WO2016052535A1 - Oxide thin film element, and production method and production device therefor - Google Patents

Abstract

Provided are: a production method in which a low-temperature printing process is used to produce a metal oxide thin film element which serves as a conductive layer or a semiconductor layer; a production device; and an oxide thin film element produced therewith. In this method for producing an oxide thin film element of a conductor or a semiconductor comprising a metal oxide, a step in which a coating film, which is formed by applying a coating of a solution including a metal compound serving as a precursor of the metal oxide, is irradiated with ultraviolet light under a gas atmosphere, and a step in which the coating film is pressurized at a pressure equal to or greater than normal pressure are simultaneously or sequentially performed. As a result, an oxide thin film element of a conductor or a semiconductor can be formed on a flexible substrate.

Description

Oxide thin film element, manufacturing method and manufacturing apparatus thereof

The present invention relates to an oxide thin film element having excellent electrical characteristics, a manufacturing method thereof, and a manufacturing apparatus for performing the manufacturing method.

Recently, in the world of the electronic industry, flexible electronic devices have attracted a great deal of attention, and techniques for manufacturing electronic devices on a flexible substrate such as plastic by a low temperature printing process have attracted attention.

An organic polymer having conjugated π electrons is promising as a flexible electronic device, but it is extremely difficult to have both high carrier mobility necessary for functioning as an electronic device and durability against heat and high voltage. In recent years, a thin film made of a conductive amorphous oxide material has attracted attention as a material having both high carrier mobility and durability. For example, a manufacturing technique of a field effect transistor using an amorphous oxide composed of In, Ga, and Zn as a semiconductor layer on a flexible substrate is known. A sputtering method that requires high vacuum is used as a method for manufacturing this thin film (see Patent Document 1).

On the other hand, solution coating processes such as various printing methods and blade coating methods have been proposed as technologies for producing large-area flexible electronic devices such as electronic paper and sheet-type sensors at low energy and low cost. A technique for manufacturing a thin film device made of a metal oxide having a high electronic function by using these coating methods has been reported (see Non-Patent Document 1).

As a method for producing a metal oxide thin film by a solution coating process, a sol-gel method using a metal alkoxide compound as a raw material and an organometallic thermal decomposition method using an organic metal compound as a raw material are known (see Non-Patent Document 2). In these methods, it is necessary to heat and sinter the coating film at a high temperature of 400 ° C. or higher in order to sufficiently perform the respective reactions of conversion from the raw material to metal oxide and sintering for enhancing the electronic function. It is.

A technique for producing a metal oxide semiconductor thin film having high electron mobility by heating at a low temperature by using a cluster material as a coating raw material has been reported (see Non-Patent Document 3).

A technique for lowering the heating temperature by irradiating a thin film of a metal compound formed on a substrate having low heat resistance with ultraviolet light has been reported (see Non-Patent Document 4).

The inventor has proposed a method and an apparatus for manufacturing a silicon oxide film or the like by coating and conversion (see Patent Documents 2, 3, and 4).

JP 2011-181800 A International Publication No. 2006-019157 JP 2008-159824 A JP 2009-224456 A

E. Fortunato et al., Advanced Materials, Vol. 24,2945 (2012) M.M. Kim et al., Nature Materials, Vol. 10, 382-388 (2010) H. Sirringhaus et al., Nature Materials, Vol. 10, 45-50 (2010) L. Lu et al., AIP Advanced, Vol. 2,032111 (2012)

The conventional method for producing a metal oxide thin film by a solution coating process requires a step of heating and baking the coating film at a high temperature of 400 ° C. or more as described above. Since the heat-resistant temperature of the conductive plastic substrate is 200 ° C. or less, there is a problem that it is not suitable for manufacturing an electronic device on a plastic substrate.

Regarding conventional methods of using cluster materials as coating materials, metal cluster materials are generally difficult to synthesize, expensive as raw materials, and many are unstable in the atmosphere. There was a problem that it was not suitable for production.

In the conventional technology for lowering the heating temperature by irradiating with ultraviolet light, the reported heating temperature is 250 ° C. or higher, and it has high electronic performance on a general-purpose plastic substrate that is practically required. Production of an oxide thin film is extremely difficult.

The present invention is intended to solve these problems, and is a method for manufacturing a metal oxide thin film element to be a conductive layer or a semiconductor layer such as an electrode on a general-purpose plastic substrate having a heat-resistant temperature of 200 ° C. or less by a low-temperature printing process. It is an object to provide a method, a manufacturing apparatus, and a manufactured oxide thin film element.

The present invention has the following features in order to achieve the above object.

The method of the present invention is a method for producing a conductor or semiconductor oxide thin film element made of a metal oxide, and is a coating formed by coating a solution containing a metal compound to be a precursor of the metal oxide The step of irradiating the film with ultraviolet rays in a gas atmosphere and the step of pressurizing the coating film at a pressure equal to or higher than normal pressure are performed simultaneously or sequentially. For example, the pressure is preferably 0.6 MPa or more. For example, the metal compound serving as the precursor includes one or more metals of In, Zn, Ga, Sn, Cu, and Ni. For example, the ultraviolet light has a wavelength of 240 nm or less. For example, in the pressurizing step, the medium for pressurization is either a gas or a liquid introduced into the atmosphere, or both. For example, in the step of irradiating with ultraviolet rays, the coating film is maintained at a temperature of room temperature to 200 degrees. The oxide thin film element of the present invention is manufactured on the flexible substrate by the above-described manufacturing method.

