formed on the gate insulating layer. On the other hand, a thin film transistor having a bottom gate type structure is usually a gate electrode, a gate insulating layer formed so as to cover the gate electrode, and a semiconductor layer formed on the gate insulating layer and functioning as a semiconductor. And a source electrode and a drain electrode formed to be in contact with the semiconductor layer and to face each other.

  In the present invention, the plurality of transistor portions are configured to be electrically connected to the sensor portion. Normally, however, the gate electrode constituting each transistor portion is connected to the detection electrode of the sensor portion. It is formed so that.

  In the present invention, a transistor portion comprising a thin film transistor having either the bottom gate structure or the top gate structure can be preferably used. Are preferably used. By forming the transistor portion used in the present invention from a thin film transistor portion having a bottom-gate structure, a part of the components of the transistor portion and a portion of the components of the sensor portion can be integrally formed. This is because the transistor type sensor that can be easily manufactured by a simple process can be easily obtained.

  Hereinafter, a transistor portion including a thin film transistor having a bottom gate structure will be described in detail. Note that a generally known thin film transistor can be used for a transistor portion including a thin film transistor having a top-gate structure.

  As described above, a transistor portion formed of a thin film transistor having a bottom-gate structure usually has a gate electrode, a gate insulating layer formed so as to cover the gate electrode, and a semiconductor formed on the gate insulating layer. And a semiconductor layer having such a function, and a source electrode and a drain electrode formed so as to be in contact with the semiconductor layer and to face each other.

(1) Gate electrode First, the gate electrode will be described. The gate electrode used in the present invention is not particularly limited as long as it has a function as an electrode. As such a gate electrode, for example, a transparent electrode such as ITO can be used in addition to a general metal material such as Al. The thickness of the gate electrode used in the present invention is usually preferably in the range of 50 nm to 500 nm.

(2) Gate Insulating Layer Next, the gate insulating layer will be described. The gate insulating layer used in the present invention is formed on the above-described gate electrode and has a function of insulating the gate electrode from other components used in the transistor portion. Therefore, the gate insulating layer used in the present invention is not particularly limited as long as it has a desired insulating property. Examples of such a gate insulating layer include those made of silicon oxide such as silicon oxide (SiO ₂ ), silicon nitride (SiN _x ), silicon nitride oxide (SiO _x N _y ), or silicon nitride. be able to. The thickness of the gate insulating layer used in the present invention is usually preferably in the range of 50 nm to 1 μm.

The gate insulating layer used in the present invention may be formed integrally with the ion sensitive film of the sensor unit. That is, as described above, since the gate insulating layer is made of an insulating material, and the ion sensitive film is also made of an insulating material, the insulating material used as the ion sensitive film is In some cases, the gate insulating layer may be used. Therefore, the gate insulating layer and the ion sensitive film can be integrally formed by selecting the type of insulating material. Since the configuration of the transistor type sensor of the present invention can be further simplified because the gate insulating layer and the ion sensitive film are integrally formed, a transistor type sensor that can be manufactured in a simpler process is provided. There is an advantage that it can be provided. Here, the details of the aspect in which the gate insulating layer and the ion sensitive film are integrally formed will be described in detail in the section of “4. Configuration of transistor type sensor” described later.
The term “integrally” means that the gate insulating layer and the detection electrode are formed as a single member having both functions.

When the gate insulating layer is formed integrally with the ion sensitive film, examples of the insulating material used for the gate insulating layer / ion sensitive film include SiO ₂ , Si ₃ N ₄ , Ta ₂ O ₅ , and Al _2. O ₃ etc. can be mentioned.

(3) Semiconductor layer Next, the semiconductor layer will be described. The semiconductor layer used in the present invention is formed on the gate insulating layer and exhibits semiconductor characteristics. The semiconductor layer used in the present invention is not particularly limited as long as it is made of a material having a function as a semiconductor.
Here, in a transistor type sensor having a laminated structure used for a conventional biosensor or the like, in order to visually observe the sample on the ion sensitive film of the sensor portion with transmitted light, the semiconductor layer has transparency There was a restriction that must be used. However, in the present invention, since the transistor portion and the sensor portion are arranged so as to be arranged in parallel on the same surface on the base material, visual observation is performed regardless of the type of semiconductor layer used in the transistor portion. There is an advantage that you can. In other words, the transistor-type sensor of the present invention has an advantage that there is no restriction on the material used for the semiconductor layer regardless of its application.

