JP2007012877A - Thin film transistor and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an organic thin film transistor which has stably realized high mobility with smooth transfer of charges among a source electrode, a drain electrode, and a channel on the gate insulating layer. <P>SOLUTION: A gate electrode 11 is provided on a substrate 10. A gate insulating layer 12 is provided on the gate electrode 11. An organic electronic material layer 13 is provided on the gate insulating layer 12. A spacer 30 is provided to a gap region between the regions for providing the source electrode and drain electrode on the organic electronic material layer 13. The organic electronic material layer 13 in the region where the source electrode and/or drain electrode is provided is removed up to the predetermined depth. A source electrode 15 and a drain electrode 14 are provided to the region to provide the source electrode and drain electrode on the gate insulating layer 12 and/or organic electronic material layer 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thin film transistor using an organic electronic material.

  In recent years, the spread of flat displays for information equipment has been remarkable. Among these, a liquid crystal display obtains color using a color filter by controlling on / off of backlight light by an optical shutter function of liquid crystal. On the other hand, in an organic EL display (or organic LED display), each pixel emits light individually (that is, self-emission). For this reason, the organic EL display not only has the advantage of a wide viewing angle, but also has the advantage that it can be thinned because it does not require a backlight, and can be formed on a flexible substrate. Have the advantage of. For this reason, an organic EL display is expected as a next-generation display.

  The driving methods of these display panels can be roughly divided into two types. The first drive method is called a passive matrix type (or duty drive method, simple matrix method). In this case, a plurality of stripe electrodes are combined in rows and columns in a matrix, and pixels located at the intersections of the row electrodes and the column electrodes are caused to emit light by a drive signal applied to the row electrodes and the column electrodes. Signals for light emission control are usually scanned in time series for each row in the row direction, and are simultaneously applied to each column in the same row. In this method, each pixel is normally not provided with an active element, and light emission is controlled only during the duty period of each row in the row scanning period. The second driving method is an active matrix type in which each pixel has a switching element and can emit light over a scanning period of a row.

For example, assume that the entire panel of 100 rows × 150 columns emits light with a display luminance of 100 Cd / m ² . In this case, since each pixel basically emits light constantly in the active matrix type, light emission may be performed at 100 Cd / m ² when the area ratio of the pixel and various losses are not considered. However, when trying to obtain the same display brightness with the passive matrix type, the duty ratio for driving each pixel becomes 1/100, and only the duty period (selection period) becomes the light emission time. Needs to be 100 times 10,000 Cd / m ² .

  Here, in order to increase the light emission luminance, the current passed through the light emitting element may be increased. However, it is known that, for example, in an organic EL light emitting element, the current is increased and the luminous efficiency is lowered. Due to this reduction in efficiency, when the active matrix type driving method and the passive matrix type driving method are compared with the same display luminance, the passive matrix type consumes a relatively large amount of power. Further, when the current flowing through the organic EL element is increased, there is a disadvantage that the material is likely to be deteriorated due to heat generation and the life of the display device is shortened. On the other hand, if the maximum current is limited from the viewpoints of efficiency and lifetime, it is necessary to lengthen the light emission period in order to obtain the same display luminance. However, since the duty ratio that determines the light emission time in the passive matrix driving method is the reciprocal of the number of rows of the panel, the extension of the light emission period leads to the limitation of the display capacity (number of drive lines). From these points, it is necessary to use an active matrix type driving method in order to realize a large-area, high-definition panel. FIG. 5 is a conceptual diagram illustrating an equivalent circuit for controlling a light emitting element using a thin film transistor. As a basic circuit for normal active matrix driving, a method using a thin film transistor as a switching element is known as shown in FIG.

  In an active matrix driving method suitable for a large area and high definition, a thin film transistor (TFT) using polysilicon is most widely used as a pixel switching element. However, for example, the process temperature for forming a TFT using polysilicon is a high temperature of at least 250 ° C., which makes it difficult to use a flexible plastic substrate.

  In order to cope with various problems of such a conventional display panel, it has been proposed to use an organic thin film transistor element. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2001-250680) discloses a technique for connecting an organic thin film rectifying element in series with an organic thin film light emitting unit. Patent Document 2 (WO01 / 15233) discloses a technique for controlling driving of a pixel by an organic thin film transistor. According to the disclosure of Patent Document 2, since the driving element is made of an organic material, a manufacturing process at a low temperature is possible, and thus a flexible plastic substrate can be used. In addition, since inexpensive materials and processes can be selected, the cost can be reduced.