The apparatus of the present invention is an apparatus for manufacturing a conductor or semiconductor oxide thin film element made of a metal oxide, and is a coating formed by coating a solution containing a metal compound that becomes a precursor of the metal oxide The apparatus includes a device for controlling the gas atmosphere to irradiate ultraviolet rays from an ultraviolet lamp and a device for pressurizing the coating film at a pressure higher than normal pressure. For example, the manufacturing apparatus controls a pressure-resistant reaction chamber provided with the pressurizing device, an ultraviolet lamp that irradiates ultraviolet light directly above the coating film in the pressure-resistant reaction chamber, and a pressure in the pressure-resistant reaction chamber. Device. In addition, for example, the manufacturing apparatus includes an ultraviolet lamp device unit that irradiates the coating film with ultraviolet light from directly above, a pressure-resistant reaction chamber that includes the pressurizing device, the ultraviolet lamp device unit, And a transfer device for transferring the coating film between the pressure-resistant reaction chambers.

According to the present invention, it is possible to realize a thin film element including a conductive layer or a semiconductor layer made of a metal oxide based on a general-purpose plastic film having a heat resistant temperature of 200 ° C. or less. Unlike conventional semiconductor elements formed from organic coatings, the elements can be composed of metal oxides with higher electric carrier mobility, conductivity, and reliability. Effects of longer life, longer life, and improved stability.

According to the manufacturing method and the manufacturing apparatus of the present invention, it is possible to use a general-purpose plastic film having a heat resistant temperature of 200 ° C. or less that is inexpensive and has a large amount of distribution. That is, the manufacturing apparatus of the present invention irradiates the metal compound with the metal oxide by irradiating the substrate coated with the metal compound with ultraviolet light while maintaining a certain temperature of 200 ° C. or less in a controlled gas atmosphere. The oxide can be densified and physical / electrical performance can be improved by the effect of the pressure treatment performed at the same time as or before and after the conversion into the oxide. It is possible to easily produce a thin film whose properties are controlled depending on the use, such as whether a metal oxide is used as a conductive layer or a semiconductor layer.

Moreover, according to the manufacturing method and the manufacturing apparatus of the present invention, a high-performance electronic device such as a thin film transistor can be manufactured by a printing method. That is, the metal oxide of the present invention is an electrode or electrode having the same high electrical performance even at a temperature of 200 ° C. or less, which is much lower than the heat treatment of 400 ° C. or more performed by the conventional sol-gel method or thermal decomposition method. A semiconductor thin film is obtained. Therefore, it is possible to manufacture a large area thin film device with a short time and low energy cost and without requiring large facilities such as heat insulation facilities. As a result, it is possible to reduce manufacturing device costs and manufacturing costs.

Conventionally, in order to form a conductive oxide or semiconductor oxide thin film made of a metal oxide on a plastic substrate having low heat resistance, there is only a method using a vacuum process such as vapor deposition or sputtering. Whereas a film-forming chamber and a high-performance vacuum evacuation device were required, a conductive or semiconductor oxide thin film element made of a high-performance metal oxide on a plastic substrate by a simple device according to the present invention. It became possible to produce.

Moreover, according to the manufacturing method and the manufacturing apparatus of the present invention, it is possible to continuously form metal oxide thin film elements by roll-to-roll, which is difficult in the conventional vacuum process. According to the manufacturing method and manufacturing apparatus of the present invention, mass production of a large area and a flexible device can be realized with simple and low-cost means.

According to the present invention, a high-performance electronic element such as a thin film transistor can be manufactured at low cost on a plastic sheet base material that is lightweight, flexible, and highly moldable. Useful for manufacturing flexible devices.

The conceptual diagram of the thin film forming apparatus for implementing simultaneously ultraviolet irradiation and pressurization of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The conceptual diagram of the thin film formation apparatus for performing sequentially ultraviolet irradiation and pressurization of this invention. The infrared absorption spectrum of the complex oxide thin film of indium zinc produced in 1st Embodiment. FIG. 6 is a graph showing transfer characteristics of the thin film transistor manufactured in the first embodiment. FIG. 13 is a graph showing transfer characteristics of a thin film transistor manufactured in the second embodiment. FIG. 10 is a diagram of transfer characteristics of a thin film transistor manufactured in a third embodiment. FIG. 10 is a diagram of transfer characteristics of a thin film transistor manufactured in a fourth embodiment. The figure of the current-voltage characteristic of the diode produced in 5th Embodiment.

Embodiments of the present invention will be described below.

In the embodiment of the present invention, a metal oxide thin film is pressurized under certain conditions and a process for promoting the formation of a metal oxide by a photochemical reaction by irradiating ultraviolet light to a coating film made of a metal compound. By applying the process, a thin film element having a high electronic function can be manufactured. In order to be able to use a general-purpose plastic film having a heat resistance temperature of 200 ° C. or less that is inexpensive and has a large distribution amount as a substrate, all of the coating process such as low-temperature printing, the ultraviolet light irradiation process, and the pressurization process are performed at 200 ° C. It is desirable to carry out the following. In addition, when using a heat resistant thing as a base material, although it is not necessary to limit to 200 degrees or less, it is possible to implement at lower temperature than before.

In the manufacturing apparatus according to the embodiment of the present invention, the pressure at the time of pressurization greatly affects the electrical performance of the oxide thin film to be manufactured. Therefore, in order to pressurize at an appropriate pressure, the necessary pressure is controlled or measured. It is preferable to provide an apparatus.

In the embodiment of the present invention, oxygen gas, ozone gas, carbon monoxide gas, carbon dioxide gas, hydrogen peroxide gas, nitrogen monoxide gas, nitrogen dioxide gas, subnitridation are used as the gas species constituting the controlled gas atmosphere. Oxygen gas and other gases used to form metal oxides, and raw gases that generate atomic oxygen species, as well as impurities for adjusting the concentration of source gases such as hydrogen gas, nitrogen gas, ammonia gas, and argon gas. An active gas and a reactive gas for promoting a chemical reaction may be mentioned. By introducing these gas species, the performance and productivity of the thin film can be controlled.

