JP2011181758A - Method of manufacturing organic switching element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic switching element which has enhanced reproducibility by suppressing variance in switching characteristics of the organic switching element. <P>SOLUTION: The method of manufacturing the organic switching element having a structure wherein an organic thin film containing metal particulates is sandwiched between two electrodes, includes (A) a stage of forming an organic lower film containing a first polymer compound on a lower electrode, (B) a stage of vapor-depositing first metal particulates on the organic lower film, (C) a stage of forming an organic upper film in which second metal particulates identical to or different from the first metal particulates are dispersed with a second polymer compound of the same kind with or different kind from the first polymer compound as a dispersant, on the first metal particulates successively to the stage (B), and (D) a stage of creating the structure in which the organic thin film comprising the organic upper film and organic lower film and containing the metal particulates is sandwiched between the upper electrode and lower electrode, wherein each of the first polymer compound and second polymer compound has a dithiocarbamate group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a switching element in which an organic bistable material is sandwiched between two electrodes, which is expected to be applied to an organic memory element or the like.

  Compared to conventional semiconductor materials, the characteristics of organic electronic materials having characteristics such as low cost and high flexibility have made remarkable progress. In particular, the application of organic bistable materials to high-density organic memory devices and the like, in which switching phenomena are observed when a voltage is applied to the material, the circuit current suddenly increases above a certain voltage and the switching phenomenon is observed. ing.

  The operation mechanism of such an element is achieved by reversible switching between two resistance states. For example, Yang Yang et al. In aluminum, copper, silver, gold, nickel, magnesium, organic semiconductors such as aminoimidazole dicarbonitrile (AIDCN), hydroxyquinoline aluminum (Alq), and organic insulators such as polystyrene and PMMA, By forming a thin film of highly conductive material such as indium, calcium, lithium, etc., or dispersing it as fine particles, bistability in a high resistance state and a low resistance state can be obtained by applying a voltage. It was shown that it is a non-volatile memory in which information is held (see Patent Documents 1 and 2 and Non-Patent Document 1).

  Patent Document 3 discloses platinum or rhodium having an average particle size of 5 nm or less as conductive fine particles in an organic bistable material layer having an electron-donating functional group and an electron-accepting functional group in one molecule. A switching element in which fine particles are dispersed is described. It is described that fine particles with little variation in particle size can be uniformly dispersed in a fine particle dispersion layer having a small film thickness, and a switching element with stable characteristics can be obtained.

In organic bistable materials in which fine metal particles are conventionally proposed, stabilization of device characteristics and cost reduction are important issues. By increasing the dispersibility of fine metal particles in organic semiconductors or organic insulators. It is considered to be achieved. On the other hand, the techniques described in Patent Documents 1 and 2 and Non-Patent Document 1 do not specifically propose a dispersant for metal fine particles in an organic semiconductor or an organic insulator. Further, although the invention described in Patent Document 3 describes that an organic bistable material having an electron donating functional group and an electron accepting functional group in one molecule is used, No mention is made that the content of the conductive fine particles can be reduced and the device has current bistability.
In addition, the conventional switching element has a problem that the variation in switching characteristics is large and the yield when arrayed is greatly reduced.

As a result of diligent studies to solve the above-mentioned problems, the present inventors have adopted a polymer compound containing a dithiocarbamate group as a metal fine particle dispersant, thereby improving dispersibility in organic semiconductors and organic insulators. As a result, the content of the metal fine particles was reduced and the stability of the switching element was successfully improved.
In particular, by preliminarily arranging the metal fine particles on the lower electrode of the switching element, that is, by making the metal fine particles present at a higher concentration on or near the surface of the lower electrode, the switching characteristics of the element Succeeded in improving the reproducibility by suppressing the variation of