JP 2001-250680 A WO01 / 15233 JP 2004-266267 A C.D.Sheraw, et.al., Applied Physics Letters Vol.80 (2002) p.1088

  However, such an organic thin film transistor has the following problems.

  FIG. 6 shows a cross-sectional view of a conventional bottom contact type organic thin film transistor. FIG. 7 shows a cross-sectional view of a conventional top contact type organic thin film transistor. As shown in FIGS. 6 and 7, the typical structure of the organic thin film transistor is roughly classified into one called a bottom contact and one called a top contact.

  As shown in FIG. 6, in the bottom contact, a gate electrode 111 is provided on a substrate 110, and a source electrode 115 and a drain electrode 114 are formed directly or on an adhesive layer on a gate insulating layer 112 provided thereon. After that, the organic electronic material layer 113 is formed. On the other hand, as shown in FIG. 7, in the top contact, after the gate electrode 211 is provided on the substrate 210 and the organic electronic material layer 213 is formed on the gate insulating layer 212 provided thereon, A source electrode 215 and a drain electrode 214 are formed thereon. In either case, the gate voltage applied to the gate electrode induces a charge in the portion of the organic electronic material layer in contact with the gate insulating layer, and the charge moves due to the voltage applied between the source electrode and the drain electrode. Current flows. That is, a current flows between the source electrode and the drain electrode through the organic electronic material layer in contact with the gate insulating layer, and this current can be controlled by the potential of the gate electrode. The current path between the source electrode and the drain electrode is called channels 116 and 216. The channel is usually formed in a very thin portion of several molecular layers of the organic electronic material layer in contact with the gate insulating layer.

    Examples of the organic electronic material used for the organic thin film transistor include pentacene, thiophene, hexythiophene-based polymer, fluorenethiophene-based polymer, copper phthalocyanine, and fullerene. Of these, particularly low molecular weight materials such as pentacene, thiophene, copper phthalocyanine, and fullerene, when formed by vacuum vapor deposition, are polycrystalline thin films. In addition, it has been found that the crystal orientation differs depending on the film formation conditions and the type of substrate, which greatly affects the characteristics of the transistor.

  For example, in the case of pentacene, which is most widely used, the metal oxide used for the gate insulating layer is oriented so that the longitudinal direction of the molecule stands with respect to the substrate, whereas the metal used for the source and drain electrodes It is known that the longitudinal direction of molecules is oriented parallel to the substrate on the film. FIG. 8 is a conceptual diagram schematically showing the crystal orientation of the organic electronic material in the bottom contact type organic thin film transistor. The electrical resistance of pentacene is higher in the direction perpendicular to the molecule than in the longitudinal direction. For this reason, in the structure of FIGS. 6 and 7 in which current flows parallel to the gate insulating layer, the crystal orientation on the insulating film is suitable. However, as shown in FIG. 8, in the case of the bottom contact structure, the crystallinity of pentacene or the like at the boundary between the gate insulating layer and the source and drain electrodes is disturbed, and the electrical resistance increases there. The problem occurs.

  The top contact is a structure for avoiding the problems of the bottom contact as described above. That is, in this structure, since the organic electronic material layer such as pentacene is formed only on the gate insulating layer, there is no discontinuity in crystal orientation. For this reason, generally, the charge mobility is higher than that of the bottom contact. However, since there is an organic electronic material layer between the current path (channel) formed on the gate insulating layer and the source electrode and the drain electrode, there is another problem that this causes an increase in electric resistance. This is partly because, as described above, in a thin film such as pentacene, the electrical resistance in the molecular longitudinal direction is higher than that in the vertical direction of the molecule. In order to alleviate this problem, it is desirable to reduce the thickness of the organic electronic material layer. FIG. 9 is a conceptual diagram schematically showing a crystal growth state of an organic electronic material in a top contact type organic thin film transistor when the organic electronic material is thin. As shown in FIG. 9, generally, an organic material thin film grows in an island shape on a substrate. Therefore, when the film thickness is small, the organic electronic material cannot cover the entire surface of the substrate, and a spatial defect 222 is likely to occur. . If there is such a defect, the electrical resistance to the current 224 in the channel is increased, so that the resistance as a transistor element is lowered. For this reason, the organic electronic material layer needs to have a certain thickness or more in the top contact, and has not yet been solved.

