JP6311594B2 - Organic transistor and manufacturing method thereof - Google Patents

Description

  The present invention relates to an organic transistor formed using a semiconductor thin film composed of an organic semiconductor material and the like, and a method for manufacturing such an organic transistor, and is suitable for application to organic EL (electroluminescence) and the like. .

  As a general organic transistor of this type, a gate electrode and a gate insulating film that covers the gate electrode are formed on an insulating substrate, and a source electrode and a drain electrode that are separated from each other via the gate insulating film on the gate electrode In which an organic semiconductor layer is formed on the surface of the gate insulating film so as to connect the source electrode and the drain electrode (see, for example, Patent Document 1).

  Here, conventionally, as the gate insulating film, a general inorganic metal oxide film such as alumina, or a polymer insulating layer described in Patent Document 1 and an inorganic film thereon is employed. Yes.

JP 2009-194208 A

  By the way, when the gate insulating film is made of an inorganic metal oxide film as in the prior art, high mobility and low driving voltage in the organic transistor can be ensured, but since the stress of the film is large, the warping of the substrate It is not preferable for the suppression. In the case of Patent Document 1, since the polymer insulating layer has a low dielectric constant, it is difficult to realize a low driving voltage.

  In view of such circumstances, the present inventor has examined the use of an organic metal mixed layer as a gate insulating film. The organic metal mixed layer is formed by laminating an inorganic metal oxide film such as alumina and an organic metal film such as Alcon.

  When such an organic metal mixed layer is used as the gate insulating film, the driving voltage (gate driving voltage) can be reduced because of the high dielectric constant. In addition, since the stress of the film is small, the suppression of the warpage of the substrate is also good.

  However, according to further studies by the present inventors, the outermost surface on the organic semiconductor layer side in this organic metal mixed layer, that is, the base of the organic semiconductor layer is an inorganic metal oxide film, and an organic metal film. It turns out that each has its own problems.

  First, when the outermost surface of the organometallic mixed layer is an organometallic film, a low driving voltage is secured. However, since the contact angle is high in the organic metal film, the crystallinity of the organic semiconductor layer is disturbed, and the mobility of the organic transistor is easily lowered. On the other hand, when the outermost surface of the organic metal mixed layer is an inorganic metal oxide film, both low driving voltage and high mobility are ensured. However, in this case, a problem occurs in the water resistance of the membrane.

  Typically, the organometallic film is formed by molecular layer deposition (MLD), and the metal oxide film is formed by atomic layer deposition (ALD). Therefore, a water cleaning step of cleaning the substrate with water in order to remove residues generated during the patterning after forming the gate insulating film as the organic metal mixed layer by MLD or ALD, that is, during etching. Need to do. Then, in this water cleaning process, water contacts the surface of the gate insulating film. The difficulty in dissolving the film in water is water resistance.

  Therefore, water resistance is required for the outermost surface of the gate insulating film. However, when the outermost surface of the organic metal mixed layer is an inorganic metal oxide film, there is a problem that the film dissolves in water, that is, a so-called film reduction problem. I found it to happen. On the other hand, when the outermost surface of the organic metal mixed layer is an organic metal film, water resistance is ensured.

  The present invention has been made in view of the above problems, and in an organic transistor using an organic metal mixed layer capable of securing a low driving voltage as a gate insulating film, it achieves both water resistance and high mobility in the organic transistor. The object is to realize a configuration suitable for the above.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a substrate (10), a gate electrode (20) formed on the substrate, and a gate insulating film (30) covering the gate electrode on the substrate. And a source electrode (50) and a drain electrode (60) which are spaced apart from each other via a gate insulating film on the gate electrode, and at least between the source electrode and the drain electrode on the surface of the gate insulating film An organic semiconductor layer (40) formed so as to connect the gate insulating film, and the gate insulating film is formed by laminating the organic metal films (31a, 31) and the inorganic metal oxide film (32). The outermost surface on the semiconductor layer side is an organometallic film, and only the surface layer portion in the film thickness direction of the outermost organometallic film (31a) is an inorganic metal oxide layer (31b) formed by modification. Tosa And wherein the are.

  In the water cleaning process, when the outermost surface of the gate insulating film is an inorganic metal oxide film, it is sufficient that the film is not reduced due to the dissolution of the film. In the water cleaning step, dirt and the like after film formation are cleaned and removed. Therefore, as the gate insulating film, all films are formed, that is, the outermost organometallic film is formed. If it is in a filmed state, a water washing step can be performed.