Thus, since there is no restriction | limiting in particular regarding the material used for the semiconductor layer in this invention, the material used for a semiconductor layer may have transparency, or may be opaque. As a material having transparency, for example, amorphous oxide mainly containing InMZnO (M is at least one of gallium (Ga), aluminum (Al), and iron (Fe)) can be given. In this case, an InGaZnO-based amorphous oxide in which M is Ga is particularly preferable. Further, when this InGaZnO-based amorphous oxide is used, it may be added Al, Fe, Sn or the like as a constituent element, if necessary. As the material having transparency, an oxide semiconductor containing zinc oxide (ZnO) as a main component can also be used. In addition to the intrinsic zinc oxide, the ZnO-based material may include p-type dopants such as lithium (Li), sodium (Na), nitrogen (N), and carbon (C), if necessary. Added zinc oxide doped with n-type dopants such as boron (B), aluminum (Al), gallium (Ga), indium (In) and zinc oxide doped with magnesium (Mg), beryllium (Be), etc. It may be a thing. Furthermore, as the material having transparency, a material such as indium oxide added with tin (indium tin oxide: ITO), indium zinc oxide (IZO), or magnesium oxide (MgO) can be used.
On the other hand, examples of the material having no transparency include amorphous silicon, polysilicon, organic semiconductor, and the like.

  The thickness of the semiconductor layer used in the present invention is not particularly limited as long as desired semiconductor characteristics can be realized according to the type of constituent material, etc., but is usually in the range of 5 nm to 100 nm. The

(4) Source and drain electrodes Next, the source and drain electrodes will be described. The source electrode and the drain electrode used in the present invention are formed so as to be in contact with the semiconductor layer and opposed to each other. The source electrode and drain electrode used in the present invention may have transparency or may not have transparency. Examples of the transparent source electrode and drain electrode include those made of indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO ₂ ), and the like. Moreover, as a source electrode and a drain electrode which do not have transparency, what consists of Ti, Mo, Cr, W etc. can be mentioned, for example. The thicknesses of the source electrode and the drain electrode used in the present invention are not particularly limited, but are usually preferably in the range of 20 nm to 200 nm.

(5) Transistor portion Even when the transistor portion used in the present invention is formed of a thin film transistor having a bottom-gate structure, the transistor portion may have another configuration other than the above as necessary. The other configuration is not particularly limited as long as the function of the transistor portion is not impaired, and a configuration having a desired function can be appropriately selected and used. As such another configuration, as a material suitably used in the present invention, for example, a passivation layer formed on the uppermost portion of the transistor portion can be cited. By using the passivation layer, there is an advantage that deterioration of the transistor portion can be prevented during the passage.

Examples of the passivation layer used in the present invention include those composed of SiO ₂ , Si ₃ N ₄ , Ta ₂ O ₅ , and Al ₂ O ₃ . The thickness of the passivation layer used in the present invention is not particularly limited, but is usually in the range of 50 nm to 1 μm.

As an aspect in which the passivation layer is formed in the transistor part, an aspect in which each transistor part is independently formed, or an aspect in which it is formed integrally with some of the components of the sensor part described above. Can be mentioned. The passivation layer in the present invention may be formed in any of these aspects, but is preferably formed integrally with some of the components of the sensor unit, and in particular, the ions of the sensor unit. It is preferable that it is the aspect formed integrally with the sensitive film | membrane. Since the passivation layer is formed in such a manner, the configuration of the transistor type sensor of the present invention can be further simplified, and therefore a transistor type sensor that can be manufactured by a simpler process is provided. Because you can.
Note that the term “integrally” means that the passivation layer and the ion-sensitive film are formed as a single member having both functions.

Here, when the passivation layer is formed integrally with the ion-sensitive film of the sensor unit, the passivation layer is required to be made of a material that also functions as an ion-sensitive film. However, as such a passivation layer, Examples thereof include those composed of SiO ₂ , Si ₃ N ₄ , Ta ₂ O ₅ , and Al ₂ O ₃ .

  The aspect in which the passivation layer is formed integrally with the ion sensitive film of the sensor part will be described in detail in the section of “4. Configuration of transistor type sensor” described later.