  Another problem with the top contact structure is that it is difficult to control the channel length (distance between the source electrode and the drain electrode) because the organic electronic material thin film is generally chemically and mechanically fragile. . That is, conventionally, in order to avoid damage to the organic electronic material thin film, for example, in the case of formation by vacuum vapor deposition, patterning by shadow mask vapor deposition has been common. In this case, variation in channel length due to mask blur is inevitable, and a channel length of about 30 μm or less cannot be formed due to mask thickness or the like.

  As described above, in any structure, a large electric resistance exists between the source electrode, the drain electrode, and the channel, which adversely affects static electric characteristics and responsiveness to high-frequency signals. When the electric resistance of the current path is large, the voltage applied between the source electrode and the drain electrode is consumed in that portion, and the mobility of the element is lowered, which is a serious problem.

  Therefore, in view of the above points, an object of the present invention is to provide means for smoothly realizing high mobility in an organic thin film transistor by smoothing charge transfer between a source electrode, a drain electrode, and a channel on a gate insulating layer. To do.

According to one aspect of the present invention, a method of manufacturing a thin film transistor, comprising:
Providing a substrate;
Providing a gate electrode on the substrate;
Providing a gate insulating layer on the gate electrode;
Providing an organic electronic material layer on the gate insulating layer;
Providing a spacer portion in a gap region between the region where the source electrode is provided and the region where the drain electrode is provided on the organic electronic material layer;
Removing the organic electronic material layer in a region where the source electrode is provided and / or a region where the drain electrode is provided to a predetermined depth;
Providing a source electrode in a region where the source electrode is provided on the gate insulating layer and / or the organic electronic material layer;
Providing a drain electrode in a region where the drain electrode is provided on the gate insulating layer and / or the organic electronic material layer.

According to another aspect of the present invention, a method of manufacturing a thin film transistor, comprising:
Providing the substrate;
Providing a gate electrode on the substrate;
Providing a gate insulating layer on the gate electrode;
Providing an organic electronic material layer on the gate insulating layer;
Providing a spacer portion in a gap region between the region where the source electrode is provided and the region where the drain electrode is provided on the organic electronic material layer;
Providing a source electrode in a region where the source electrode is provided on the gate insulating layer and / or the organic electronic material layer so that an upper surface of the source electrode is lower than an upper surface of the spacer portion;
Providing a drain electrode in a region where the drain electrode is provided on the gate insulating layer and / or the organic electronic material layer such that an upper surface of the drain electrode is lower than an upper surface of the spacer portion; A method of including is provided.

According to another aspect of the present invention, a thin film transistor comprising:
A substrate,
A gate electrode provided on the substrate;
A gate insulating layer provided on the gate electrode;
A source electrode;
A drain electrode;
An organic electronic material layer provided at least in a gap region between the source electrode and the drain electrode on the gate insulating layer, wherein the organic electronic material layer includes the source electrode and / or the drain An organic electronic material having a smaller thickness of the organic electronic material layer in the region under the source electrode and / or the drain electrode than in the gap region, when further provided in the region under the electrode Layers,
There is provided a thin film transistor having a spacer portion provided in the gap region on the organic electronic material layer.

According to another aspect of the present invention, a thin film transistor comprising:
A substrate,
A gate electrode provided on the substrate;
A gate insulating layer provided on the gate electrode;
A source electrode;
A drain electrode;
A gap region between the source electrode and the drain electrode on the gate insulating layer and an organic electronic material layer provided in a region under the source electrode and / or the drain electrode, the gap region An organic electronic material layer having a small thickness of the organic electronic material layer in a region under the source electrode and / or the drain electrode,
A thin film transistor is provided.

According to another aspect of the present invention, a thin film transistor comprising:
A substrate,
A gate electrode provided on the substrate;
A gate insulating layer provided on the gate electrode;
A source electrode provided on the gate insulating layer;
A drain electrode provided on the gate insulating layer;
An organic electronic material layer provided in a gap region between the source electrode and the drain electrode on the gate insulating layer, wherein the organic electronic material layer includes a crystalline material, and the crystalline material is An organic electronic material layer oriented in substantially the same direction;
A thin film transistor is provided.

According to another aspect of the present invention, a thin film transistor comprising:
A substrate,
A gate electrode provided on the substrate;
A gate insulating layer provided on the gate electrode;
An organic electronic material layer provided on the gate insulating layer;
A source electrode provided on the organic electronic material layer;
A drain electrode provided on the organic electronic material layer;
A spacer portion provided in a gap region between the source electrode and the drain electrode on the organic electronic material layer, wherein an upper surface of the spacer portion is an upper surface of the source electrode and the drain electrode. A spacer part higher than the upper surface of
A thin film transistor is provided.