  That is, the water washing process may be performed on the gate insulating film in a state where the laminated structure is formed but before the surface layer portion of the outermost organometallic film is modified. According to this, film loss is prevented by the organic metal film having high water resistance.

  Then, after the water washing step, if the surface layer portion of the outermost organometallic film is modified to form an inorganic metal oxide layer, the inorganic metal oxide layer that is desirable in terms of securing the mobility will eventually become the organic semiconductor layer. A gate insulating film serving as a base is formed.

  Thus, according to the present invention, it is possible to realize a configuration suitable for achieving both water resistance and high mobility in the organic transistor.

  Here, if the outermost organometallic film is too thick, only the surface layer portion of the entire outermost organometallic film is modified to form an inorganic metal oxide layer, and the organometallic portion of the inner layer portion remains thick, The characteristics of the organic metal film as a whole tend to be strong. Due to the roughness of the organic metal film, when the organic metal film is used as the base of the organic semiconductor layer, the crystallinity of the organic semiconductor layer is disturbed and the mobility is likely to decrease. For this reason, the thickness of the outermost organometallic film is preferably less than 5 nm as in the invention described in claim 2.

  The invention according to claim 5 is a step of preparing a substrate (10), a step of forming a gate electrode (20) on the substrate, and a gate insulating film (30) covering the gate electrode on the substrate. A step of forming an organic semiconductor layer (40) on the gate insulating film, and a source electrode (50) and a drain electrode (60) in contact with the organic semiconductor layer on the gate insulating film while overlapping with the gate electrode. And a step of forming an organic transistor. The method of manufacturing an organic transistor further includes the following points.

  In the step of forming the gate insulating film, the organic metal films (31a, 31) and the inorganic metal oxide film (32) are laminated, and the outermost surface on the organic semiconductor layer side is the organic metal film (31a). A first step of forming a laminated film, and a second step after the first step, in which only the surface layer portion in the film thickness direction of the outermost organometallic film is modified to form an inorganic metal oxide layer (31b). It must be equipped with.

  A water washing step of washing the surface of the substrate including the outermost organometallic film with water between the first step and the second step in the step of forming the gate insulating film is performed. The manufacturing method of claim 5 is characterized by these points.

  According to this, although the water cleaning process is performed on the gate insulating film in a state before the surface layer portion of the outermost organometallic film is modified, the reduction of the film is prevented by the highly water-resistant organometallic film. . Then, after the water washing step, the surface layer portion of the organic metal film on the outermost surface is modified to form an inorganic metal oxide layer. Finally, the inorganic metal oxide layer desirable in terms of securing mobility is the organic semiconductor layer. A gate insulating film serving as a base is formed.

  Therefore, according to the present invention, it is possible to realize a configuration suitable for achieving both water resistance and high mobility in the organic transistor.

  In addition, the code | symbol in the bracket | parenthesis of each means described in the claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a schematic sectional drawing which shows the cross-sectional structure of the organic transistor concerning embodiment of this invention. It is an enlarged view which shows schematic structure of the A section enclosed with the circle in FIG. It is process drawing which shows the manufacturing method of the organic transistor concerning the said embodiment. It is process drawing which shows the manufacturing method of the organic transistor following FIG. It is a schematic sectional drawing which shows typically the mode of peeling of a gate insulating film.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, parts that are the same or equivalent to each other are given the same reference numerals in the drawings for the sake of simplicity.

  The configuration of the organic transistor according to the embodiment of the present invention will be described with reference to FIGS. This organic transistor is applied to, for example, a transistor provided in a drive circuit for an EL element.

  The organic transistor of this embodiment is configured by the structure shown in FIG. Specifically, a gate electrode 20 made of Cr (chromium) or the like is formed on a substrate 10 made of an insulating flexible substrate such as alkali-free glass, and covers the gate electrode 20. Thus, the gate insulating film 30 made of an insulating material is formed. The structure of the gate insulating film 30 is a feature of the present invention. The detailed structure of the gate insulating film 30 will be described later.

  An organic semiconductor layer 40 is formed on the gate insulating film 30. The organic semiconductor layer 40 is made of, for example, a thiophene organic semiconductor material (for example, C8-BTBT) and functions as a channel layer.