3. Next, the substrate used in the present invention will be described. The base material used in the present invention is not particularly limited as long as it can support the above-described transistor portion and sensor portion. Specific examples of such a base material include inorganic materials such as glass, plastics such as PEN or PET (polyester resin, polyethylene resin, polypropylene resin, ABS resin, nylon, acrylic resin, fluororesin, and polycarbonate resin. , Polyurethane resin, methylpentene resin, phenol resin, melamine resin, epoxy resin, vinyl chloride resin). In addition, the shape of the substrate used in the present invention is not limited, for example, flat shapes such as flat plates, flat membranes, films, porous membranes, cylinders, stamps, multiwell plates, microchannels, etc. These three-dimensional shapes are mentioned. When using a film, the thickness is not particularly limited, but is usually in the range of 1 μm to 1 mm.

  In addition, the base material used for this invention may have transparency, or may be opaque. However, when evaluating not only the voltage change but also the shape change of the sample in the sensor section according to the application of the transistor type sensor of the present invention, it is necessary to use the substrate having transparency as well. .

4). Next, the configuration of the transistor type sensor of the present invention will be described. The transistor type sensor of the present invention has structural features in at least the following two points.
First, the transistor type sensor of the present invention has a feature that a plurality of transistor portions and a sensor portion are arranged in parallel on the same surface of the substrate. By having such characteristics, the transistor type sensor of the present invention has less restrictions on the area where the ion sensitive film is formed in the sensor section, and can form the ion sensitive film over a wide area, and the ion sensitive film. When a sample to be measured is applied on top, there is an effect that there is no problem that the function of the transistor portion deteriorates due to the sample. Here, in the present invention, the sensor part and the plurality of transistor parts are arranged on the base material. However, in the present invention, the sensor part and the plurality of transistor parts are all on the same surface of the base material. It has been formed.
Second, the transistor type sensor of the present invention has a feature that a plurality of transistor portions are used, and the plurality of transistor portions are electrically connected to a single sensor portion. By having such characteristics, the transistor type sensor of the present invention can obtain normal value data by other transistor units even if a plurality of transistor units do not operate or malfunction. In addition, since it is possible to compare and examine data acquired by a plurality of transistor portions, an abnormal value can be easily distinguished, and accurate evaluation is performed by eliminating this abnormal value. There is an effect that it becomes possible. Furthermore, since data acquisition by a plurality of transistor units is possible, for example, the measurement data obtained in each transistor unit can be statistically processed to perform highly accurate evaluation.

  In the present invention, as a mode in which a plurality of transistor parts are electrically connected to a single sensor part, at least two or more transistor parts are electrically connected to a single sensor part. There is no particular limitation as long as it is an embodiment. If at least two or more transistor parts are electrically connected, even if some of the transistor parts do not operate or malfunction, the other transistor parts acquire normal value data. It is because it can be performed. However, in the present invention, it is preferable that three or more transistor portions are electrically connected to a single sensor portion from the viewpoint of enabling measurement with higher accuracy. In order to perform measurement with high accuracy, it can be said that it is desirable to obtain normal data by a plurality of transistor portions and perform statistical processing on the data. However, if three or more transistor portions are used, one of them is used. This is because even if one of them is abnormal, a highly accurate measurement value can be obtained by performing averaging processing or the like on normal data acquired by the remaining two transistor portions. Here, when three or more transistor portions are electrically connected to a single sensor portion, the upper limit value of the number of transistor portions is not particularly limited, and is suitable for the use of the transistor type sensor of the present invention. It can be determined accordingly.

  In the present invention, the mode in which the sensor unit and the plurality of transistor units are arranged on the base material is not particularly limited as long as the plurality of transistor units can be electrically connected to the single sensor unit. Although not intended, it is preferable that a plurality of transistors be arranged at equal intervals around a single sensor unit. As such an aspect, for example, when the sensor part is circular, the aspect in which the transistor parts are arranged at equal angles can be cited, and when the sensor part is square, An example in which the same number of transistor portions are arranged on the sides and the intervals of the transistor portions on each side are uniform can be given. Furthermore, an aspect in which one transistor portion is arranged at the center of each side of the polygonal sensor portion can be given.

  When the transistor portion used in the present invention includes the above-described thin film transistor having the bottom-gate structure, the transistor type sensor of the present invention is used for some components used in the transistor portion and the sensor portion. This makes it easy to form a part of the components as a unit. Then, by forming a part of the constituent elements used in the transistor part and a part of the constituent elements used in the sensor part as one body, the structure of the transistor type sensor of the present invention is simplified, and the process is simplified. There is an advantage that it can be manufactured. Such an advantage is also based on the fact that the sensor portion and the transistor portion are formed on the same surface of the substrate in the present invention.