  According to the present invention, in an organic thin film transistor, it is possible to provide means for smooth charge transfer between a source electrode, a drain electrode, and a channel on a gate insulating layer, thereby realizing high mobility and frequency characteristics.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

1 to 3 are conceptual diagrams showing a method of manufacturing a thin film transistor according to the first and second embodiments of the present invention. According to the first and second embodiments of the present invention, a method of manufacturing a thin film transistor,
Providing a substrate 10 (see FIG. 1A);
Providing a gate electrode 11 on the substrate (see FIG. 1A);
Providing a gate insulating layer 12 on the gate electrode (see FIG. 1A);
Providing an organic electronic material layer 13 on the gate insulating layer (see FIG. 1A);
Providing a spacer portion 30 in a gap region between the region where the source electrode is provided and the region where the drain electrode is provided on the organic electronic material layer (see FIGS. 1B and 1C);
Removing the organic electronic material layer in a region where the source electrode is provided and / or a region where the drain electrode is provided to a predetermined depth (see FIGS. 2D-1 and 3D-2);
Providing a source electrode 15 in a region where the source electrode is provided on the gate insulating layer and / or the organic electronic material layer (see FIGS. 2 (e-1) and 3 (e-2));
Providing a drain electrode 14 in a region where a drain electrode is provided on the gate insulating layer and / or the organic electronic material layer (see FIGS. 2 (e-1) and 3 (e-2)). Is done.

  The manufacturing method according to the present invention includes a step of providing a substrate 10 (see FIG. 1A). Examples of materials that can be used for the substrate include various glass substrates and polymer films such as polyimide, PEEK, and PET.

  The manufacturing method according to the present invention further includes a step of providing the gate electrode 11 on the substrate (see FIG. 1A). The gate electrode can be provided by vacuum deposition, spin coating, sputtering, or the like. At this time, the gate electrode can be patterned by a shadow mask or a photo process as necessary. Examples of materials that can be used for the gate electrode include various metal materials and organic conductive materials. The material used for the gate electrode is preferably determined in consideration of the adhesion to the substrate and the ease of forming a gate insulating layer described later. For example, tantalum is preferable as a material used for the gate electrode. This is because an anodized film obtained by anodizing tantalum can be used as a gate insulating layer.

  The manufacturing method according to the present invention further includes a step of providing a gate insulating layer 12 on the gate electrode (see FIG. 1A). The gate insulating layer can be provided by vacuum deposition, spin coating, or the like. At this time, the gate insulating layer can be patterned by a shadow mask or a photo process as necessary. Examples of materials that can be used for the gate insulating layer include various metal oxides such as silicon, aluminum, tantalum, titanium, strontium, and barium oxides, anodic oxide films of these metals, and mixed oxides of these oxides. Can be mentioned. In addition, polymer materials such as polymer materials such as polystyrene, polyvinyl alcohol, polyvinyl phenol, and acrylic can also be used. In particular, many metal oxides have a dielectric constant higher than that of a polymer material, and the transistor can be driven at a relatively low voltage. On the other hand, the polymer material has a characteristic that the high-speed response is good because the dielectric constant is relatively low.

  The manufacturing method according to the present invention further includes a step of providing an organic electronic material layer 13 on the gate insulating layer (see FIG. 1A). The organic electronic material layer can be provided by vacuum deposition, spin coating, or the like. As described in detail below, the present invention is suitable when the organic electronic material layer contains a crystalline material.

（式中、Ｒは、水素、置換基を有しても良い炭素数１〜６のアルキル基、置換基を有しても良いアリール基、置換基を有しても良い炭素数１〜６のアルコキシ基、

またはアントラセン骨格と芳香環もしくは複素環を形成する残基を表し、ｎは１〜１０の整数を表す。） In particular, the crystalline material is preferably an acene compound represented by the following structural formula (I). This is because these acene-based compound thin films have high crystallinity and high adhesion to the substrate, and therefore are more chemically and mechanically stable than other organic electronic material layers. It is.

