JP2004006806A - Organic semiconductor element, rf modulation circuit and ic card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic semiconductor element in simple configuration having a pair of electrodes facing each other on a base material and an organic semiconductor layer between the pair of the electrodes. <P>SOLUTION: The organic semiconductor layer 3 is provided on the surface of a first electrode 2, and a first extraction electrode 6 is connected to the projected part of the first electrode 2 where the organic semiconductor layer 3 is not provided on the surface of the first electrode 2. On a part of the surface of the organic semiconductor layer 3, a second electrode 4 and a second extraction electrode 8 connected to the second electrode 4 are provided. At the protrusion of the organic semiconductor layer 3 where the second electrode is not provided, a third take-out electrode 7 connected to the organic semiconductor layer 3 is formed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an organic semiconductor element, an RF modulation circuit having the organic semiconductor element, and an IC card having the organic semiconductor element.
[0002]
[Prior art]
2. Description of the Related Art In recent years, electronic devices using organic semiconductor materials have been widely developed, and development of organic EL (Electro-Luminescence), organic TFT (Thin Film Transistor), organic semiconductor laser, and the like, which are light emitting elements, has been reported. I have. Among them, an organic TFT, which is a kind of an organic transistor, is regarded as a promising technology for forming an integrated circuit on a glass or plastic substrate at low cost.
[0003]
With respect to the structure of the organic TFT, Japanese Patent Application Laid-Open Nos. 08-228034, 09-232589, and 10-270712 disclose elements having a source and drain electrodes, a gate insulating film, and a gate electrode. .
[0004]
It has been pointed out that organic semiconductors have lower mobility than Si-based semiconductors and do not follow at high frequencies. In order to improve this point, mobility is improved by improving the crystallinity of the organic semiconductor (C. Dimitropoulos et al. Science Vol. 283 (1999) P. 822), and the gate length is extremely shortened ( JH Schon et.al. Nature Vol.413 (2001) P.713).
[0005]
[Problems to be solved by the invention]
However, there remains a problem of low cost, such as a need to go through complicated steps.
[0006]
An object of the present invention is to provide an organic semiconductor having a simple configuration.
[0007]
[Means for Solving the Problems]
Therefore, the present invention
Having a pair of electrodes facing each other on the substrate, and an organic semiconductor layer between the pair of electrodes,
A first extraction electrode connected to a first electrode of the pair of electrodes;
A second extraction electrode connected to a second electrode of the pair of electrodes;
An organic semiconductor device having a third extraction electrode connected to the organic semiconductor layer.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
One example of the organic semiconductor element of the present invention will be described below as an embodiment.
[0009]
The organic semiconductor element according to the embodiment of the present invention is an organic semiconductor element characterized in that each of a pair of electrodes and an organic semiconductor layer between the pair of electrodes individually have an extraction electrode.
[0010]
FIG. 1 is a schematic cross-sectional view showing a layer configuration of the organic semiconductor element of the present embodiment.
[0011]
1 is a substrate, 2 is a first electrode, 3 is an organic semiconductor layer, 4 is a second electrode, 5 is a protective layer, 6 is a first extraction electrode, 7 is a third extraction electrode, and 8 is a second extraction electrode. Electrode.
[0012]
A first electrode 2 is provided on a base material, an organic semiconductor layer 3 is provided thereon, and a second electrode 4 is provided on the organic semiconductor layer 3, that is, This configuration is a stacked configuration in which a pair of opposing electrodes (the first electrode 2 and the second electrode 4) and the organic semiconductor layer 4 are provided therebetween.
[0013]
The first, second, and third extraction electrodes 6, 8, and 7 are connected to the first electrode 2, the second electrode 4, and the organic semiconductor layer 3, respectively.
[0014]
As described above, an organic semiconductor element having a very simple configuration can be provided in this embodiment.
[0015]
Further, in the organic semiconductor element of the present embodiment, the organic semiconductor layer 3 is provided on a part of the surface of the first electrode 2 as illustrated. Further, no organic semiconductor layer is provided on other portions of the surface of the first electrode 2. Then, the first electrode 2 protruding from the organic semiconductor layer 3 is provided. With such a configuration, the first extraction electrode 6 can be connected to the first electrode 2 in the protruding first electrode portion.
[0016]
Further, in the organic semiconductor element of the present embodiment, the second electrode 4 is provided on a part of the surface of the organic semiconductor layer 3 as shown in the figure. Further, the second electrode 4 is not provided on other portions of the surface of the organic semiconductor layer 3. Then, the organic semiconductor layer 3 protruding from the second electrode 4 is provided. With this configuration, the third extraction electrode 7 can be connected to the organic semiconductor layer 3 in the protruding organic semiconductor layer.
