JP2007178134A - Flexible substrate with ion sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible substrate with an ion sensor capable of reducing the manufacturing cost. <P>SOLUTION: The flexible substrate 1 with the ion sensor comprises a flexible substrate 2 having flexibility, and a plurality of thin-film transistors 3 that are arranged in a matrix shape on this flexible substrate 2 and serve as sensors for detecting ion concentration. The flexible substrate 2 has a reference electrode. Each thin-film transistor 3 comprises a source electrode 4 and drain electrode 5 formed so that a gate region is sandwiched between them on the flexible substrate 2, an organic semiconductor layer 6 made of organic semiconductor material stacked on the gate region of the flexible substrate 2, a gate insulating film 7 stacked on the flexible substrate 2 while covering the source electrode 4, drain electrode 5 and organic semiconductor layer 6, and an ion sensitive film 8 stacked on the gate insulating film 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flexible substrate with an ion sensor used in a solution analyzer for analyzing ion concentration in a solution.

  In general, an ion sensitive field effect transistor (ISFET) is used as a sensor for detecting an ion concentration in a solution analyzer. In this ISFET, when the solution comes into contact with the ion sensitive film on the gate of the ISFET, an interface potential is generated according to the ion concentration in the solution, and this can be used to detect the ion concentration in the solution.

  In recent years, on a flexible flexible substrate so that an ISFET can be attached along the curved inner wall surface of a solution tank included in the solution analyzer, or an ISFET can be attached to the probe of the solution analyzer. There is provided a flexible substrate with an ion sensor provided with a thin film ISFET (hereinafter sometimes referred to as “thin film transistor”) (see, for example, Patent Document 1).

  The thin film transistor in the flexible substrate with an ion sensor includes a source electrode and a drain electrode formed on the flexible substrate so as to sandwich the gate region, a semiconductor layer stacked on the gate region of the flexible substrate, a source electrode, A gate insulating film laminated on the flexible substrate while covering the drain electrode and the semiconductor layer, and an ion sensitive film laminated on the gate insulating film, the ion sensitive film being in contact with the solution. Here, the semiconductor layer is made of an inorganic semiconductor material such as silicon, and a portion stacked on the gate insulating film between the source electrode and the drain electrode functions as a channel layer.

In addition, the flexible substrate here includes a reference electrode that is in contact with the solution. The flexible substrate with an ion sensor is configured to include such a thin film transistor, and as a whole, can be bent to some extent.
JP 2004-144705 A

  However, in the above-described conventional flexible substrate with an ion sensor, since the semiconductor layer that is a constituent element of the thin film transistor is made of an inorganic semiconductor material, the manufacturing process requires a high-temperature process, and a large clean room, vacuum device, etc. are available. Large scale equipment is also required. Therefore, it is difficult to reduce the manufacturing cost.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a flexible substrate with an ion sensor capable of reducing the manufacturing cost.

  In order to achieve the above object, a flexible substrate with an ion sensor according to the present invention comprises a flexible substrate having flexibility and a thin film transistor disposed on the flexible substrate and serving as a sensor for detecting ion concentration. The flexible substrate includes a reference electrode, and the thin film transistor is stacked on the gate region of the flexible substrate, the source electrode and the drain electrode formed so as to sandwich the gate region between the flexible substrate, An inorganic semiconductor layer made of an inorganic semiconductor material, a gate insulating film laminated on the flexible substrate while covering the source electrode, the drain electrode and the inorganic semiconductor layer, and an ion sensitive film laminated on the gate insulating film In the flexible substrate with an ion sensor including To. A plurality of the thin film transistors are arranged in a matrix on a flexible substrate, and each of the thin film transistors includes an organic semiconductor layer made of an organic semiconductor material instead of the inorganic semiconductor layer, and the organic semiconductor layer constituting the organic semiconductor layer The semiconductor material is pentacene, the material of the source electrode and the drain electrode is gold, and the material of the flexible substrate is a polymer resin.

  In such a configuration, since the semiconductor layer, which is a constituent element of the thin film transistor, is made of an organic semiconductor material, by utilizing the features of the organic substance and by dissolving the organic substance in a solvent, the printing technology such as a rotary press or an inkjet is utilized. A circuit can be easily manufactured. In particular, a thin film transistor can be manufactured by a low-temperature process.