In the embodiment of the present invention, oxygen, hydrogen, nitrogen, ozone, ammonia, carbon monoxide, carbon dioxide, peroxidation are used as a medium for uniformly pressurizing the metal oxide thin film at 200 degrees or less. Gas such as hydrogen, nitric oxide, nitrogen dioxide, nitrous oxide, argon, or liquid such as water, alkane, alcohol, ketone, ether, aldehyde, carboxylic acid, amine, sulfonic acid, aliphatic organic compound More preferably, or both are introduced into the production apparatus.

The metal oxide thin film constituting the electrode layer or the semiconductor layer manufactured in the embodiment of the present invention includes a photoconversion reaction for forming an oxide from a coating film containing a metal compound produced by a coating process, It is obtained by a process with pressurization for densifying the metal oxide thin film.

Examples of the oxide thin film element of the present invention include those composed of conductive or semiconductor amorphous oxides containing at least one metal element of In, Ga, Zn, Ni, Cu, and Sn. Moreover, elements other than these may be contained by doping or metal substitution.

The amorphous metal oxide thin film produced according to the embodiment of the present invention is obtained by applying a thin film by applying a solution containing a metal compound onto a substrate and converting the thin film. The substrate used is not particularly limited, and any substrate may be used. Suitable materials are polycarbonate, polyetherimide, polyimide, polyethylene terephthalate (PET), polyethylene naphthalate, polypropylene, polyphenylene sulfide, polyether ether ketone, polyether ketone, polyether sulfone, polysulfone, polyphenylene sulfide, poly Although it is a flexible plastic substrate such as arylate or polyaramid, a glass, metal, or ceramic substrate may be used. Alternatively, a crystal substrate such as silicon, gallium nitride, gallium arsenide, or gallium phosphide can be used. At this time, in order to stabilize the device, extend the life, and improve the workability of the sealing thin film formed thereon, the device is composed of a mixture or lamination of a plurality of materials or subjected to a surface treatment. It is also possible.

In the production method or apparatus of the present invention, the substrate on which the metal oxide thin film is formed is cleaned or cleaned to improve the physical and electrical performance of the thin film and the adhesion of the coating film. It is desirable to remove impurities. There is no particular limitation on the method. Methods for cleaning or removing impurities include immersion cleaning with clean water, organic chemicals, acidic chemicals, alkaline chemicals or a mixture of these, flow cleaning, ultrasonic cleaning, and steam generated from the chemicals. Contact cleaning with ozone gas and active gas species (molecules, ions, radicals, plasma, etc.) composed of various elements, methods of removing impurities by impinging inert chemical species such as argon and xenon on the substrate surface, laser And a method of removing impurities by irradiating various energy rays.

Before applying a solution containing a metal compound to a substrate, a step of controlling surface properties such as repellency of the coated surface by applying or adsorbing a surface active substance or the like is provided. Adhesiveness to the substrate, surface smoothness, and the like can be improved, and a thin film element having excellent mechanical and electrical performance can be obtained.

In the embodiment of the present invention, the amorphous oxide thin film is obtained by producing the original thin film by a process of applying a metal compound as a raw material on the substrate and converting it, but the application at this time There is no limitation in particular as a method (it is also called the coating method). Examples of the methods used include spin coating, dip coating, cast coating, spray coating, blade coating, ink jet, transfer, and letterpress printing, stencil printing, offset printing, gravure printing, and reversal printing. Printing method, etc.

In the embodiment of the present invention, a thin film made of a metal compound is formed by a coating method. A solvent used in the coating method is an inorganic liquid such as water, an acidic aqueous solution, an alkaline aqueous solution, an aromatic hydrocarbon, a fat. Organic liquids such as aromatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, halogenated aromatic hydrocarbons, ethers and amines can be used. The solvent used in the coating method is used as a mixed solvent containing a single component or two or more of the above solvents. In particular, by using a mixed solvent containing two or more solvents with different physical properties such as thermal properties such as boiling point and volatility and solubility in metal compounds, a high degree of uniformity can be achieved by controlling the drying process of the coating film. And high quality of the thin film such as no defect can be imparted.

The thickness of the film on which the metal compound thin film used in the embodiment of the present invention is applied once on the substrate is 5 nm or more and 10 μm or less, preferably 10 nm or more and 1 μm or less.

In order to produce a thin film having a sufficient film thickness desired in the present invention, the coating process of the metal compound as the precursor can be performed a plurality of times. In that case, it is also possible to perform the above-mentioned washing and degassing steps before and after the coating step. In addition, when performing the coating process a plurality of times, thin films of different compounds can be laminated and applied.

The metal compound thin film used in the embodiment of the present invention may be provided with a step of removing a part or all of the solvent by heating the thin film after coating film formation. Although the heating apparatus used here is not particularly limited, a resistance heating apparatus, an infrared heating apparatus, or the like is used. The temperature atmosphere for heating varies depending on the solvent used, but the heating temperature is preferably 20 ° C. or more and 150 ° C. or less. A method of irradiating a coating film with a relatively low energy laser beam or various energy rays for the purpose of removing the solvent is also possible. The atmosphere in which the metal compound that serves as a precursor for heating is placed is desirably an atmospheric pressure atmosphere. Further, the time required for removing the heated solvent at this time is not particularly limited. Although it is about 1 second or more and 180 minutes or less, it is preferably 10 seconds to 3 minutes.

The base material coated with the metal compound thin film is carried into the reaction part for performing ultraviolet light irradiation and / or pressurization treatment while being kept at a temperature under a controlled gas atmosphere. There is no particular limitation on the means for carrying in at this time. It is also possible to move the inside of the reaction section at a certain speed in order to continuously produce a thin film element. In addition, it is desirable to be able to control the atmosphere to be transported for the purpose of preventing the applied metal compound from being altered by oxygen, moisture, or temperature in the atmosphere.