That is, the present invention provides a switching element having a structure in which an organic thin film containing metal fine particles is sandwiched between two electrodes as a first aspect.
A) forming an organic underlayer containing the first polymer compound on the lower electrode;
B) depositing first metal fine particles on the organic underlayer;
C) Subsequently, second metal fine particles that are the same as or different from the first metal fine particles are dispersed on the second polymer compound as a dispersant of the same or different type as the first polymer compound. Forming an organic overcoat, and
D) forming an organic thin film containing metal fine particles comprising the organic upper film and the organic lower film into a structure sandwiched between an upper electrode and a lower electrode,
The first polymer compound and the second polymer compound are polymer compounds having a dithiocarbamate group and a weight average molecular weight of 500 to 5,000,000.
The present invention relates to a method for manufacturing an organic switching element.
As a second aspect, the vapor deposition step of B) relates to the manufacturing method according to the first aspect, which is performed using an arc plasma gun.
As a third aspect, the organic underlayer formed in the step A) relates to the manufacturing method according to the first aspect, which is an ultrathin film having a thickness of 10 nm or less.
As a 4th viewpoint, the said upper side electrode and lower side electrode are related with the manufacturing method as described in a 1st viewpoint which is a vapor deposition film of an electroconductive metal.
As a fifth aspect, the first metal fine particles and the second metal fine particles are at least one selected from the group consisting of gold, silver, platinum, copper, nickel, ruthenium, rhodium, palladium, osmium, and iridium. The manufacturing method according to the first aspect.
As a sixth aspect, the first metal fine particle and the second metal fine particle are related to the production method according to the first aspect, wherein the average particle diameter is a metal fine particle having a particle size of 1 nm to 500 nm.
As a seventh aspect, the first polymer compound and the second polymer compound are related to the production method according to the first aspect, which is a branched polymer compound.
As an eighth aspect, the first polymer compound and the second polymer compound are related to the production method according to the first aspect, which is a branched polymer compound represented by the formula (1).
(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ represent an alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group having 1 to 5 carbon atoms, or 7 to 7 carbon atoms, respectively. 12 represents an arylalkyl group, or R ² and R ³ may be bonded to each other to form a ring together with the nitrogen atom, and A ¹ represents formula (2) or formula (3):
(In the formula, A ² has 1 to 30 carbon atoms which may contain an ether bond or an ester bond.
Represents a linear, branched or cyclic alkylene group, and Y ¹ , Y ² , Y ³ or Y ⁴ each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or 1 carbon atom. To 20 alkoxy groups, a halogen atom, a nitro group, a hydroxyl group, an amino group, a carboxyl group or a cyano group; N represents the number of repeating unit structures and represents an integer of 2 to 100,000. )

In the organic switching element according to the present invention, such as a fine particle dispersed organic memory element, the metal fine particles are previously disposed on the lower electrode, and more specifically, the metal fine particles are formed on the lower electrode using an arc plasma gun. Vapor deposition can reduce variation in switching characteristics, and in particular, can improve the reproducibility of the current value in the ON state.
In addition, in the organic switching element of the present invention, by using metal fine particles dispersed by a polymer compound having a dithiocarbamate group as a dispersant, the dispersibility of the metal fine particles is high, so that switching characteristics are stable. The amount of metal fine particles used can be reduced, and the cost of the switching element can be reduced.

FIG. 1 is a diagram showing an embodiment of a switching element of the present invention. FIG. 2 is a diagram showing a TEM image (FIG. 2 (a)) and a particle size distribution (FIG. 2 (b)) of gold fine particles deposited by an arc plasma gun in Example 1. FIG. FIG. 3 is a diagram showing two kinds of voltage operations (sawtooth sweep (FIG. 3A), triangular wave sweep (FIG. 3B)) used in the example. FIG. 4 is a graph showing the current density vs. voltage (JV) characteristics of the switching element fabricated in Example 1. FIG. 5 shows the range of current density measured when the ON / OFF switching of the element of Example 1 (FIG. 5A) and the element of Comparative Example 1 (FIG. 5B) was performed 10 times each. It is a graph to show. In the figure, squares and circles indicate average values of current density in the high conductive state and the low conductive state, respectively, and correspond to one switching per group. Error bars indicate the range of current density observed in each measurement.