  In the transistor-type sensor of the present invention, as an aspect in which some components used in the transistor portion and some components used in the sensor portion are integrally formed, for example, A mode in which the gate electrode and the detection electrode of the sensor unit are integrally formed; (b) a mode in which the gate insulating layer of the transistor unit and the ion sensitive film of the sensor unit are formed integrally; ) A mode in which the passivation layer of the transistor part and the ion sensitive film of the sensor part are integrally formed can be mentioned. Further, in the above aspect (c), an aspect in which the gate insulating layer of the transistor part and the insulating layer of the sensor part are integrally formed can be exemplified. In addition, the above aspect (a) can be employed in combination with the above aspect (a) or (c). Here, the above aspect (a) has the advantage that the electrical connection reliability is improved in addition to the advantage that the structure of the transistor-type sensor is simplified and can be manufactured by a simple process.

  Each aspect mentioned above is demonstrated referring a figure. FIG. 2 is a schematic cross-sectional view showing an example in which the gate electrode of the transistor portion and the detection electrode of the sensor portion are integrally formed in the transistor type sensor of the present invention. As illustrated in FIG. 2, in the transistor type sensor 1 of the present invention, the gate electrode 21 of the transistor unit 20 and the detection electrode 31 of the sensor unit 30 may be integrally formed.

  FIG. 3 is a schematic cross-sectional view showing an example of a mode in which the gate insulating layer of the transistor part and the ion sensitive film of the sensor part are integrally formed in the transistor type sensor of the present invention. As illustrated in FIG. 3, in the transistor type sensor 1 of the present invention, the transistor part 20 gate insulating layer 22 and the ion sensitive film 32 of the sensor part may be integrally formed. In FIG. 3, the gate electrode 21 of the transistor unit 20 and the detection electrode 31 of the sensor unit 30 are integrally formed.

FIG. 4 is a schematic cross-sectional view showing an example of a mode in which the passivation layer of the transistor part and the ion sensitive film of the sensor part are integrally formed in the transistor type sensor of the present invention. Here, FIG. 4A shows a representative example in which the passivation layer of the transistor portion and the ion sensitive film of the sensor portion are integrally formed, and FIG. 4B further shows the transistor portion. An example in which the gate insulating layer and the insulating layer of the sensor portion are integrally formed is shown. As shown in FIG. 4 (a), in the transistor type sensor 1 of the present invention, the passivation layer 26 of the transistor unit 20 and the ion sensitive film 32 of the sensor unit 30 may be integrally formed. Furthermore, as illustrated in FIG. 4B, the gate insulating layer 22 of the transistor unit 20 and the insulating layer 33 of the sensor unit 30 may be integrally formed.
In FIG. 4, the gate electrode 21 of the transistor unit 20 and the detection electrode 31 of the sensor unit 30 are integrally formed.

5. Applications of the transistor type sensor The transistor type sensor of the present invention applies a sample to the ion sensitive film of the sensor unit while applying a constant voltage between the source electrode and the drain electrode of the transistor unit, and inserts the sample into the sample. When a variable voltage (reference voltage) is applied to the sample via the reference electrode, the channel region formed in the semiconductor layer is changed according to the change in potential (hereinafter also referred to as “membrane potential”) generated in the ion sensitive film. Change, and a change in drain current can be detected. As a result, it is possible to specify the type of sample included in the sample by comparing the change in drain current based on the reference voltage, that is, the current-voltage characteristic as a transistor, with the current-voltage characteristic in a standard sample measured in advance. It can be done.

  Moreover, the transistor type sensor of this invention can also perform the form observation on an ion sensitive film | membrane by using what has transparency as said base material, a detection electrode, and an ion sensitive film | membrane. That is, the sample provided on the ion-sensitive film can be observed with a microscope or other optical observation equipment from the substrate side by irradiating light from above and using the transmitted light. In addition to bright field observation, a phase contrast microscope, a differential interference microscope, or the like can be used as necessary.

  Since the transistor-type sensor of the present invention operates in this way, it can be used for the evaluation of all materials. In particular, biological-related substances such as cells, DNA, sugar chains, and proteins can be used. It can be suitably used as a biosensor to be evaluated.