  A source electrode 50 and a drain electrode 60 are formed on the organic semiconductor layer 40. The source electrode 50 and the drain electrode 60 are disposed on both ends of the gate electrode 20 so as to be separated from each other via the gate insulating film 30 and the organic semiconductor layer 40.

  The organic semiconductor layer 40 is formed so as to connect the source electrode 50 and the drain electrode 60. The source electrode 50 and the drain electrode 60 are made of, for example, Au (gold). With such a structure, the organic transistor according to the present embodiment is configured.

  Next, the detailed structure of the gate insulating film 30 provided in the organic transistor configured as described above will be described.

  The gate insulating film 30 is composed of an organic metal mixed layer as a laminated film in which organic metal films 31 a and 31 and an inorganic metal oxide film 32 are laminated. The outermost surface on the side of the organic semiconductor layer 40 in the gate insulating film 30, that is, the base surface of the organic semiconductor layer 40 is an organic metal film 31a. Here, the sign is changed between the organic metal film 31 a on the outermost surface and the other organic metal film 31.

  The organic metal films 31a and 31 are made of, for example, Alcone and Zincone, and the inorganic metal oxide film 32 is made of, for example, alumina (AlOx), zirconium oxide (ZrO), hafnium oxide (HfO), and the like. Has been.

  However, in the present embodiment, as shown in FIG. 2, only the surface layer portion in the film thickness direction of the outermost organometallic film 31a is the inorganic metal oxide layer 31b formed by modification.

  That is, regarding the outermost organometallic film 31a, the surface layer portion of the film is an inorganic metal oxide layer 31b made of an inorganic metal oxide formed by modifying the organometal. The inner layer portion of the oxide layer 31b is an organic metal layer that remains an organic metal.

Here, the reforming method is not limited, and examples thereof include UV (ultraviolet) irradiation. For example, when the organic metal constituting the outermost organic metal film 31a is alcon, the modification by UV irradiation breaks the al-CO bond, resulting in a chemical reaction represented by the following chemical formula 1. Wake up.
(Chemical formula 1)
_{-O- -Al-O-CH 2 -CH} 2 ( Arukon) → -Al-O- (alumina)
Thereby, only the surface layer portion of the alcone is modified to the inorganic metal oxide layer 31b made of alumina.

  Here, if the outermost organic metal film 31a is too thick, only the surface layer portion of the entire outermost organic metal film 31a is modified to form the inorganic metal oxide layer 31b, so that the inner organic metal portion remains thick. Therefore, the characteristics of the organic metal film as a whole tend to be strong. As described above, when the organic metal film is used as the base of the organic semiconductor layer 40, the crystallinity of the organic semiconductor layer 40 is disturbed and the mobility is likely to decrease.

  Therefore, the thickness of the outermost organometallic film 31a is desirably less than 5 nm. Here, the inorganic metal oxide layer 31b on the surface layer side of the outermost organic metal film 31a is formed by modifying the organic metal by UV irradiation or the like, and has a thickness of 1 nm or less at most. It is. The remaining inner layer side is an organometallic layer.

  Further, the gate insulating film 30 of the present embodiment is configured by laminating an organic metal film and an inorganic metal oxide film, and the outermost surface is an organic metal film 31a having the inorganic metal oxide layer 31b. For example, it may be a two-layer structure in which one inorganic metal oxide film 32 and one organic metal film 31a are sequentially stacked from the substrate 10 side.

  However, preferably, as shown in FIG. 2, the gate insulating film 30 is formed by alternately laminating organic metal films 31a and 31 and inorganic metal oxide films 32 a plurality of times. Specifically, the inorganic metal oxide film 32, the organic metal film 31, the inorganic metal oxide film 32, the organic metal film 31,..., The inorganic metal oxide film 32, the outermost organic metal film 31a, and the like from the substrate 10 side. In addition, an organic metal film and an inorganic metal oxide film are repeatedly laminated. Here, the first film on the substrate 10 side may be the organic metal film 31 or the inorganic metal oxide film 32.

  In this case, the number of repetitions is not particularly limited. For example, the inorganic metal oxide film 32 has 1 to 10 layers, and the organic metal films 31a and 31 have 1 to 10 layers. Can be stacked alternately one by one. Further, the overall film thickness of the gate insulating film 30 is not limited, but can be, for example, less than about 100 nm.

  Next, the manufacturing method of the organic transistor of this embodiment is demonstrated with reference to FIG. 3, FIG.