(In the formula, R is hydrogen, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an aryl group which may have a substituent, or an optionally substituted carbon group having 1 to 6 carbon atoms. An alkoxy group of

Alternatively, it represents a residue that forms an aromatic ring or a heterocyclic ring with an anthracene skeleton, and n represents an integer of 1 to 10. )

等が挙げられるが、これらに限定されるものではない。また、Ｒは、アントラセン骨格と芳香環もしくは複素環を形成する残基であってもよく、例えば、アントラセン骨格と縮合して芳香環もしくは複素環を形成する残基であってもよい。このようなＲの例として、下式Ｉ−１３〜Ｉ−１５，Ｉ−１８〜Ｉ−２６に記載のものが挙げられる。 As R in the acene-based material represented by the above formula (I), hydrogen, methyl, phenyl, p-methoxyphenyl, methoxy,

However, it is not limited to these. R may be a residue that forms an aromatic ring or a heterocyclic ring with an anthracene skeleton. For example, R may be a residue that forms an aromatic ring or a heterocyclic ring by condensing with an anthracene skeleton. Examples of such R include those described in the following formulas I-13 to I-15 and I-18 to I-26.

Specific examples of the acene-based material of the organic semiconductor layer material include the following structural formulas (I-1) to (I-26).

  Examples of materials that can be used for the organic electronic material layer include pentacene, thiophene, hexthiophene polymer, fluorene thiophene polymer, copper phthalocyanine, and fullerene, in addition to the acene compound. The materials that can be used for the organic electronic material layer are not limited to these, and many organic electronic materials are applicable.

  In the present invention, as described later, the organic electronic material layer in the region where the source electrode is provided and / or the region where the drain electrode is provided can be removed, but the region which is not removed (the region where the source electrode is provided and the drain electrode) The thickness of the organic electronic material layer in the gap region between the region and the region where the first electrode is provided is preferably 1 to 100 nm, and more preferably 5 to 50 nm. For example, in the case of pentacene, which is a typical acene-based material, its molecular length is about 1.5 nm, and it is preferably oriented in a state of standing in a substantially vertical direction on the substrate. Then, the thin layer is formed by laminating the layers having a thickness of about 1.5 nm, and the current flows perpendicularly to the molecular longitudinal direction (parallel to the substrate). In particular, in the element of the present invention, the current flows in a concentrated manner on the gate insulating film side, but the region is in the range of several molecular layers. The thickness of the molecular layer varies depending on the structure of the organic electronic material, but is about 1 to 2 nm, and the lower limit of the organic electronic material layer is equivalent to that value. There is no particular upper limit on the thickness of the organic electronic material layer in the structure of the present invention, but since the region contributing to electrical conduction is a few molecular layers as described above, it is useful to make it thicker than the above range. There is no effect, and it is reasonable from the viewpoint of process cost to stop at the above value.

  As described above, in the present invention, since the organic electronic material layer is provided before the source electrode and the drain electrode are provided, the crystal is oriented even in the vicinity of the source electrode and the drain electrode as in the above-described bottom contact type transistor. There is no disturbance. That is, according to the present invention, it is possible to provide a thin film transistor in which the organic electronic material layer includes a crystalline material and the crystalline material is oriented in substantially the same direction.

  Note that the orientation state of the crystalline material in the organic electronic material layer, that is, whether or not the crystalline material is oriented in substantially the same direction in the organic electronic material layer can be measured as follows. There are several methods for analyzing the orientation of a thin film, but the X-ray diffraction method generally performed is the simplest. For example, by comparing the diffraction angle intensity between the normal θ-2θ method (out-of-plane method) and the low-angle incidence method (in-plane method) with a small incident angle of X-rays on the thin film, the orientation can be outlined. You can get to know. It is also possible by analyzing the second harmonic component of the reflected light of laser irradiation.

The manufacturing method according to the present invention further includes a step of providing a spacer portion 30 in a gap region between the region where the source electrode is provided and the region where the drain electrode is provided on the organic electronic material layer (FIG. 1B and (See (c)). For example, the step
Applying a photoresist material on the organic electronic material layer (see FIG. 1B);
Of the applied photoresist material, the region where the source electrode is provided and the region where the drain electrode is provided are not irradiated with electromagnetic waves, but the gap regions are irradiated with electromagnetic waves, and the photoresist materials are cured in the gap regions. And the stage
And removing the uncured photoresist material (see FIG. 1 (c)).

  The step of applying the photoresist material can be performed by a method such as spin coating. The step of irradiating the predetermined region of the applied photoresist material with the electromagnetic wave can be performed by photolithography. At this time, the gap region is irradiated with electromagnetic waves, but the region where the source electrode is provided and the region where the drain electrode is provided are not irradiated with electromagnetic waves. By this step, the photocrosslinking reaction can be caused and the spacer material can be cured in the gap region. On the other hand, the photoresist material is not cured in the region where the source electrode is provided and the region where the drain electrode is provided where no electromagnetic wave is irradiated. Furthermore, the step of removing the uncured photoresist material can be performed by washing with a developer such as water or an organic solvent. The developing solution at this time can be appropriately selected according to the photoresist material used. At this time, a layer of a cured photoresist material may be provided in a region other than the region where the source electrode is provided, the region where the drain electrode is provided, and the gap region as long as the function of the transistor is not hindered.