In the production apparatus of the embodiment of the present invention, the gas composition and temperature inside the reaction part for producing a metal oxide thin film by simultaneous or sequential treatment of ultraviolet light irradiation and pressurization of a coating film made of a metal compound are appropriately set. It is desirable to be able to control under various conditions. An apparatus for performing ultraviolet light irradiation and pressurization simultaneously is shown in FIG. 1, and an apparatus for performing ultraviolet light irradiation and pressurization by sequential processing is shown in FIG. The structure of each device will be described later in each embodiment.

In the manufacturing apparatus according to the embodiment of the present invention, when an oxide thin film element is manufactured, an inert gas such as nitrogen or argon that does not contain oxygen atoms is added to a part of the gas inside the reaction part, thereby By adjusting the reaction gas concentration and the intensity of ultraviolet light irradiation from the ultraviolet lamp, it is possible to control the film formability and reaction rate of the oxide thin film. Alternatively, by introducing a gas acting as a catalyst for the conversion reaction such as ammonia or hydrogen, effects such as acceleration of the reaction and improvement of the film quality can be obtained.

In order to convert the metal compound thin film used in the present invention into an oxide thin film, ultraviolet rays are irradiated to an atmospheric gas containing oxygen chemical species, but the above-mentioned energy rays are directly irradiated to the metal compound thin film. Metal oxides also by a reaction mechanism that promotes the conversion reaction to metal oxides by easily reacting with oxygen species in the atmosphere by decomposing chemical bonds of metal compounds in the thin film and activating the metal compounds A thin film can be obtained.

In the manufacturing apparatus in the embodiment of the present invention, the wavelength of ultraviolet light when irradiating ultraviolet light in an atmosphere containing a coating film or oxygen chemical species activates oxygen in the atmosphere or a metal compound in the thin film. It is necessary to have the necessary energy. The wavelength of ultraviolet light necessary to achieve this purpose is 240 nm or less. Light having such a wavelength can be obtained by an excimer laser or the like in addition to a deuterium lamp, a xenon lamp, an excimer lamp, a mercury lamp, or the like.

In the embodiment of the present invention, when irradiating ultraviolet light in an atmosphere containing oxygen chemical species in order to convert the metal compound thin film into a metal oxide thin film, the irradiation light quantity per unit time and unit area of the irradiated ultraviolet light The higher the is, the higher the conversion efficiency to the metal oxide, but the same effect can be obtained by irradiating ultraviolet light with a small amount of light for a long time. Therefore, the minimum necessary unit time of irradiation with ultraviolet light and irradiation energy per unit area are not particularly limited. Further, it is not always necessary to irradiate the ultraviolet light continuously, and it may be intermittent light irradiation or light irradiation by a pulse light source.

In the embodiment of the present invention, a liquid obtained by dissolving a metal compound containing at least one metal element among In, Zn, Ga, Sn, Cu, and Ni in a solvent is used as a coating raw material, and this is applied to the substrate. By applying, an elementary thin film is formed, and by converting it, it is formed as a conductor or semiconductor thin film made of a metal oxide. The process temperature at the time of conversion is about 0 ° C. or more and about 200 ° C. or less, but a metal oxide thin film having better electrical properties can be obtained at a higher temperature if it is not higher than the heat resistance temperature of the substrate. Further, the time required for the conversion reaction at this time is not particularly limited. Generally, it is 1 minute or more and 720 minutes or less, but 5 minutes to 120 minutes is preferable.

In the embodiment of the present invention, a thin film having required electrical performance is manufactured by increasing the compactness of the film by pressurizing and baking the thin film. If the pressure is within the range that the substrate can withstand, a metal oxide thin film with higher electrical properties can be obtained at higher values. Further, the time required for pressurization at this time is not particularly limited. Generally, it is 1 minute or more and 720 minutes or less, but 5 minutes to 120 minutes is preferable. Even if the applied pressure is not sufficiently high, it is possible to make a dense thin film similar to the case where a high pressure is applied by extending the pressurization time.

In the embodiment of the present invention, the conversion reaction when converting a thin film made of a metal compound into a thin film of a conductor or semiconductor made of a metal oxide is performed once or more, so that the thin film element having a finally required thickness is obtained. Can be obtained.

(First embodiment)
This embodiment will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of the thin film manufacturing apparatus of the present embodiment. This apparatus is used, for example, to form a metal oxide thin film used as an electrode layer or a semiconductor layer in the process of manufacturing a thin film transistor element on a flexible plastic substrate. The apparatus shown in FIG. 1 includes a pressure-resistant reaction chamber 10 for forming a coating film made of a metal compound on a base material made of a plastic sheet, a glass plate, etc., and then converting it to an electrode layer or a semiconductor layer made of a metal oxide. On the other hand, an ultraviolet lamp device 20 for irradiating ultraviolet light from directly above, a pressure sensor 30 for measuring the pressure in the pressure resistant reaction chamber 10, and atmospheric gas and pressurization in the pressure resistant reaction chamber 10. A gas introduction pipe 40 for introducing the medium, an introduction gas control valve 50 for controlling the gas introduction amount, a gas discharge pipe 60 for discharging the atmospheric gas and the pressurized medium, and a gas discharge amount are controlled. An exhaust gas control valve 70, a substrate with a thin film 80, and a substrate support 90 are provided. FIG. 1 shows the concept of the arrangement of the apparatus according to the present embodiment. Information regarding the pressure in the pressure-resistant reaction chamber 10 detected by the pressure sensor 30 is automatically transmitted to the control valve by an electric signal, or a person who operates the apparatus using the displayed information manually operates the control valve. By doing so, it is possible to control the pressure in the reaction chamber. Although not shown in the figure, the pressure-resistant reaction chamber or the substrate support is provided with a heating means for maintaining the substrate and the thin film on the substrate at a desired temperature of room temperature to 200 degrees C. When the temperature of the base material rises to a desired temperature or higher due to ultraviolet light irradiation, a temperature holding device having means for cooling the base material is provided. Although not shown in the figure, means for measuring the substrate temperature, means for evacuating the reaction part, and the like are provided.