[Step shown in FIG. 3A]
A substrate 10 based on an insulating flexible substrate such as non-alkali glass is prepared, and an electrode material such as Cr is formed on the surface of the substrate 10 by a sputtering method or the like to a thickness of, for example, 50 nm. Thereafter, the gate electrode 20 is formed by etching using a resist film pattern by photolithography.

[Step shown in FIG. 3B]
Next, a gate insulating film 30 covering the gate electrode 20 is formed on the substrate 10. The organic metal films 31a and 31 can be formed, for example, by a molecular deposition method (MLD: Molecular Layer Deposition). In the molecular deposition method, the organometallic films 31a and 31 are formed on the basis of sequential self-limiting surface reactions, and organic units are deposited by depositing “organic” units during the reaction in the molecular deposition method. Metal films 31a and 31 are formed.

  That is, the organic metal films 31a and 31 are described as a single or branched linear structure having a metal or metalloid unit and an organic unit. The outline of this repeating unit is represented by the following structural formula.

(Chemical formula 2)
[-M-Z-R-Z-]
In the above chemical formula, M is a metal or metalloid atom, preferably aluminum, titanium, zirconium, hafnium or the like. Each Z is preferably a heteroatom, particularly an oxygen atom. The R group is preferably a hydrocarbyl group or a substituted hydrocarbyl group, and examples thereof include alkylene having 2 or more carbon atoms.

In the molecular deposition method, the organic metal films 31a and 31 of the organic-inorganic hybrid polymer can be realized by using both the inorganic reactant and the organic reactant. For example, Al (CH ₃ ) and trimethylaluminum (hereinafter referred to as TMA) easily react with a chemical species containing oxygen, and TMA and ethylene glycol (hereinafter referred to as EG) (HO— (CH ₂ ) ₂ —OH). Can be used together in a sequential stepwise process to deposit organometallic films 31a, 31 of an organic-inorganic hybrid polymer known as Alcon.

Specifically, the substrate 1 on which the gate electrode 20 is formed is exposed to TMA, thereby forming a single layer in which TMA is chemically adsorbed. After adsorption, excess TMA in the gas phase is removed by purging with nitrogen (N ₂ ).

  Next, when the sample after chemical adsorption of the TMA monolayer is exposed to EG, it reacts with the TMA monolayer to form an alcon layer. Thereafter, by removing the reaction product (in this case, methane) and excess EG, one cycle of film formation is completed, and this is used as one layer of the organic metal films 31a, 31 to obtain the desired film thickness. Repeat until Such organic metal films 31a and 31 can be formed at a high temperature (eg, 130 ° C.).

On the other hand, the inorganic metal oxide film 32 can be formed by, for example, an atomic layer deposition (ALD) method. In the atomic layer deposition method, a plurality of gases as raw materials are alternately switched and guided onto the substrate 10, and a monoatomic layer (gas molecule layer) is formed on the substrate 10 by chemical adsorption. Inorganic layers are formed one by one by a chemical reaction. For example, when the inorganic metal oxide film 32 is made of alumina, (TMA) is used as the Al source, and water (H ₂ O) or the like is used as the oxygen (O) source.

Specifically, the substrate 10 on which the organic metal film 31 is formed is exposed to TMA, thereby forming a single layer in which TMA is chemically adsorbed. After adsorption, excess TMA in the gas phase is removed by purging with nitrogen (N ₂ ). Next, when the sample after chemical adsorption of the TMA monolayer is exposed to water vapor, it reacts with the TMA monolayer to form an Al ₂ O ₃ layer.

Thereafter, by removing the reaction product (in this case, methane) and excess H ₂ O, one cycle of film formation is completed, and this is used as one layer of the inorganic metal oxide film 32 to achieve the desired film thickness. Repeat until obtained.

  The inorganic metal oxide film 32 is formed in a precursor-specific temperature region called “ALD window” (for example, 130 ° C.) so that the growth of the film becomes linear and the thickness is reduced to angstroms. It becomes possible to control on a (0.1 nm) scale.

  By forming the organic metal films 31a and 31 and the inorganic metal oxide film 32 a predetermined number of times, the organic metal films 31a and 31 and the inorganic metal oxide film 32 are stacked, and the outermost surface is formed. A laminated film is formed as the organic metal film 31a. Thus, the film formation is substantially completed in the formation of the gate insulating film 30.