Details for carrying out the present invention will be described below.
A method for producing an organic switching element having a structure in which an organic thin film containing metal fine particles of the present invention is sandwiched between two electrodes,
A) forming an organic underlayer containing the first polymer compound on the lower electrode;
B) depositing first metal fine particles on the organic underlayer;
C) Subsequently, second metal fine particles that are the same as or different from the first metal fine particles are dispersed on the second polymer compound of the same type or different from the first polymer compound. Forming an organic overcoat, and
And D) forming an organic thin film containing metal fine particles comprising the organic upper film and the organic lower film into a structure sandwiched between the upper electrode and the lower electrode.

  FIG. 1 is a schematic diagram showing an embodiment of a switching element 1 manufactured by the manufacturing method of the present invention. The switching element 1 has a structure in which a lower electrode 2, an organic lower film 3, metal fine particles 4, an organic upper film 5, and an upper electrode 6 are laminated on a substrate. The lower electrode 2 and the upper electrode 6 are electrically connected to each other. Connections 7 and 8 are connected to the electronic control unit 9, respectively. Among these, metal fine particles 10 are dispersed in the organic upper film 5.

<A) Stage>
First, an organic underlayer containing the first polymer compound is formed on the lower electrode.
In addition, as a formation method of a lower electrode, a vacuum evaporation method, a sputtering method, a coating method, an ink jet method, a printing method, a sol-gel method, and the like can be given. Further, as a patterning method, a photolithography method, an ink jet method, Examples thereof include printing methods such as screen printing, offset printing and letterpress printing, microcontact printing methods, vapor deposition methods using shadow masks, and methods combining a plurality of these methods.
Lower electrode materials include Au, Pt, Ag, Al, Cu, Rh, Ir, In, Ni, Pd, As, Se, Te, Mo, W, Mg, Zn, and other metals, Mg / Cu, Mg / Alloys such as Ag, Mg / Al, Mg / In, metal oxides such as SnO ₂ , InO ₂ , ZnO, InO ₂ · SnO ₂ (ITO), Sb ₂ O ₅ · SnO ₂ (ATO), conductive polyaniline, conductive Examples thereof include conductive polymers such as polypyrrole and conductive polythiophene, and carbon.

  The first polymer compound used in the present invention is composed of a polymer compound having a dithiocarbamate group, and the weight average molecular weight Mw measured in terms of polystyrene by gel permeation chromatography is in the range of 500 to 5,000,000. Is used. It preferably has a weight average molecular weight of 1,000 to 1,000,000, more preferably 2,000 to 500,000, and particularly preferably 3,000 to 200,000. Further, the degree of dispersion Mw (weight average molecular weight) / Mn (number average molecular weight) of the first polymer compound is 1.0 to 7.0, preferably 1.1 to 6.0, and more preferably. Is 1.2 to 5.0.

The method for forming the organic underlayer containing the first polymer compound can be appropriately selected from a vapor deposition method or a solution coating method.
When the solution coating method is selected, the first polymer compound and optionally other polymer compounds are dissolved in an appropriate solvent to form a solution, and the solution is coated on the lower electrode and annealed. An organic underlayer is formed.

Specific examples of the solution coating method include spin coating method, blade coating method, dip coating method, roll coating method, bar coating method, die coating method, ink jet method, and printing method (such as letterpress, letterpress, flat plate, and screen printing). Among them, it can be applied in a single hour, so even a highly volatile solution can be used, it can be applied with high uniformity, and it is spin because of its low cost. It is preferable to employ a coating method.
The solvent used in the solution coating method is selected from aromatic solvents such as toluene, xylene and dichlorobenzene, ketone solvents such as methyl ethyl ketone and cyclohexanone, and ether solvents such as tetrahydrofuran.

When using other polymer compounds, polystyrene, polyesters, polyvinyl alcohol, polycarbonate, polyacrylic acids such as polymethyl acrylate, polymethacrylic acids such as polymethyl methacrylate, polyolefins, polyamides, polyimides, Materials such as polyurethanes, polyacetals, polysilicones, polyvinyl pyridine, and hyperbranched polymers represented by the following formula (4) are applicable, and polystyrene, polymethyl methacrylate, and the like are preferably used.