In the present embodiment, the coating film formed by coating a solution containing a metal compound serving as a metal oxide precursor is irradiated with ultraviolet rays in a gas atmosphere, and the coating film is normally used. The case where the step of pressurizing at a pressure equal to or higher than the pressure is simultaneously performed to manufacture a conductor or semiconductor oxide thin film element made of a metal oxide will be specifically described.

Zinc acetate (II) and indium acetate (III) were dissolved in 2-methoxyethanol to prepare a solution having a concentration of 1M. To this was added 2-ethanolamine and acetic acid to obtain a raw material solution for producing a coated thin film. A mirror-polished silicon wafer having a thickness of 0.2 mm was used as a substrate for forming a thin film. A silicon oxide film having a thickness of about 300 nm is formed on the wafer surface by a thermal oxidation method. The substrate was a substrate from which dust and organic substances attached to the surface were removed using a chemical solution or the like. After the raw material solution is applied to the entire surface of the substrate, and then the solvent is removed by heating and drying, the substrate is immediately placed on a support stand arranged immediately below the ultraviolet lamp provided in the pressure resistant reaction chamber of the manufacturing apparatus of FIG. Put it on.

In order to control the gas atmosphere in the reaction part, a mixed gas of nitrogen and oxygen through a desiccant was introduced from the gas inlet. With the atmosphere gas around the thin film sufficiently filled with the mixed gas and the pressure in the reaction chamber reached 0.7 MPa, the thin film on the substrate was irradiated with ultraviolet light using an ultraviolet lamp. At the same time, the substrate support was heated to heat the coating film on the substrate. The temperature of the thin film on the substrate was maintained at 200 ° C. using a temperature control device provided on the support base. After maintaining this state for 120 minutes, the ultraviolet lamp and the temperature control device were stopped. Immediately, the gas in the reaction chamber was quickly discharged from the discharge tube and returned to normal pressure, and then the substrate was taken out of the reaction chamber to obtain a thin film element.

The thickness of the prepared composite oxide thin film of indium and zinc was about 50 nm. FIG. 3 shows an FT-IR pattern spectrum of the produced thin film. In the spectrum, the absorption peak at 1600 cm ⁻¹ derived from the bond between carbon and oxygen that appeared in the raw material thin film disappeared, and the absorption at 1100 cm ⁻¹ derived from the bond between metal and oxygen appeared, and thus the coating film It turns out that the metal compound in it has converted into the metal oxide. Source and drain electrodes were produced by mask vapor deposition of aluminum on the oxide thin film, and a thin film transistor having a metal oxide thin film as a semiconductor channel layer was produced. FIG. 4 shows the evaluation results of the electrical characteristics of the manufactured thin film transistor. In FIG. 4, the horizontal axis represents the gate voltage, the left vertical axis represents the current value Ids flowing between the source and the drain, and the right represents the square root of the current value. It was found that excellent electrical characteristics as shown in FIG. 4 were exhibited. From FIG. 4, the carrier mobility of the transistor was 0.002 cm ² / Vs, and the threshold voltage was −3V.

(Second Embodiment)
This embodiment will be described below with reference to the drawings. FIG. 2 is a conceptual diagram of the thin film manufacturing apparatus of the present embodiment. This apparatus forms a coating film made of a metal compound on a substrate made of a plastic sheet, a glass plate or the like, and then converts it into an electrode layer or a semiconductor layer made of a metal oxide, and the coating film An ultraviolet lamp device 20 for irradiating ultraviolet light from directly above, a pressure sensor 30 for measuring the pressure in the pressure-resistant reaction chamber 10, and a gas introduction for introducing an atmospheric gas or a medium for pressurization A pipe 40, an introduction gas control valve 50 for controlling the gas introduction amount, a gas discharge pipe 60 for discharging the atmospheric gas or the pressurized medium, an exhaust gas control valve 70 for controlling the gas discharge amount, and a thin film And an attached substrate 80. This apparatus is independent of an ultraviolet lamp apparatus 20 that irradiates a film on a substrate with ultraviolet light from directly above and an apparatus that applies a controlled pressure higher than normal pressure to a thin film or a substrate including a thin film. And a base material transport device 100 for moving the base material between the two devices. The pressure-resistant reaction chamber 10 is provided with a substrate transfer port 110 through which the substrate transfer device passes during transfer. Although not shown in the drawing, the pressure-resistant reaction chamber 10 or the substrate transfer apparatus 100 has a heating means for maintaining the substrate and the thin film on the substrate at a desired temperature of room temperature to 200 degrees C. In the case where the temperature of the substrate rises to a desired temperature or higher due to light irradiation, a temperature holding device having means for cooling the substrate is provided. Although not shown in the figure, means for measuring the substrate temperature, means for evacuating the reaction part, and the like are provided. Furthermore, although not shown in the drawing, it is possible to efficiently produce an oxide thin film by providing a means for the substrate transfer apparatus to control the atmospheric gas during substrate transfer.

In the present embodiment, the coating film formed by coating a solution containing a metal compound serving as a metal oxide precursor is irradiated with ultraviolet rays in a gas atmosphere, and the coating film is normally used. The case where a conductor or semiconductor oxide thin film element made of a metal oxide is manufactured by sequentially performing the pressurization with a pressure equal to or higher than the pressure will be specifically described.