[0017]
Further, in the organic semiconductor element of the present embodiment, the second extraction electrode 8 is connected to the second electrode 4. As described above, since the second electrode 4 protrudes from the organic semiconductor layer 3 and the organic semiconductor layer 3 protrudes from the first electrode 2, the first to third extraction electrodes 6, 7, and 8 are interconnected. Direction can be aligned in one direction.
[0018]
In the organic semiconductor element of the present embodiment, the protective layer 5 is disposed so as to cover the first electrode 2, the organic semiconductor layer 3, and the second electrode 4. The first to third extraction electrodes 6, 7, 8 are arranged so as to be extracted from the same side of the protective layer 5 (in this case, from one surface side).
[0019]
In the organic semiconductor element of the present embodiment, although not shown, the magnitude relationship of the surfaces where the respective layers are in contact with each other is that the surface of the second electrode <the surface of the organic semiconductor layer <the surface of the first electrode. Can be. That is, when the organic semiconductor element is viewed from above and below the paper surface, the organic semiconductor layer 3 is disposed inside the surface where the first electrode 2 contacts the organic semiconductor layer 3. That is, the outline of the organic semiconductor layer 3 is entirely surrounded by the protruding portion of the surface of the first electrode 2 on the surface where the first electrode 2 contacts the organic semiconductor layer 3. In addition, the second electrode 4 is disposed inside the surface where the organic semiconductor layer 3 is in contact with the second electrode 4. That is, the outline of the second electrode 4 is entirely surrounded by the protruding portion of the surface of the organic semiconductor layer on the surface where the organic semiconductor layer 3 is in contact with the second electrode 4. With this configuration, the second electrode 4 is surely arranged inside the surface of the organic semiconductor layer 3, and direct contact between the second electrode 4 and the first electrode can be prevented.
[0020]
The organic semiconductor element according to this embodiment may be a junction-type transistor. The third extraction electrode 7 connected to the organic semiconductor layer 3 can be used as a base electrode, one of the first and second extraction electrodes 6 and 8 can be used as an emitter electrode, and the other can be used as a collector electrode. In this case, as the collector electrode, the first extraction electrode 6 connected to the wide (large area) first electrode 2 is more preferable. Of course, the second extraction electrode 8 connected to the second electrode 4 may be used as the collector electrode. Optimal adjustment of the film thickness of the organic semiconductor layer 3 provided in a plane can be easily and accurately achieved by a film forming technique such as vacuum evaporation. In addition, a favorable amplification phenomenon can be obtained as a junction type transistor. For example, when a rectangular wave of 500 KHz is input, an amplification phenomenon with a gain of about several tens to one hundred can be recognized. Alternatively, a characteristic based on a good cutoff frequency (a characteristic capable of maintaining a sufficient gain at a high frequency) can be obtained (for example, a cutoff frequency of about 600 KHz can be measured), and the organic semiconductor of the present embodiment is used as a component of the RF modulation circuit An element can be provided.
[0021]
In the organic semiconductor element according to the present embodiment, the organic semiconductor layer 3 may be made of an organic compound such as pentacene. As the organic compound, for example, one having good orientation and good crystallinity may be used.
[0022]
In the organic semiconductor element according to this embodiment, the Fermi level of the first electrode and the second electrode may be between the conduction band level and the valence band level of the organic semiconductor layer.
[0023]
In the organic semiconductor element according to the present embodiment, the Fermi level of the first electrode and the Fermi level of the second electrode may be different from each other, for example, such that the Fermi level of the collector-side electrode is lower. By doing so, more emitter current can be obtained.
[0024]
In the organic semiconductor element according to the present embodiment, by setting the thickness of the organic semiconductor layer to 100 nm or less, the emitter current can be increased and the amplification factor can be increased.
[0025]
In the organic semiconductor element according to the present embodiment, the organic semiconductor layer may have p-type or n-type conductivity.
[0026]
In the organic semiconductor element according to the present embodiment, when the organic semiconductor layer is a p-type, for example, any one of Pt, Au, Ag, Pd, Ir, Ni, Te, Co, and Se is used as the third extraction electrode. Or an alloy containing the metal, or an oxide such as ITO (Zn, Sn oxide).
[0027]
In the organic semiconductor element according to the present embodiment, when the organic semiconductor layer is a p-type, the first electrode and the second electrode may be made of the same material or different materials. For example, a metal of any one of Ba, Ca, La, Li, Na, Sc, Sr, and Y, or an alloy containing the metal, for example, can be given.
[0028]
In the organic semiconductor element according to the present embodiment, when the organic semiconductor layer is n-type, for example, any one of Ba, Ca, La, Li, Na, Sc, Sr, and Y as a third extraction electrode, or For example, an alloy containing the metal can be given.