  The concentration of the solution in which the first polymer compound (and other polymer compound if desired) is dissolved is not particularly limited. However, the first polymer compound (and other other compounds if desired) is not limited to the total mass of the solution. The total mass (total mass) of the polymer compound is preferably 0.1 to 80% by mass, more preferably 1 to 50% by mass.

The organic underlayer thus formed plays a role as a protective film that prevents the lower electrode from being damaged by the subsequent deposition of metal fine particles.
The organic underlayer is preferably an ultrathin film having a thickness of 10 nm or less.

<B) Stage>
Next, first metal fine particles are vapor-deposited on the organic upper film produced in <A) stage>.
Examples of the metal species of the first fine metal particles used here include Au, Pt, Ag, Al, Cu, Rh, Ir, In, Ni, Pd, As, Se, Te, Mo, W, Mg, Zn, and the like. Preferably, Au, Ag, Pt and Cu are mentioned.
The metal fine particles have an average particle size of 1 to 500 nm, preferably 1 to 100 nm,
More preferably, those having a thickness of 1 to 10 nm can be used.

The first metal fine particles can be obtained by reducing the metal ions. Methods for reducing metal ions include, for example, a method of irradiating light with a high-pressure mercury lamp, a method of adding a compound having a reducing action (reducing agent), etc. The latter method, ie, an aqueous solution in which a metal salt is dissolved. The method of adding a reducing agent is advantageous in production without requiring a special apparatus.
Examples of the metal salt include chloroauric acid, silver nitrate, copper sulfate, copper nitrate, platinum chloride, Pt (dba) ₂ [dba = dibenzylideneacetone], Pt (cod) ₂ [cod = 1,5-cycloocta Diene], PtMe ₂ (cod), palladium chloride, palladium acetate, palladium nitrate, Pd (dba) ₂ , rhodium chloride, rhodium acetate, ruthenium chloride, ruthenium acetate, Ru (cod) (cot) [cot = cyclooctatriene] Iridium chloride, iridium acetate, Ni (cod) _{2 and the} like.
The reducing agent is not particularly limited, and various commonly used ones can be used, and it is preferable to select the reducing agent according to the metal species to be contained. For example, borohydride alkali metal salts such as sodium borohydride and potassium borohydride conventionally used as reducing agents, lithium aluminum hydride, potassium aluminum hydride, cesium aluminum hydride, aluminum beryllium hydride, hydrogen Aluminum hydride salts such as aluminum magnesium hydride and calcium aluminum hydride, hydrazine compounds, citric acid or a salt thereof, succinic acid or a salt thereof, ascorbic acid or a salt thereof, and the like can be used.
The addition amount of the reducing agent is preferably 1 to 50 mol with respect to 1 mol of the metal ion. If the amount is less than 1 mol, the reduction is not sufficiently performed, and if it exceeds 50 mol, the stability against aggregation is lowered. More preferably, it is 1.5 to 10 mol.
Note that it is desirable that the amount of impurity ions such as sodium, potassium, and calcium ions contained in the metal fine particles is smaller because the repeatability of the device is improved. These impurity ions are washed by a reprecipitation method using a solvent such as water or alcohol, a method in which metal fine particles are dissolved in an organic solvent incompatible with water and separated from water, or a method using an ion exchange resin. Can be removed.

The vapor deposition of the first metal fine particles on the organic upper film is preferably performed using an arc plasma gun.
An arc plasma gun is a type of vacuum arc vapor deposition source that has a mechanism for evaporating electrode materials by arc discharge. By arranging a columnar cathode coaxially inside the cylindrical anode and applying a pulse voltage between the anode and the cathode, the cathode material can be provided as nanometer-sized fine particles. The particle size of the fine particles can be controlled by the pulse voltage, and the number of particles can be controlled by the number of pulses. A nanoparticle layer having a particle diameter of 1 to 10 nm obtained with a pulse voltage of 100 to 300 V and a pulse number of 10 to 500 times can be suitably used.