  Note that the photoresist material widely refers to a material that can be cured by irradiation with an electromagnetic wave having a predetermined wavelength. In particular, the photoresist material is preferably a material obtained by adding a photosensitizing material such as ammonium dichromate to polyvinyl alcohol or the like. That is, the photoresist material preferably contains polyvinyl alcohol. In addition, it is preferable that number average molecular weights (GPC measurement, polystyrene conversion), such as polyvinyl alcohol, are 30,000-190,000. An example of the photosensitizing material is ammonium bichromate. This is because polyvinyl alcohol is water-soluble, and when it is used as a photoresist, it is possible to use water as a developer, so that the chemical effect on the organic electronic material layer can be reduced. is there. On the other hand, when an organic electronic material such as pentacene is exposed to an organic solvent other than water, the crystalline state of the organic electronic material changes depending on the combination of the organic electronic material and the organic solvent, processing conditions, etc. The characteristics may deteriorate.

  It should be noted that the addition of ammonium bichromate or the like to polyvinyl alcohol or the like has been conventionally performed to impart photosensitivity, and is a known technique. Further, it is disclosed in, for example, Non-Patent Document 1 (Sheraw et al., 2002) that a thin film of pentacene, which is an organic electronic material, can be photolithographed using such a material.

  Thus, the thin film transistor according to the first and second embodiments of the present invention is provided in the gap region between the region where the source electrode is provided and the region where the drain electrode is provided on the organic electronic material layer. Has a spacer part. Further, as described above, it is preferable that the spacer portion includes a cured photoresist material.

  Here, in the step of providing the spacer portion, (A) in the step of providing the source electrode, (i) in the step of removing the organic electronic material layer, the organic electronic material layer is partially removed in the thickness direction. If (first embodiment) or not removed, the distance in the thickness direction between the upper surface of the spacer portion and the upper surface in the region where the source electrode of the organic electronic material layer is provided, or (Ii) When the organic electronic material layer is completely removed in the thickness direction in the step of removing the organic electronic material layer (second embodiment), the upper surface of the spacer portion and the upper surface of the gate insulating layer It is preferable to provide the spacer portion so that the distance in the thickness direction between the first electrode and the second electrode is larger than the thickness of the source electrode. Similarly, in the step of providing the spacer portion, in the step of (B) providing the drain electrode, in the step of (i) removing the organic electronic material layer, the organic electronic material layer is partially removed in the thickness direction. If it is (first embodiment) or not removed, the distance in the thickness direction between the upper surface of the spacer portion and the upper surface in the region where the drain electrode of the organic electronic material layer is provided, or (Ii) When the organic electronic material layer is completely removed in the thickness direction in the step of removing the organic electronic material layer (second embodiment), the upper surface of the spacer portion and the upper surface of the gate insulating layer It is preferable to provide the spacer portion so that the distance in the thickness direction between the first electrode and the second electrode is larger than the thickness of the drain electrode. Specifically, the thickness of the spacer portion is preferably 1 μm or more when the thin film transistor is completed. In addition, the thickness of the spacer portion when the thin film transistor is completed is preferably 10 μm or less, and more preferably 5 μm or less.

  This is because the spacer portion is given a sufficiently large thickness compared to the thickness of the source electrode and the drain electrode, so that when the source electrode and the drain electrode are formed after the spacer portion is formed, the electric This is because the electrical insulation can be easily secured. In general, since the source electrode and the drain electrode are formed with a thickness of 60 to 100 nm, it is preferable that the thickness of the spacer portion is in the above range sufficiently thicker than that.

  For example, when the electrode material is attached by vacuum vapor deposition, the straightness of the material flying on the substrate during vapor deposition is high. For this reason, when the material comes perpendicular to the substrate, the electrode material hardly adheres to the side surface of the spacer portion. In addition, when the material flies at an angle, the electrode material does not adhere to at least the side surface of the spacer portion, so that the electrical insulation between the source electrode and the drain electrode is kept good. However, even in such a case, in order to further reduce the possibility of a short circuit due to scattering of the material flying during deposition, the thickness of the spacer portion is compared with the thickness of the source electrode and the drain electrode. It is preferable that it is sufficiently large. As a result of the study, the inventors have found that the possibility of short-circuiting can be almost ignored when the thickness of the spacer portion is in the above range.