Zinc acetate (II) and indium acetate (III) were dissolved in 2-methoxyethanol to prepare a solution having a concentration of 1M. To this was added 2-ethanolamine and acetic acid to obtain a raw material solution for producing a coated thin film. A mirror-polished silicon wafer having a thickness of 0.2 mm was used as a substrate for forming a thin film. A silicon oxide film having a thickness of about 300 nm is formed on the wafer surface by a thermal oxidation method. The substrate was a substrate from which dust and organic substances attached to the surface were removed using a chemical solution or the like. The raw material solution was applied onto the entire surface of the substrate, and then the solvent was removed by heating and drying, and then immediately placed on a transport device disposed immediately below the ultraviolet lamp provided in the manufacturing apparatus of FIG.

The thin film on the substrate was irradiated with ultraviolet light for 60 minutes using an ultraviolet lamp while maintaining the temperature of the thin film at 200 ° C. using a temperature controller under normal pressure. After irradiation, the substrate with the thin film is introduced into the pressure-resistant reaction chamber while maintaining the thin film temperature at 200 ° C., and the chamber is pressurized to 0.7 MPa for 60 minutes using the substrate transfer apparatus (200). Degree). Thereafter, the pressure-resistant reaction chamber was returned to normal pressure, and the substrate was taken out of the pressure-resistant reaction chamber to obtain a thin film element.

The thickness of the prepared composite oxide thin film of indium and zinc was about 50 nm. Source and drain electrodes were produced by mask vapor deposition of aluminum on the obtained oxide thin film, and a thin film transistor having a metal oxide thin film as a semiconductor channel layer was produced. FIG. 5 shows an evaluation result of electrical characteristics of the manufactured thin film transistor. It was found that excellent electrical characteristics as shown in FIG. 5 were exhibited. From FIG. 5, the carrier mobility of the transistor was 0.024 cm ² / Vs.

(Third embodiment)
In this embodiment, the case where the metal oxide is a composite oxide of zinc, indium, and tin is specifically described. In the present embodiment, a step of irradiating ultraviolet rays in a gas atmosphere with respect to a coating film formed by coating a solution containing a metal compound of zinc, indium and tin, which is a precursor of a metal oxide, A step of pressurizing the coating film at a pressure equal to or higher than normal pressure was sequentially performed to manufacture a conductor or semiconductor oxide thin film element made of a metal oxide.

Zinc acetate (II), indium acetate (III) and tin acetate (II) were dissolved in 2-methoxyethanol to prepare a solution having a concentration of 1M. To this was added 2-ethanolamine and acetic acid to obtain a raw material solution for producing a coated thin film. A mirror-polished silicon wafer having a thickness of 0.2 mm was used as a substrate for forming a thin film. A silicon oxide film having a thickness of about 300 nm is formed on the wafer surface by a thermal oxidation method. The substrate was a substrate from which dust and organic substances attached to the surface were removed using a chemical solution or the like. The raw material solution was applied onto the entire surface of the substrate, and then the solvent was removed by heating and drying, and then immediately placed on a transport device disposed immediately below the ultraviolet lamp provided in the manufacturing apparatus of FIG.

The thin film on the substrate was irradiated with ultraviolet light for 60 minutes using an ultraviolet lamp while maintaining the temperature of the thin film at 200 ° C. using a temperature controller under normal pressure. After the irradiation, using a substrate transfer device, the substrate with the thin film was introduced into the pressure resistant reaction chamber while maintaining the thin film temperature at 200 ° C., and subjected to pressure heat treatment for 60 minutes while the reaction chamber was pressurized to 0.7 MPa. It was. Thereafter, the reaction chamber was returned to normal pressure, and the substrate was taken out of the pressure-resistant reaction chamber to obtain a thin film element.

The thickness of the produced indium, zinc and tin composite oxide thin film was about 50 nm. Source and drain electrodes were produced by mask vapor deposition of aluminum on the obtained oxide thin film, and a thin film transistor having a metal oxide thin film as a semiconductor channel layer was produced. FIG. 6 shows an evaluation result of electrical characteristics of the manufactured thin film transistor. It turned out that the outstanding electrical property as shown in FIG. 6 is shown. From FIG. 6, the carrier mobility of the transistor was 0.01-0.026 cm ² / Vs.

(Fourth embodiment)
In the present embodiment, the pressure was applied differently from that in the second embodiment.
Zinc (II) acetate and indium (III) acetate were dissolved in 2-methoxyethanol to prepare a solution having a concentration of 1M. To this was added 2-ethanolamine and acetic acid to obtain a raw material solution for producing a coated thin film. A mirror-polished silicon wafer having a thickness of 0.2 mm was used as a substrate for forming a thin film. A silicon oxide film having a thickness of about 300 nm is formed on the wafer surface by a thermal oxidation method. The substrate was a substrate from which dust and organic substances attached to the surface were removed using a chemical solution or the like. The raw material solution was applied onto the entire surface of the substrate, and then the solvent was removed by heating and drying, and then immediately placed on a transport device disposed immediately below the ultraviolet lamp provided in the manufacturing apparatus of FIG.

The thin film on the substrate was irradiated with ultraviolet light for 60 minutes using an ultraviolet lamp while maintaining the temperature of the thin film at 200 ° C. using a temperature controller under normal pressure. After irradiation, the substrate with thin film is introduced into the pressure-resistant reaction chamber while maintaining the thin film temperature at 200 ° C., and heated under pressure for 60 minutes while the pressure-resistant reaction chamber is pressurized to 0.6 MPa. Processing (200 degrees) was performed. Thereafter, the pressure-resistant reaction chamber was returned to normal pressure, and the substrate was taken out of the pressure-resistant reaction chamber to obtain a thin film element.