<C) Stage>
Subsequently, an organic upper film in which the second metal fine particles are dispersed by the second polymer compound as a dispersant is formed on the deposited metal fine particles.
Examples of the metal species of the second metal fine particles used here include the same metal species as the first metal fine particles used in the <B) stage>, which are the same as or different from the metal species used as the first metal fine particles. Metal species can be used.
As the second polymer compound, a polymer compound having a dithiocarbamate group used in <A)> and having a weight average molecular weight of 500 to 5,000,000 can be used. A compound of the same type or a different type from the molecular compound can be used.

The method for forming the organic upper film in which the second metal fine particles are dispersed by the second polymer compound on the vapor-deposited metal fine particles can be appropriately selected from a vapor deposition method or a solution coating method. .
When the solution coating method is selected, for example, the second metal fine particles treated with the second polymer compound and optionally other polymer compounds are dissolved (or dispersed) in a solvent to form a solution (or dispersion). Then, the solution (or dispersion) is applied onto the deposited metal fine particles, and annealing is performed to form an organic upper film.

The solution (or dispersion liquid) of the second metal fine particles treated with the second polymer compound is a mixture of the second polymer compound and the metal salt, a reducing agent is added to the resulting mixture, and metal ions are added. Can be obtained by reducing
The metal salt and reducing agent used here can be appropriately selected from those mentioned in the above <B) stage>.
The blending ratio of the second polymer compound to the second metal fine particles is preferably 50 to 2000 parts by mass with respect to 100 parts by mass of the second metal fine particles. When the amount is less than 50 parts by mass, the dispersibility of the second metal fine particles is insufficient, and when the amount exceeds 2000 parts by mass, the organic matter content increases, and problems such as physical properties tend to occur. More preferably, it is 100-1000 mass parts.

  In addition, specific examples of the solution coating method used here, the solvent to be used, other polymer compounds that can be added as desired, and the concentration of the solution (or dispersion) are appropriately selected from those listed in <A) Step>. be able to.

  In the organic upper film thus formed, the second metal fine particles are dispersed and stabilized by the second polymer compound, and a dispersion state is created for the metal fine particles having an average particle diameter of 10 nm or less, for example, about 3.5 nm. be able to.

<D) Stage>
Subsequently, an organic thin film containing metal fine particles composed of the organic upper film and the organic lower film is formed into a structure sandwiched between the upper electrode and the lower electrode.
Specifically, an upper electrode is formed on the organic upper film formed in <C) stage>. The formation method and the upper electrode material used here can be appropriately selected from those listed as the formation method and electrode material for the lower electrode in <A) stage>.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

[Synthesis Example 1: Production of Gold Fine Particles (HPS-Au) Treated with Dithiocarbamate-Containing Polymer Compound]
0.5 g of branched polymer (HPS) represented by the following formula (4) was dissolved in 200 ml of tetrahydrofuran (THF), and 6.7 mL of a 30 mM chloroauric acid aqueous solution was added thereto. Subsequently, 10 mL of 0.1 M sodium borohydride aqueous solution was dripped over about 5 minutes. The solution turned brown with the dropwise addition. After stirring for 30 minutes, THF was distilled off under reduced pressure to deposit a black precipitate insoluble in water. This was filtered and washed with ion-exchanged water, and then 20 ml of THF was added and dissolved, followed by reprecipitation with methanol. The obtained powder was collected and dried.
As a result of obtaining the sodium and gold contents in the composition by an inductively coupled plasma optical emission spectrometer (ICP-AES), they were 150 ppm and 6.4 wt%, respectively. Moreover, as a result of calculating | requiring a chlorine content by ion chromatography [ICS-500 by a Dionex company], it was 63 ppm.
(In the above formula (4), Et represents an ethyl group.)