  In addition to this, the spacer portion needs to remain after the etching of the organic electronic material layer described later. Usually, the thickness of the organic electronic material layer is about 50 nm, and even if the spacer portion is etched to the same extent as the thickness of the organic electronic material layer, it is sufficient if the thickness of the spacer portion is in the above range. Thickness can be maintained.

  In addition, the present invention is suitable when the length between the region where the source electrode is provided and the region where the drain electrode is provided corresponding to the channel length is 30 μm or less, and more preferably when the length is 3 to 5 μm. It is. The present invention is suitable when the width between the region where the source electrode is provided and the region where the drain electrode is provided is 20 μm or more, and more preferably when the width is 60 μm or more.

  In addition, it is preferable that the manufacturing method concerning this invention further includes the step which provides a protective layer on the organic electronic material layer before the step which provides a spacer part in the said gap | interval area | region. In other words, the thin film transistor according to the present invention preferably further includes a protective layer provided between the organic electronic material layer and the spacer portion. The protective layer can be provided on the organic electronic material layer without substantially degrading the organic electronic material layer, is resistant to a developer for the photoresist material used, and is formed in a predetermined region by etching or the like. Any material that can be removed only can be used. Specifically, parylene can be given as an example of a material that can be used for the protective layer.

  The step of providing a protective layer such as a parylene film can be performed by CVD. For this reason, when providing a parylene film, it is not necessary to use a solvent. Even if a photoresist material is applied on the parylene film after the parylene film is provided, and exposure and development are performed, the organic electronic material layer protected by the parylene is not deteriorated by the developer. As will be described later, the required spacer portion can be formed by further etching the region where the photoresist material has been removed by development with oxygen plasma or the like.

  It is preferable that the manufacturing method according to the present invention further includes a step of removing the organic electronic material layer in a region where the source electrode is provided and / or a region where the drain electrode is provided to a predetermined depth (FIG. 2 (d-1) and (Refer FIG.3 (d-2)). The removal to a predetermined depth means that only part of the organic electronic material layer is removed in the thickness direction (see the first embodiment, FIG. 2 (d-1)) and the gate insulating layer is reached ( (Completely) (see the second embodiment, FIG. 3 (d-2)). The step of removing the organic electronic material layer can be performed by etching. More specifically, the step of removing the organic electronic material layer can be easily performed by dry etching using oxygen plasma or ultraviolet irradiation.

  This is because by removing the spacer portion (photoresist material), the spacer portion residue is further removed from the region where the organic electronic material layer is exposed. That is, by removing the organic electronic material layer and shortening (or eliminating) the distance between the current path (channel) formed on the gate insulating layer and the source or drain electrode, the current path (channel) This is because the electric resistance in the organic electronic material layer between the source electrode and the drain electrode can be reduced. According to the manufacturing method according to the present embodiment, the organic electronic material layer is once formed as a film having a uniform thickness, and then the thickness of the film is reduced by etching or the like. Therefore, there is no problem such as island growth when the thickness of the organic electronic material layer is reduced in the above-described top contact transistor.

  In particular, for example, as described above, when the spacer portion is an insulator such as a photoresist material and the organic electronic material layer is a polycrystalline film, the crystal grain boundary (that is, the organic electronic material layer and An insulating photoresist material enters between the source electrode or the drain electrode and between the crystal grains of the organic electronic material. For this reason, the electrical resistance in the thickness direction of the organic electronic material layer may be larger than that of the above-described top contact transistor (the source electrode and the drain electrode are directly formed on the organic electronic material layer). The removal of the organic electronic material layer suppresses this influence to the minimum, and has a great effect on reducing the electric resistance by reducing the thickness of the organic electronic material layer described above.

  As described above, the thin film transistor according to the present invention includes the organic electronic material layer provided on the gate insulating layer at least in the gap region between the region where the source electrode is provided and the region where the drain electrode is provided. That is, the organic electronic material layer is formed on the gate insulating layer in the region where the source electrode is provided and / or the region where the drain electrode is provided, in addition to the gap region between the region where the source electrode is provided and the region where the drain electrode is provided. It can also be provided. In particular, when the organic electronic material layer is further provided on the gate insulating layer in the region where the source electrode is provided and / or the region where the drain electrode is provided, the region where the source electrode is provided and Alternatively, the thickness of the organic electronic material layer is preferably small in the region where the drain electrode is provided.