  In order to achieve the above object, a flexible substrate with an ion sensor according to the present invention is a flexible substrate having flexibility and a sensor for detecting ion concentration arranged in a matrix on the flexible substrate. A plurality of thin film transistors, wherein the flexible substrate includes a reference electrode, and each of the thin film transistors includes a source electrode and a drain electrode formed on the flexible substrate so as to sandwich a gate region between the thin film transistor and the flexible substrate. An organic semiconductor layer made of an organic semiconductor material, stacked on the gate region, a gate insulating film stacked on the flexible substrate while covering the source electrode, the drain electrode, and the organic semiconductor layer, and the gate insulating film And an ion sensitive film laminated thereon.

  In such a configuration, since the semiconductor layer, which is a constituent element of the thin film transistor, is made of an organic semiconductor material, by utilizing the features of the organic substance and by dissolving the organic substance in a solvent, the printing technology such as a rotary press or an inkjet is utilized. A circuit can be easily manufactured. In particular, a thin film transistor can be manufactured by a low-temperature process.

  Here, the organic semiconductor material constituting the organic semiconductor layer is preferably pentacene. The material of the source electrode and the drain electrode is preferably gold. The material of the flexible substrate is preferably a polymer resin.

  According to the flexible substrate with an ion sensor of the present invention, the manufacturing cost can be reduced because it can be manufactured by a low-temperature process.

  Hereinafter, an embodiment of the flexible substrate with an ion sensor of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a flexible substrate with an ion sensor according to an embodiment of the present invention, and FIG. 2 is a sectional view of a thin film transistor portion of the flexible substrate with an ion sensor.

  As shown in FIG. 1, the flexible substrate 1 with an ion sensor of the present embodiment is roughly composed of a flexible substrate 2 having flexibility, and a plurality of thin film transistors 3 arranged in a matrix on the flexible substrate 2. Consists of. 1 shows an example in which the thin film transistors 3 are arranged in 3 rows × 4 columns.

  Here, examples of the material of the flexible substrate 2 include polymer resins such as polyethylene naphthalate (PEN), polyimide (PI), and polyethylene terephthalate (PET).

  Each thin film transistor 3 functions as a sensor for detecting the ion concentration. As shown in FIG. 2, the thin film transistor 3 is largely composed of a source electrode 4, a drain electrode 5, a semiconductor layer 6, and a gate. Insulating film 7 and ion sensitive film 8 are included. Both the source electrode 4 and the drain electrode 5 are formed on the flexible substrate 2, and are formed so as to open a gate region on the flexible substrate 2 and sandwich the gate region therebetween. Examples of the material of the source electrode 4 and the drain electrode 5 include metals such as gold and silver.

  The semiconductor layer 6 is stacked on the gate region between the source electrode 4 and the drain electrode 5 in the flexible substrate 2, and the gate insulating film 7 is flexible while covering the source electrode 4, the drain electrode 5, and the semiconductor layer 6. It is laminated on the substrate 2. Here, the semiconductor layer 6 is made of an organic semiconductor material, and a portion 6 a stacked on the gate insulating film 7 between the source electrode 4 and the drain electrode 5 functions as a channel layer. Examples of the organic semiconductor material include pentacene, copper nitrocyanine, oligothiophene, and polythiophene.

  In practice, self-assembled monolayers 4a and 5a made of organic materials with a thickness of 1 nm or less are provided between the source electrode 4 and the gate insulating film 7 and between the drain electrode 5 and the gate insulating film 7. It is preferable to interpose. In particular, electrons flow directly from the source electrode 4 to the chanel layer 9a, so that the electron mobility is improved, and as a result, the performance of the thin film transistor 3 is improved. The self-assembled monomolecular films 4a and 5a mentioned here are films utilizing the property that, when a predetermined treatment is performed, organic molecules adhere to one molecule by a chemical reaction.

  The ion sensitive film 8 is laminated on the gate insulating film 7, and the ion sensitive film 8 is in contact with the solution. The flexible substrate 2 here includes a reference electrode that is in contact with the solution, although not shown.