6). Next, a method for manufacturing a transistor type sensor according to the present invention will be described. The transistor type sensor of the present invention can be formed by the following method, for example. That is, first, after forming a metal film on a substrate by sputtering or the like, the metal film is patterned by photolithography or the like to form a gate electrode / detecting electrode. At this time, the metal film is patterned so that a plurality of gate electrodes are electrically connected to a single detection electrode. Next, a gate insulating layer / ion sensitive film is formed on the entire surface of the substrate so as to cover the gate electrode / detection electrode. Next, a semiconductor film is formed on the entire surface of the substrate so as to cover the gate insulating film / ion-sensitive film by sputtering or the like, and the semiconductor film is patterned by photolithography or the like to form a semiconductor layer. To do. Next, a metal film is formed on the entire surface of the semiconductor layer by sputtering or the like, and the metal film is patterned by photolithography or the like to form a source electrode and a drain electrode. According to such a method, it is possible to manufacture a transistor type sensor in which the gate insulating layer of the transistor part and the ion sensitive film of the sensor part are integrally formed.

B. Measurement Method Next, the measurement method of the present invention will be described. As described above, the measurement method of the present invention is a measurement method using the transistor type sensor according to the present invention, and includes a data acquisition step of acquiring measurement data by a plurality of the transistor units, and the data acquisition step. And a data processing step for processing the acquired measurement data.

  According to the present invention, in the above data acquisition step, measurement data is acquired from a plurality of transistor units included in the transistor type sensor of the present invention, so that it does not operate on a part of the plurality of transistor units, or operates poorly. Even if included, normal value data can be obtained from other transistor portions. Further, since it becomes possible to compare and examine data acquired by a plurality of transistor portions, an abnormal value can be easily determined, and accurate evaluation can be performed by eliminating this abnormal value. Furthermore, by processing the measurement data acquired from the plurality of transistor portions in the data processing step, a highly accurate measurement result can be obtained.

The measurement method of the present invention includes at least the data acquisition step and the data processing step, and may include other steps as necessary.
Hereafter, each process used for this invention is demonstrated in order.

1. Data Acquisition Step First, the data acquisition step used in the present invention will be described. This step is a step of using the transistor-type sensor according to the present invention to obtain measurement data with a plurality of transistor portions included in the transistor-type sensor. In this step, the method for acquiring measurement data with a plurality of transistor portions can be appropriately determined according to the measurement target, and is not particularly limited. Examples of such a method include a method of simultaneously obtaining measurement data with a plurality of transistor portions, a method of sequentially obtaining measurement data with a plurality of transistors, and the like.

2. Data Processing Step Next, the data processing step used in the present invention will be described. This step is a step of obtaining a measurement result by processing a plurality of measurement data acquired through the transistor unit in the data acquisition step.

  In this step, the method for processing the measurement data is not particularly limited as long as a desired measurement result can be obtained according to the purpose of the measurement method of the present invention. Here, it is desirable that the number of transistor portions used in the present invention be large, but there are cases where many transistor portions cannot be arranged and connected due to layout restrictions. Therefore, it is preferable to select and use an appropriate data processing method according to the number of transistor portions. For example, when two transistor portions are used, a data processing method may include a method of calculating an average value of measurement data of each transistor portion. In addition, when three transistor parts are used, the average value of the three measurement data is taken, or it is extremely larger than the other two values depending on the purpose. Take the average of the two. In this case, as a criterion for determining the measurement data to be excluded, for example, an abnormal value may be used when the average value is 15% or more greater than or smaller than all average values. This value of 15% can be set arbitrarily depending on the reliability of the process. When set in this way, the transistor can be played in the case where no current is flowing due to a problem such as disconnection of the wiring. When four or more transistor portions are used, basically the same data processing method as when three transistor portions are used can be employed.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  Hereinafter, the present invention will be specifically described with reference to examples.

In this example, a transistor type sensor having a bottom gate / top contact structure was formed on a glass substrate. First, a gate electrode film having a thickness of 100 nm was formed on the entire surface by sputtering, then a resist pattern was formed by photolithography and then etched, and the gate electrode film was patterned into a predetermined pattern to form a gate electrode. Next, silicon oxide having a thickness of 300 nm was formed as a gate insulating film on the entire surface so as to cover the gate electrode. This gate insulating film is formed using an RF magnetron sputtering apparatus with an input power of 2.0 kW (= 6 W / cm ² ), a pressure of 0.3 Pa, and a mixed gas of O ₂ and Ar using an 8-inch SiO ₂ target. did. Thereafter, contact holes were formed by dry etching.