[Example 1]
A switching element as shown in FIG. 1 was prepared by the following procedure.
(1) Glass cleaning Micro slide glass (Iwaki Glass Co., Ltd. (current: AGC Techno Glass Co., Ltd.) cut to about 2 cm × 2 cm is neutralized with 3% neutral detergent (White-7: ui Kasei Co., Ltd.) → Ion Ultrasonic cleaning was performed three times (5 minutes, 10 minutes, and 15 minutes) in the order of exchanged water → acetone → ethanol, and boiled cleaning with ethanol and UV-ozone cleaning were performed for 20 minutes immediately before use for device fabrication. It was.
(2) Formation of lower electrode The formation of the lower electrode was performed using an ULVAC vacuum deposition apparatus, and Al (Nilaco Corporation) was applied at a vacuum degree of 4 × 10 ⁻⁴ Pa or less and a deposition rate of 3 to ⁴ L / min. A 70 nm film was formed. In addition, a W boat made by Furuuchi Chemical Co., Ltd. was used as the evaporation source board.
(3) Formation of organic underlayer HPS 1.7 wt% dichlorobenzene solution represented by the above formula (4) is prepared and stirred overnight, and then spin-coated under a condition of 4,500 rpm for 30 seconds through a filter. Done
Thereafter, annealing was performed at 150 ° C. for 30 minutes.
(4) Deposition of gold fine particles by arc plasma gun Using a hyper arc plasma gun ARL-300 (manufactured by ULVAC, Inc.), gold fine particles were deposited on the organic underlayer. Film formation was performed at a vacuum of 7.0 × 10 ⁻⁶ Torr (9.3 × 10 ⁻⁴ Pa) or less, a pulse voltage of 100 V, a pulse interval of 1 / second, and a pulse count of 20 times.
FIG. 2 shows a TEM image (FIG. 2A) and a particle size distribution (FIG. 2B) of gold fine particles deposited by an arc plasma gun. According to this, it was confirmed that gold fine particles having an average particle diameter of 1.8 nm and a standard deviation of the particle diameter of 0.4 nm could be deposited.
(5) Formation of organic overcoat A dichlorobenzene solution of HPS 3 wt% represented by the above formula (4) and HPS-Au 1 wt% prepared in Synthesis Example 1 was prepared and stirred overnight, and then passed through a filter. Spin coating was performed at 000 rpm for 30 seconds, and annealing was performed at 150 ° C. for 30 minutes. The film thickness of the element after forming the organic upper film was about 120 nm.
(6) Formation of upper electrode Using the same vacuum deposition apparatus as the formation of the upper electrode, the upper electrode is formed using Al (Niraco Co., Ltd.) with a degree of vacuum of 4 × 10 ⁻⁴ Pa or less and a deposition rate of 3-4 Å / sec. To 70 nm. In addition, a W boat made by Furuuchi Chemical Co., Ltd. was used as the evaporation source board.

[Comparative Example 1]
(4) A switching element of Comparative Example 1 was produced in the same procedure as Example 1 except that the gold fine particles were not deposited by the arc plasma gun.

[Measurement of current density vs. voltage (JV) characteristics]
The measurement of the JV characteristics of the element obtained in Example 1 was performed by using Agilent E5260 / E5270 and GRAIL series cryogenic prober (GRAIL-ENTRY), putting the element in a vacuum chamber and reducing the pressure to 1 pa or less. Went.
Here, as shown in FIG. 3, the voltage operation was performed in two types of operations: sawtooth-sweep (saw tooth-sweep, FIG. 3 (a)) and triangular wave sweep (triangle-sweep, FIG. 3 (b)). .
FIG. 4 shows the JV characteristics of the device of Example 1.
When the sawtooth sweep is first performed on the switching element of Example 1, a high resistance state (low conduction state, OFF state) is shown in a low voltage region of 0.1 to 3.0 V, and when about 3.0 V, A current flowed and a low resistance state (high conductivity state, ON state) was shown. The threshold voltage (V _th ) at this time was 2.75V. Further, an NDR (Negative differential resistance) phenomenon in which the current value decreases as the voltage is increased was observed. As long as the sawtooth sweep was performed, the current value showed almost the same behavior. Further, when the voltage operation was performed on the element for the first time, the current value was lower than that for the second time and thereafter. The first voltage operation with respect to this element can be called “elementization”, and it was estimated that a phenomenon different from the first time and the second time or later occurred in the organic layer.
When the triangular wave sweep is performed on the switching element of the first embodiment, the same behavior as the sawtooth sweep is shown at the time of increasing the voltage from 0.0 V to 10.0 V, and the voltage from 10.0 V to 0.0 V is decreased. In the voltage operation, the low resistance state was maintained even in the low voltage region of 0.1 to 3.0 V, that is, the current bistable characteristics were exhibited.