  In such a thin film transistor 3, it is possible to easily produce a circuit by utilizing a printing technique such as a rotary press or an ink jet by dissolving the organic substance in a solvent by utilizing the characteristics of the organic substance. However, since the semiconductor layer 6 which is a constituent element of the thin film transistor 3 is made of an organic semiconductor material, the flexible substrate 1 with an ion sensor, particularly the thin film transistor 3 can be manufactured by a low temperature process. Therefore, the manufacturing cost can be reduced.

  And since it is a low-temperature process, when the flexible substrate 2 is comprised with a polymer resin, the thin film transistor 3 has favorable compatibility with the flexible substrate 2. Therefore, the flexible substrate 1 with an ion sensor can allow flexible and flexible bending as a whole including the thin film transistor 3.

  Moreover, such a flexible substrate with an ion sensor 1 can be attached along a curved inner wall surface of a solution tank included in the solution analyzer, or can be attached to a probe of the solution analyzer. In the analysis of the solution, when the solution is in contact with the ion sensitive film 8 in each thin film transistor 3, an interface potential is generated between the ion sensitive film 8 and the channel layer 6a of the semiconductor layer 6 according to the ion concentration in the solution. As a result, a current corresponding to the ion concentration flows between the drain electrode 5 and the source electrode 4. And the ion concentration in a solution is detectable by detecting the electric current value. In addition, since a plurality of thin film transistors 3 are provided in a matrix, the individual thin film transistors 3 can detect the ion concentration in the solution in contact with each other, and can perform detection over a wide range with high detection accuracy. There is also an advantage that it can be obtained.

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention is useful for a flexible substrate with an ion sensor used in a solution analysis instrument.

It is a perspective view of the flexible substrate with an ion sensor which is one embodiment of the present invention. It is sectional drawing of the thin-film transistor part in the flexible substrate with an ion sensor which is one Embodiment of this invention.

Explanation of symbols

1 Flexible substrate with ion sensor 2 Flexible substrate 3 Thin film transistor 4 Source electrode 5 Drain electrode 6 Organic semiconductor layer 7 Gate insulating film 8 Ion sensitive film

Claims (5)

A flexible substrate having flexibility, and a thin film transistor disposed on the flexible substrate and serving as a sensor for detecting ion concentration,
The flexible substrate includes a reference electrode;
The thin film transistor includes a source electrode and a drain electrode formed so as to sandwich a gate region on the flexible substrate, an inorganic semiconductor layer made of an inorganic semiconductor material laminated on the gate region of the flexible substrate, In a flexible substrate with an ion sensor, comprising: a gate insulating film stacked on the flexible substrate while covering the source electrode, the drain electrode, and the inorganic semiconductor layer; and an ion-sensitive film stacked on the gate insulating film. ,
A plurality of the thin film transistors are arranged in a matrix on a flexible substrate,
Each thin film transistor includes an organic semiconductor layer made of an organic semiconductor material instead of the inorganic semiconductor layer,
The organic semiconductor material constituting the organic semiconductor layer is pentacene,
The material of the source electrode and the drain electrode is gold,
A flexible substrate with an ion sensor, wherein the material of the flexible substrate is a polymer resin. A flexible substrate having flexibility, and a plurality of thin film transistors arranged in a matrix on the flexible substrate and serving as sensors for detecting ion concentration,
The flexible substrate includes a reference electrode;
Each of the thin film transistors includes a source electrode and a drain electrode formed so as to sandwich a gate region on the flexible substrate, and an organic semiconductor layer made of an organic semiconductor material stacked on the gate region of the flexible substrate, And a gate insulating film laminated on the flexible substrate while covering the source electrode, the drain electrode and the organic semiconductor layer, and an ion sensitive film laminated on the gate insulating film. Flexible substrate with ion sensor.   The flexible substrate with an ion sensor according to claim 2, wherein the organic semiconductor material constituting the organic semiconductor layer is pentacene.   4. The flexible substrate with an ion sensor according to claim 2, wherein a material of the source electrode and the drain electrode is gold.   5. The flexible substrate with an ion sensor according to claim 2, wherein the material of the flexible substrate is a polymer resin.

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