The thickness of the prepared composite oxide thin film of indium and zinc was about 50 nm. Source and drain electrodes were produced by mask vapor deposition of aluminum on the obtained oxide thin film, and a thin film transistor having a metal oxide thin film as a semiconductor channel layer was produced. FIG. 7 shows an evaluation result of electrical characteristics of the manufactured thin film transistor. It was found that excellent electrical characteristics as shown in FIG. 7 were exhibited. From FIG. 7, the carrier mobility of the transistor was 0.047 cm ² / Vs.

(Fifth embodiment)
In this embodiment, a film substrate is used as the substrate. In addition, a diode was manufactured by carrying out in a pressurized state different from that in the second embodiment.

Zinc acetate (II) and indium acetate (III) were dissolved in 2-methoxyethanol to prepare a solution having a concentration of 1M. To this was added 2-ethanolamine and acetic acid to obtain a raw material solution for producing a coated thin film. A polyimide film having a thickness of 0.05 mm was used as a substrate for forming a thin film. The film substrate used was a product from which dust and organic substances adhering to the surface were removed using a chemical solution or the like. The raw material solution was applied onto the entire surface of the substrate, and then the solvent was removed by heating and drying, and then immediately placed on a transport device disposed immediately below the ultraviolet lamp provided in the manufacturing apparatus of FIG.

The thin film on the substrate was irradiated with ultraviolet light for 60 minutes using an ultraviolet lamp while maintaining the temperature of the thin film at 200 ° C. using a temperature controller under normal pressure. After irradiation, the substrate with the thin film was introduced into the pressure-resistant reaction chamber while maintaining the thin film temperature at 200 ° C. using a substrate transfer device, and pressurized and heated for 60 minutes in a state where the reaction chamber was pressurized to 0.75 MPa (200 Degree). Thereafter, the pressure-resistant reaction chamber was returned to normal pressure, and the substrate was taken out of the pressure-resistant reaction chamber to obtain a thin film element.

The thickness of the produced indium and zinc composite oxide thin film was about 200 nm. A two-terminal electrode was prepared by vapor-depositing aluminum on the obtained oxide thin film, and a diode having a metal oxide thin film sandwiched between the electrodes was produced. FIG. 8 shows the measurement results of the current-voltage characteristics of the manufactured diode. As shown in FIG. 8, it was confirmed that the produced thin film was a semiconductor thin film because it showed rectification characteristics.

(Comparative Example 1)
In order to explain the effect of the present invention, a comparative example is shown in which treatment is performed under a predetermined pressure without irradiating ultraviolet light.

Zinc acetate (II) and indium acetate (III) were dissolved in 2-methoxyethanol to prepare a solution having a concentration of 1M. To this was added 2-ethanolamine and acetic acid to obtain a raw material solution for producing a coated thin film. A mirror-polished silicon wafer having a thickness of 0.2 mm was used as a substrate for forming a thin film. A silicon oxide film having a thickness of about 300 nm is formed on the wafer surface by a thermal oxidation method. The substrate was a substrate from which dust and organic substances attached to the surface were removed using a chemical solution or the like. The raw material solution was applied to the entire surface of the substrate, and then the solvent was removed by heating and drying, and then immediately placed on the support of the pressure resistant reaction chamber of the manufacturing apparatus of FIG.

The pressure heat treatment (200 degree | times) was performed for 120 minutes in the state pressurized to 0.7 Mpa in the pressure-resistant reaction chamber. Thereafter, the pressure-resistant reaction chamber was returned to normal pressure, and the substrate was taken out of the pressure-resistant reaction chamber to obtain a thin film element.

The thickness of the produced indium and zinc composite oxide thin film was about 50 nm. Thin film transistors in which source and drain electrodes are formed so as to have the same structure as in the first embodiment by depositing aluminum on the obtained oxide thin film as a mask, and the metal oxide thin film is a semiconductor channel layer A device structure was fabricated. However, when the electrical characteristics of the device were evaluated, the value of the current flowing between SD at the SD voltage +40 V and the gate voltage +40 V was 0.1 nA or less, and the thin film transistor device did not have a function.

(Comparative Example 2)
In order to explain the effect of the present invention, a comparative example is shown in which only heating under ultraviolet light irradiation is performed and no pressure heat treatment is performed.

Zinc acetate (II) and indium acetate (III) were dissolved in 2-methoxyethanol to prepare a solution having a concentration of 1M. To this was added 2-ethanolamine and acetic acid to obtain a raw material solution for producing a coated thin film. A mirror-polished silicon wafer having a thickness of 0.2 mm was used as a substrate for forming a thin film. A silicon oxide film having a thickness of about 300 nm is formed on the wafer surface by a thermal oxidation method. The substrate was a substrate from which dust and organic substances attached to the surface were removed using a chemical solution or the like. The raw material solution was applied to the entire surface of the substrate, and then the solvent was removed by heating and drying, and then immediately placed on the support of the pressure resistant reaction chamber of the manufacturing apparatus of FIG.

The thin film on the substrate was irradiated with ultraviolet light for 120 minutes using an ultraviolet lamp while maintaining the temperature of the thin film at 200 ° C. using a temperature controller under normal pressure. Thereafter, the substrate was taken out to obtain a thin film element.

The thickness of the produced indium and zinc composite oxide thin film was about 50 nm. Thin film transistors in which source and drain electrodes are formed so as to have the same structure as in the first embodiment by depositing aluminum on the obtained oxide thin film as a mask, and the metal oxide thin film is a semiconductor channel layer The structure of was produced. However, when the electrical characteristics of the device were evaluated, the field effect due to the application of the gate voltage was not exhibited, and therefore it was confirmed that the oxide thin film produced in this comparative example was not converted into a semiconductor thin film.