[0029]
In the organic semiconductor element according to the present embodiment, when the organic semiconductor layer is n-type, the first electrode and the second electrode may be made of the same material or different materials. For example, a metal of any of Pt, Au, Ag, Pd, Ir, Ni, Te, Co, and Se, or an alloy containing the metal, for example, can be used.
[0030]
The organic semiconductor element according to the present embodiment uses an insulating member as a base material, but may use a polyimide resin, for example. In the organic semiconductor element according to the present embodiment, a material that does not bend may be used as a base material, or a flexible material may be used.
[0031]
In the organic semiconductor element according to the present embodiment, an insulating member is used as a protective layer, and for example, silicon oxide can be used.
[0032]
In the organic semiconductor element according to the present embodiment, the first electrode and the organic semiconductor layer, or the organic semiconductor layer and the second electrode are provided in direct contact with each other. The organic semiconductor layer and the organic semiconductor layer need only be substantially electrically connected to each other, and another extremely thin layer may be provided between the two. Alternatively, at least one of them may have a multilayer structure. The same applies to the organic semiconductor layer and the second electrode as long as they are substantially electrically connected to each other, and another extremely thin layer may be provided between them. Alternatively, at least one of them may have a multilayer structure.
[0033]
In the organic semiconductor element according to the present embodiment, a first electrode is formed on a base material (Step 1), an organic semiconductor film is formed on the first electrode (Step 2), and an organic semiconductor film is formed on the organic semiconductor layer. A second electrode is formed (Step 3), and a protective layer is formed so as to cover them (Step 4), and an extraction electrode can be connected to each of the first electrode, the organic semiconductor layer, and the second electrode. It can be obtained by digging the protective layer up to (Step 5) and forming extraction electrodes at each of the dug locations (contact holes) (Step 6).
[0034]
In the organic semiconductor element according to the present embodiment, the organic semiconductor layer can be obtained by the above-described vacuum deposition, but may be obtained by a printing technique (for example, transfer or ink jet technique).
[0035]
In the organic semiconductor element according to the present embodiment, the first or second electrode may be obtained by using a vacuum film forming technique such as DC sputtering.
[0036]
In the organic semiconductor element according to the present embodiment, the protective film may be obtained by using a vacuum film forming technique such as plasma CVD.
[0037]
The organic semiconductor element according to the present embodiment may have a dry etching technique for digging only a necessary portion of a trench hole using a resist.
[0038]
In the organic semiconductor element according to the present embodiment, the extraction electrode may be obtained by using a metal mask technique.
[0039]
【Example】
(Example 1)
Example 1 of the present invention describes a method for manufacturing an organic semiconductor element which is a transistor element.
[0040]
2 to 7 are cross-sectional views of only the transistor portion.
[0041]
As shown in FIG. 2, first, a first conductor layer 10 made of lanthanum is formed on the surface of an insulator substrate 9 made of a polyimide resin by a DC sputtering method through a metal mask (not shown).
[0042]
Next, as shown in FIG. 3, an organic semiconductor layer 11 made of pentacene is formed by vacuum evaporation through a metal mask (not shown). At this time, the thickness of the organic semiconductor layer is 20 nm. Further, as shown in FIG. 4, a second conductor layer 12 made of lanthanum is formed by a DC sputtering method. The thickness of each of the first conductor layer and the second conductor layer is about 200 nm.
[0043]
Next, as shown in FIG. 5, a protective insulating layer 13 made of silicon oxide was formed by plasma CVD. The thickness is about 500 nm. A resist is applied to the surface and exposed by a photolithography process, and then dry etching using methane tetrafluoride as an etchant is performed to form a contact hole. As a result, an opening can be formed as shown in FIG.
[0044]
Next, a collector electrode 14, a base electrode 15, and an emitter electrode 16 made of platinum are formed through a metal mask (not shown) to obtain a transistor element as shown in FIG.
[0045]
A power supply is connected to this transistor element as shown in FIG. 8 to form a common emitter circuit. This transistor element can obtain good transistor characteristics with a gain of about 100 as shown in FIG.
[0046]
The cut-off frequency of this transistor element was measured to be about 600 kHz from the frequency dependence of the gain in an emitter-installed circuit.
[0047]
When a 500 kHz rectangular wave is input to the base electrode of the prototype device, a collector current larger than the base current can be obtained, and the transistor amplification phenomenon can be observed.
[0048]
(Example 2)
In this embodiment, an organic semiconductor element, which is the transistor element described in the embodiment, is used for an IC card.
[0049]
FIG. 10 is a diagram schematically illustrating each functional area in the plane of the IC card 20 according to the second embodiment.
[0050]
17 is a magnetic recording area, 18 is a ROM array area, 19 is a fuse array area, and 21 is a data input / output terminal I / O.