Next, an InGaZnO-based IGZO semiconductor film (InGaZnO ₄ ) with an In: Ga: Zn ratio of 1: 1: 1 was formed on the entire surface so as to cover the gate insulating film so as to have a thickness of 25 nm. The IGZO semiconductor film is a 4-inch InGaZnO (In: Ga: Zn = 1: 1: 1) target using an RF magnetron sputtering apparatus under conditions of room temperature (25 ° C.) and Ar: O ₂ of 30:50. Formed using. Next, after forming a resist pattern on the IGZO semiconductor film by photolithography, wet etching was performed with an oxalic acid solution, and the IGZO semiconductor film was patterned to form an IGZO semiconductor film having a predetermined pattern.

  Next, after forming a 200 nm-thick titanium film on the entire surface of the IGZO semiconductor film by sputtering to form a source electrode and a drain electrode, a resist pattern is formed by photolithography, and then a mixed solution of hydrogen peroxide and ammonia Wet etching was performed, and the titanium film was patterned into a predetermined pattern to form a source electrode and a drain electrode. At this time, the source electrode and the drain electrode were formed on the IGZO semiconductor film so as to have a pattern apart from other than just above the central portion of the IGZO semiconductor film.

  Next, 100 nm thick silicon oxide was formed as a passivation layer by RF magnetron sputtering so as to cover all of the source electrode, drain electrode, and IGZO semiconductor film, and contact holes were formed by dry etching. Thereafter, heat treatment at 300 ° C. for 60 minutes was performed in an air atmosphere. Thus, a transistor type sensor was produced. As shown in FIG. 8, the transistor type sensor manufactured in this example had a configuration in which two transistor units 20 were connected to one side of a square sensor unit 30.

  For evaluation, a glass tube was adhered on the surface of the sensor unit as shown in FIG. 5, and an alkaline solution having a pH of 10 was put into the tube. FIG. 6 shows the transfer characteristics of the transistor before and after the addition of the solution. FIG. 6 shows an example in which the charging phenomenon generated in the sensor unit by introducing the solution is transmitted through the gate electrode running in the lateral direction and observed as a shift in the threshold voltage of the transistor.

  Next, an averaging process when the shift amount of the above evaluation is measured at 6 points will be described. For example, when the results as shown in the table of FIG. 7 are obtained, all the average values are 1.27V. For example, ± 15% of 1.27V is changed from 1.08V to 1.46V. From this reference, it can be determined that the transistors other than No. 4 are normal and the No. 4 transistor is abnormal. If the average value is taken once again except for No. 4, it becomes 1.51 V, and this average value can be used to determine the shift amount of the ion sensitive region. As shown in FIG. 8, the transistor type sensor manufactured in this example has eight transistor parts connected to one sensor part, and one of them is a gate electrode. Since another foreign matter on the transistor was confirmed, six points were excluded from visual inspection. However, it is possible to arbitrarily exclude from the measurement points by visual inspection.

DESCRIPTION OF SYMBOLS 1 ... Transistor type sensor 10 ... Base material 20 ... Transistor part 21 ... Gate electrode 22 ... Gate insulating layer 23 ... Semiconductor layer 24 ... Source electrode 25 ... Drain electrode 26 ... Passivation layer 30 ... Sensor part 31 ... Detection electrode 32 ... Ion Sensitive film 33 ... Insulating layer

Claims (3)

A substrate;
A transistor portion having a function as a thin film transistor;
A sensor unit having a detection electrode and an ion-sensitive film formed on the detection electrode and made of an insulating material;
Have
The transistor part and the sensor part are arranged in parallel on the same surface of the substrate, and a plurality of the transistor parts are used, and a plurality of the transistor parts are used for a single sensor part. A transistor-type sensor, wherein the transistor portion is electrically connected.   2. The substrate according to claim 1, wherein the substrate has transparency, the detection electrode has transparency, and the ion-sensitive membrane has transparency. Transistor type sensor. A measurement method using the transistor type sensor according to claim 1 or 2,
A data acquisition step of acquiring measurement data with a plurality of the transistor portions;
A data processing step for processing the measurement data acquired in the data acquisition step;
A measurement method characterized by comprising:

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