(Sixth embodiment)
In the present embodiment, the pressurizing condition was examined.
Zinc (II) acetate and indium (III) acetate were dissolved in 2-methoxyethanol to prepare a solution having a concentration of 1M. To this was added 2-ethanolamine and acetic acid to obtain a raw material solution for producing a coated thin film. A mirror-polished silicon wafer having a thickness of 0.2 mm was used as a substrate for forming a thin film. A silicon oxide film having a thickness of about 300 nm is formed on the wafer surface by a thermal oxidation method. The substrate was a substrate from which dust and organic substances attached to the surface were removed using a chemical solution or the like. The raw material solution was applied onto the entire surface of the substrate, and then the solvent was removed by heating and drying, and then immediately placed on a transport device disposed immediately below the ultraviolet lamp provided in the manufacturing apparatus of FIG.

The thin film on the substrate was irradiated with ultraviolet light for 60 minutes using an ultraviolet lamp while maintaining the temperature of the thin film at 200 ° C. using a temperature controller under normal pressure. After irradiation, the substrate is transferred to the pressure-resistant reaction chamber while maintaining the thin film temperature at 200 ° C. using a substrate transfer device, and the pressure-resistant reaction chamber is pressurized to a predetermined value P (0.1 to 0.7 MPa). A pressure heat treatment was performed for a minute. Thereafter, the pressure-resistant reaction chamber was returned to normal pressure, and the substrate was taken out of the pressure-resistant reaction chamber to obtain a thin film element.

The thickness of the produced indium and zinc composite oxide thin film was about 50 nm. Source and drain electrodes were produced by mask vapor deposition of aluminum on the obtained oxide thin film, and a thin film transistor element structure having a metal oxide thin film as a semiconductor channel layer was produced. The electrical characteristics of the fabricated device were evaluated. When the predetermined pressure value P was 0.5 MPa, the value of the current flowing between the SD at an SD voltage of +40 V and a gate voltage of +40 V was 0.01 nA or less and did not function as a semiconductor thin film. Table 1 shows whether or not an oxide semiconductor thin film can be formed when the pressure in the pressure-resistant reaction chamber is varied.

According to Table 1, it can be seen that an oxide semiconductor thin film is formed when the heat treatment is performed under pressure in a pressure resistant reaction chamber pressure of 0.6 or more. In addition, Table 1 above is a case where the experimental conditions were performed at a heating temperature of 200 ° C. and a total reaction time of 120 minutes in all steps. Conversion to a semiconductor thin film can be expected even under pressurized conditions.

The examples shown in the above embodiment and the like are described for easy understanding of the invention, and are not limited to this embodiment.

According to the manufacturing method and manufacturing apparatus of the present invention, electrical properties, reliability, and durability equivalent to those used in the electronic industry by a coating process on a flexible plastic substrate with low heat resistance are provided. Since a semiconductor element can be produced, it is possible to make a film element, an area, and a flexible element as well as simplifying and saving energy in the manufacturing process. As a result, it can be used for mass production of electronic devices such as electronic tags, electronic posters, and electronic papers that are highly demanded of impact resistance, weather resistance, portability, low cost, etc., and is industrially useful.

DESCRIPTION OF SYMBOLS 10 Pressure-resistant reaction chamber 20 Ultraviolet light lamp device 30 Pressure sensor 40 Gas introduction pipe 50 Introduction gas control valve 60 Gas exhaust pipe 70 Exhaust gas control valve 80 Substrate with a thin film 90 Substrate support stand 100 Substrate conveyance apparatus 110 Substrate conveyance port

Claims (10)

A method for producing a conductive oxide or semiconductor oxide thin film element comprising a metal oxide, wherein a gas is applied to a coating film formed by coating a solution containing a metal compound that is a precursor of the metal oxide. A method for producing an oxide thin film element, wherein the step of irradiating ultraviolet rays in an atmosphere and the step of pressurizing the coating film at a pressure equal to or higher than normal pressure are performed simultaneously or sequentially. The manufacturing method according to claim 1, wherein the pressure is 0.6 MPa or more. The manufacturing method according to claim 1, wherein the metal compound serving as the precursor includes one or more metals of In, Zn, Ga, Sn, Cu, and Ni. The manufacturing method according to claim 1, wherein the ultraviolet ray has a wavelength of 240 nm or less. 2. The manufacturing method according to claim 1, wherein, in the pressurizing step, a medium for pressurization is either a gas or a liquid introduced into the atmosphere, or both. The manufacturing method according to claim 1, wherein in the step of irradiating with ultraviolet rays, the coating film is held at a temperature of room temperature to 200 ° C. An oxide thin film element manufactured on the flexible substrate by the manufacturing method according to claim 1. An apparatus for manufacturing a conductive oxide or semiconductor oxide thin film element made of a metal oxide, wherein a gas is applied to a coating film formed by coating a solution containing a metal compound serving as a precursor of the metal oxide. An apparatus for producing an oxide thin film element, comprising: an apparatus for controlling the atmosphere to irradiate ultraviolet rays from an ultraviolet lamp; and an apparatus for pressurizing the coating film at a pressure equal to or higher than normal pressure. The manufacturing apparatus includes a pressure-resistant reaction chamber provided with the pressurizing device, an ultraviolet lamp that irradiates ultraviolet light directly on the coating film in the pressure-resistant reaction chamber, and a device that controls the pressure in the pressure-resistant reaction chamber. The manufacturing apparatus according to claim 8, further comprising: The manufacturing apparatus includes an ultraviolet lamp device unit that irradiates the coating film with ultraviolet light from directly above, a pressure-resistant reaction chamber including the device for pressurization, and the ultraviolet light lamp device unit and the pressure-resistant reaction chamber. The manufacturing apparatus according to claim 8, further comprising a transport device that transports the coating film between them.

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