[Measurement of reproducibility]
For each of the switching elements fabricated in Example 1 and Comparative Example 1, ON / OFF switching was performed 10 times continuously, and the variation in current value was measured. In addition, in the “read” operation for determining the ON / OFF state, the current value at 1.8 V was read. The obtained results are shown in FIG.

  As shown in FIG. 5 and Table 1, regarding the ON current, it was confirmed that the variation in the current value of the element of Example 1 was smaller than that of the element of Comparative Example 1, and the result was that the element was excellent in reproducibility. Obtained.

DESCRIPTION OF SYMBOLS 1 ... Switching element 2 ... Lower electrode 3 ... Organic lower film 4 ... Metal fine particle 5 ... Organic upper film 6 ... Upper electrode 7, 8 ... Electrical connection 9 ...・ Electronic control unit 10 ... metal fine particles

JP-T-2004-513513 JP 2005-101594 A JP 2004-200569 A

PROCEEDINGS OF THE IEEE, 93, 7 (2005)

Claims (8)

In a method of manufacturing a switching element having a structure in which an organic thin film containing metal fine particles is sandwiched between two electrodes,
A) forming an organic underlayer containing the first polymer compound on the lower electrode;
B) depositing first metal fine particles on the organic underlayer;
C) Subsequently, second metal fine particles that are the same as or different from the first metal fine particles are dispersed on the second polymer compound as a dispersant of the same or different type as the first polymer compound. Forming an organic overcoat, and
D) forming an organic thin film containing metal fine particles comprising the organic upper film and the organic lower film into a structure sandwiched between an upper electrode and a lower electrode,
The first polymer compound and the second polymer compound are polymer compounds having a dithiocarbamate group and a weight average molecular weight of 500 to 5,000,000.
Manufacturing method of organic switching element. The manufacturing method according to claim 1, wherein the deposition step of B) is performed using an arc plasma gun. The manufacturing method according to claim 1, wherein the organic underlayer formed in step A) is an ultrathin film having a thickness of 10 nm or less. The manufacturing method according to claim 1, wherein the upper electrode and the lower electrode are deposited films of conductive metal. The first metal fine particles and the second metal fine particles are at least one selected from the group consisting of gold, silver, platinum, copper, nickel, ruthenium, rhodium, palladium, osmium, and iridium. The manufacturing method as described. The manufacturing method according to claim 1, wherein the first metal fine particles and the second metal fine particles are metal fine particles having an average particle diameter of 1 nm or more and 500 nm or less. The manufacturing method according to claim 1, wherein the first polymer compound and the second polymer compound are branched polymer compounds. The manufacturing method according to claim 1, wherein the first polymer compound and the second polymer compound are branched polymer compounds represented by the formula (1).
(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ represent an alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group having 1 to 5 carbon atoms, or 7 to 7 carbon atoms, respectively. 12 represents an arylalkyl group, or R ² and R ³ may be bonded to each other to form a ring together with the nitrogen atom, and A ¹ represents formula (2) or formula (3):
(In the formula, A ² has 1 to 30 carbon atoms which may contain an ether bond or an ester bond.
Represents a linear, branched or cyclic alkylene group, and Y ¹ , Y ² , Y ³ or Y ⁴ each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or 1 carbon atom. To 20 alkoxy groups, a halogen atom, a nitro group, a hydroxyl group, an amino group, a carboxyl group or a cyano group; N represents the number of repeating unit structures and represents an integer of 2 to 100,000. )