[0051]
The ROM array area 18 is an area in which, for example, a serial number or the like can be written at the time of card emission. This area is obtained by on-demand printing, but this area can be formed by inkjet technology.
[0052]
The fuse array region 19 is a region where a fuse can be blown for each use frequency, and is a region for the purpose of strengthening security.
[0053]
Note that the magnetic recording area 17 is an area provided for being used together for stable retention of recorded information.
[0054]
As described above, each area is provided on the entire surface of the IC card, and a plurality of transistor elements according to the present embodiment are provided in the switching element, the amplifier circuit, the shift register circuit, and the like in each area.
[0055]
Further, in the transistor element of this embodiment, all the base-emitter collector electrodes can be taken out of the element from one side, so that even in such a plane, the base-emitter collector electrodes, which are the lead electrodes, are on the one side of the IC card. Can all be taken out. Therefore, when connecting to each other's transistor element or connecting to a semiconductor element in another area, wiring connection can be made on one side of the IC card.
[0056]
In order to construct a non-contact IC card, a transistor having a sufficient gain in an RF band (1 MHz or more) is required, and this can be achieved by the organic semiconductor device of this embodiment with a simple structure.
[0057]
【The invention's effect】
According to the present invention, an organic semiconductor element having a simple configuration can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating a layer configuration of an organic semiconductor device according to an embodiment of the present invention.
FIG. 2 is a schematic view illustrating a manufacturing process of the transistor element according to the first embodiment of the present invention.
FIG. 3 is a schematic view illustrating a manufacturing process of the transistor element according to the first embodiment of the present invention.
FIG. 4 is a schematic view illustrating a manufacturing process of the transistor element according to the first embodiment of the present invention.
FIG. 5 is a schematic view illustrating a manufacturing process of the transistor element according to the first embodiment of the present invention.
FIG. 6 is a schematic view illustrating a manufacturing process of the transistor element according to the first embodiment of the present invention.
FIG. 7 is a schematic view showing a transistor device obtained by a process for manufacturing a transistor device according to Example 1 of the present invention.
FIG. 8 is a schematic diagram illustrating a state where a power supply is connected to the transistor element according to the first embodiment of the present invention.
FIG. 9 is a graph showing current-voltage characteristics of the transistor element according to the first embodiment of the present invention.
FIG. 10 is a schematic diagram showing each functional area of an IC card having in-plane transistor elements according to a second embodiment of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 Base material 2 First electrode 3 Organic semiconductor layer 4 Second electrode 5 Protective layer 6 Collector electrode 7 Base electrode 8 Emitter electrode 9 Insulator substrate 10 First conductor layer 11 Organic semiconductor layer 12 Second conductor layer 13 Protective insulating layer 14 Collector electrode 15 Base electrode 16 Emitter electrode 17 Magnetic recording area 18 ROM array area 19 Fuse array area 20 Data input / output terminal 21 IC card

Claims (10)

Having a pair of electrodes facing each other on the substrate, and an organic semiconductor layer between the pair of electrodes,
A first extraction electrode connected to a first electrode of the pair of electrodes;
A second extraction electrode connected to a second electrode of the pair of electrodes;
An organic semiconductor device comprising: a third extraction electrode connected to the organic semiconductor layer. The first electrode, the organic semiconductor layer, and the second electrode are substantially stacked on the base material in the order of the first electrode, the organic semiconductor layer, and the second electrode. The organic semiconductor device according to claim 1, wherein: The surface on the side where the organic semiconductor layer is provided of the first electrode has a portion where the organic semiconductor layer is provided and a protruding portion where the organic semiconductor layer is not provided. 3. The organic semiconductor device according to 2. The organic semiconductor element according to claim 3, wherein the protruding portion where the organic semiconductor layer is not provided is a peripheral portion of a portion where the organic semiconductor layer is provided. The surface of the organic semiconductor layer on the side where the second electrode is provided has a portion where the second electrode is provided and a protruding portion where the second electrode is not provided. The organic semiconductor device according to claim 2. The organic semiconductor device according to claim 5, wherein the protruding portion where the second electrode is not provided is a peripheral portion of a portion where the second electrode is provided. An insulating member that covers the first electrode, the organic semiconductor layer, and the second electrode on the base material, wherein the first extraction electrode, the second extraction electrode, and the third extraction electrode 7. The organic semiconductor device according to claim 1, wherein the insulating member is taken out from an upper surface. The organic semiconductor element according to claim 1, wherein a thickness of the organic semiconductor layer is 100 nm or less. An RF modulation circuit comprising the organic semiconductor device according to claim 1. An IC card comprising the organic semiconductor device according to claim 1.

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