  This laminated film is etched into a desired shape by a photolithographic method or the like as necessary. This is the first step in the step of forming the gate insulating film 30. In the state up to this point, the outermost organometallic film 31a is the one before the modification, and the entire film is made of an organic metal.

  Next, although not shown in the drawing, a water cleaning process is performed in which the surface of the substrate 10 including the outermost organometallic film 31a is cleaned with water. This is performed in order to remove residues remaining by the above-described etching or the like.

  Specifically, the surface of the substrate 10 is washed with running water using pure water, or is washed by immersing the substrate 10 in a water tank. At this time, since the surface layer portion of the outermost metal organic film 31a in the gate insulating film 30 is an organic metal excellent in water resistance, occurrence of film loss is prevented as much as possible.

[Step shown in FIG. 3 (c)]
After this water cleaning step, the substrate 10 is dried, and then the second step in the step of forming the gate insulating film 30 is performed. In this second step, only the surface layer portion in the film thickness direction of the outermost organometallic film 31a is modified to form the inorganic metal oxide layer 31b.

  Specifically, the organic metal portion located on the surface layer of the outermost organometallic film 31a is modified to the inorganic metal oxide layer 31b by irradiating with ultraviolet rays (UV). For example, the reforming reaction from alcon to alumina is as described above.

  The modification method is not limited to UV irradiation, and is not particularly limited as long as it can provide other light irradiation or reaction energy for causing a modification reaction. .

  Thus, according to the second step shown in FIG. 3C, the gate insulating film 30 in which the surface layer portion of the outermost organometallic film 31a is modified to the inorganic metal oxide layer 31b, that is, as a finished product. A gate insulating film 30 is completed.

[Step shown in FIG. 4A]
Next, the organic semiconductor layer 40 is formed on the gate insulating film 30 by coating or the like. For example, the organic semiconductor layer 40 is formed by forming a thiophene-based organic semiconductor material (for example, C8-BTBT) to a thickness of 40 nm by a drop cast method. At this time, since the surface layer portion of the organic metal film 31a on the outermost surface of the gate insulating film 30 is composed of the inorganic metal oxide layer 31b, the organic semiconductor layer 40 can be formed with a good film quality with good crystallinity. It becomes possible.

[Step shown in FIG. 4B]
Next, the source electrode 50 and the drain electrode 60 are formed in contact with the organic semiconductor layer 40 on the gate insulating film 30 while overlapping with the gate electrode 20. Specifically, the source electrode 50 and the drain electrode 60 are formed by forming an Au layer with a thickness of 50 nm on the surface of the organic semiconductor layer 40 by, for example, a vacuum deposition method using a shadow mask. In this way, the organic transistor according to this embodiment can be manufactured.

  By the way, according to the present embodiment, the water cleaning process is performed on the gate insulating film 30 before the surface layer portion of the outermost organometallic film 31a is modified. Since the surface layer portion of the organic metal film 31a is made of an organic metal and has high water resistance, film loss due to water washing is prevented.

  Then, after the water washing step, the surface layer portion of the outermost organic metal film 31a is modified to form the inorganic metal oxide layer 31b, so that the inorganic metal oxide layer 31b eventually becomes the base of the organic semiconductor layer 40. The gate insulating film 30 is formed. Therefore, the organic semiconductor layer 40 is formed with good crystallinity, and high mobility is ensured.

  Thus, according to the present embodiment, it is possible to provide an organic transistor having a configuration suitable for achieving both water resistance and high mobility, and a manufacturing method for appropriately manufacturing such an organic transistor. it can.

  In addition, as shown in FIG. 2, when the gate insulating film 30 of the present embodiment is formed by alternately laminating the organic metal films 31a and 31 and the inorganic metal oxide film 32 a plurality of times, the outermost layer in the gate insulating film 30 is formed. The thickness of the organic metal film 31 other than the organic metal film 31a on the surface is desirably less than 1 nm.

  This has been found experimentally by the present inventors. By setting the thickness of the organic metal film 31 other than the outermost organic metal film 31a to less than 1 nm, the inorganic metal oxide film 32 and the organic metal film 31 are obtained. It is easy to suppress peeling at the laminated portion. Specifically, as shown in FIG. 5, the peeling occurs at the interface between the inorganic metal oxide film 32 and the organic metal film 31 during UV irradiation.

  For example, the inorganic metal oxide film 32 in the gate insulating film 30 was made of alumina having a film thickness of 2.2 nm to 7.7 nm, and the presence or absence of peeling was examined by changing the film thickness of the organic metal film 31 made of alcon.

  As a result, peeling did not occur when the thickness of the organometallic film 31 made of alcon was 0.95 nm, whereas peeling occurred when the film thickness was 1.6 nm or 2.3 nm. . From this, it can be said that the thickness of the organic metal film 31 other than the outermost organic metal film 31a is preferably less than 1 nm.

(Other embodiments)
In the above embodiment, the organic semiconductor layer 40 is formed on the gate insulating film 30 and then the source electrode 50 and the drain electrode 60 are formed thereon. However, the organic transistor may have a structure in which the organic semiconductor layer 40 is applied after the source electrode 50 and the drain electrode 60 are formed on the gate insulating film 30. That is, in the said embodiment, it is good also as a structure where the vertical relationship of the organic-semiconductor layer 40, the source electrode 50, and the drain electrode 60 was replaced.

  In addition, the water cleaning process is performed between the first process and the second process in the process of forming the gate insulating film 30. For example, if necessary, after the gate electrode 20 is formed, the gate insulating process is performed. Prior to the formation of the film 30, the same water cleaning may be performed on the surface of the substrate 10.

  Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope described in the claims. The above embodiments are not irrelevant to each other, and can be combined as appropriate unless the combination is clearly impossible, and the above embodiments are not limited to the illustrated examples. Absent. In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily indispensable except for the case where it is clearly indicated that the element is essential and the case where the element is clearly considered essential in principle. Yes. Further, in each of the above embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, it is clearly limited to a specific number when clearly indicated as essential and in principle. The number is not limited to the specific number except for the case. Further, in each of the above embodiments, when referring to the shape, positional relationship, etc. of the component, etc., the shape, unless otherwise specified and in principle limited to a specific shape, positional relationship, etc. It is not limited to the positional relationship or the like.

DESCRIPTION OF SYMBOLS 10 Substrate 20 Gate electrode 30 Gate insulating film 31 Organometallic film 31a in gate insulating film 31a Organic metal film on outermost surface in gate insulating film 31b Inorganic metal oxide layer in organic metal film on outermost surface 32 Inorganic metal oxide film in gate insulating film 40 Organic semiconductor layer 50 Source electrode 60 Drain electrode

Claims (5)

A substrate (10);
A gate electrode (20) formed on the substrate;
A gate insulating film (30) covering the gate electrode on the substrate;
A source electrode (50) and a drain electrode (60) which are spaced apart from each other via the gate insulating film on the gate electrode;
An organic semiconductor layer (40) formed on the surface of the gate insulating film so as to connect at least the source electrode and the drain electrode;
The gate insulating film is formed by laminating organic metal films (31a, 31) and an inorganic metal oxide film (32), and the outermost surface on the organic semiconductor layer side is the organic metal film. And
Only the surface layer portion in the film thickness direction of the organic metal film (31a) on the outermost surface is an inorganic metal oxide layer (31b) formed by modification.   2. The organic transistor according to claim 1, wherein the thickness of the outermost organometallic film is less than 5 nm.   3. The organic transistor according to claim 1, wherein the gate insulating film is formed by alternately laminating the organic metal film and the inorganic metal oxide film a plurality of times.   4. The organic transistor according to claim 3, wherein the thickness of the organic metal film (31) other than the organic metal film (31 a) on the outermost surface of the gate insulating film is less than 1 nm. Preparing a substrate (10);
Forming a gate electrode (20) on the substrate;
Forming a gate insulating film (30) covering the gate electrode on the substrate;
Forming an organic semiconductor layer (40) on the gate insulating film;
Forming a source electrode (50) and a drain electrode (60) in contact with the organic semiconductor layer on the gate insulating film while overlapping with the gate electrode, and a method of manufacturing an organic transistor,
In the step of forming the gate insulating film, an organic metal film (31a, 31) and an inorganic metal oxide film (32) are stacked, and the outermost surface on the organic semiconductor layer side is the organic metal film (31a). A first step of forming the laminated film, and after the first step, only the surface layer portion in the film thickness direction of the organic metal film on the outermost surface is modified to form an inorganic metal oxide layer (31b) And a second step to
Performing a water cleaning step of cleaning the surface of the substrate including the outermost organometallic film with water between the first step and the second step in the step of forming the gate insulating film; An organic transistor manufacturing method characterized by the above.

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