  The manufacturing method according to the present invention includes a step of providing a source electrode in a region where a source electrode is provided on the gate insulating layer and / or the organic electronic material layer, and a drain electrode on the gate insulating layer and / or the organic electronic material layer. And a step of providing a drain electrode in a region for providing (see FIGS. 2E-1 and 3E-2). That is, in the region where the source electrode is provided and / or the region where the drain electrode is provided, when the organic electronic material layer is only partially removed or not removed in the thickness direction, the source electrode and the drain electrode are ( It is provided on the organic electronic material layer (on the gate insulating layer) (see FIG. 2E-1). When the organic electronic material layer is completely removed in the thickness direction (up to the gate insulating layer) in the region where the source electrode is provided and the region where the drain electrode is provided, the source electrode and the drain electrode are Provided above (see FIG. 3 (e-2)). The step of providing the electrode can be performed by vacuum deposition, ink jet, or the like. At this time, a layer of a material used for the electrode may be provided in the region 31 other than the region where the source electrode is provided and the region where the drain electrode is provided as long as the function of the transistor is not hindered.

  In the present invention, in the step of providing the source electrode, the source electrode is provided such that the upper surface of the source electrode is lower than the upper surface of the spacer portion, and in the step of providing the drain electrode, the upper surface of the drain electrode is provided. It is preferable that the drain electrode is provided so that is lower than the upper surface of the spacer portion. As described above, this can more easily maintain good electrical insulation between the source electrode and the drain electrode, and can further reduce the possibility of a short circuit between the source electrode and the drain electrode. it can. Note that the upper surfaces of the source electrode, the drain electrode, and the spacer portion are those surfaces on the side opposite to the substrate when the thin film transistor is completed.

  Examples of materials that can be used for the source electrode and the drain electrode include various metal materials and organic conductive materials. For example, when an organic electronic material is used for the source electrode and the drain electrode and the charge moving through the organic electronic material is a hole, the hole injection at the source electrode is promoted and the electron injection at the drain electrode is suppressed. Therefore, a material such as gold having a large work function is generally used as the electrode material.

  The manufacturing method according to the present invention may further include a step of providing an auxiliary layer between the source electrode and the organic electronic material layer and / or between the drain electrode and the organic electronic material layer. That is, in the first and second embodiments shown in FIGS. 1 to 3, the source electrode and the drain electrode are shown as a single layer. For example, an auxiliary layer that facilitates charge injection is used as an organic electron. It is also possible to provide between the material layers easily. As an example of a material that can be used for the auxiliary layer, an organic electronic material doped with an electron-accepting material or an electron-donating material can be given. For example, in the case of the organic electronic material pentacene, F4TCNQ can be doped as a p-type impurity.

  The manufacturing method according to the present invention may further include a step of removing the spacer portion in the gap region. The step of removing the spacer portion can be performed by any method as long as the portion other than the spacer portion necessary for the transistor is not damaged. Specifically, the step of removing the spacer portion can be performed by immersing in a stripping solution (caustic soda or the like) that does not affect the substrate or thin film, and applying vibration with ultrasonic waves as necessary.

Thus, according to the first embodiment of the present invention, a thin film transistor,
A substrate 10;
A gate electrode 11 provided on the substrate;
A gate insulating layer 12 provided on the gate electrode;
A source electrode 15;
A drain electrode 14;
A gap region between the source electrode and the drain electrode on the gate insulating layer and an organic electronic material layer provided in a region under the source electrode and / or the drain electrode, the gap region Compared to the source electrode and / or the drain electrode, the organic electronic material layer has a small thickness, the organic electronic material layer includes a crystalline material, and the crystalline material is substantially the same. An organic electronic material layer 13 oriented in a direction;
There is provided a thin film transistor having a spacer portion 30 provided in the gap region on the organic electronic material layer.

The second embodiment of the present invention is a thin film transistor,
A substrate 10;
A gate electrode 11 provided on the substrate;
A gate insulating layer 12 provided on the gate electrode;
A source electrode 15 provided on the gate insulating layer;
A drain electrode 14 provided on the gate insulating layer;
An organic electronic material layer provided in a gap region between the source electrode and the drain electrode on the gate insulating layer, wherein the organic electronic material layer includes a crystalline material, and the crystalline material is substantially The organic electronic material layer 13 oriented in the same direction,
There is provided a thin film transistor having a spacer portion 30 provided in the gap region on the organic electronic material layer.

  These thin film transistors are compared with the bottom contact type transistor shown in FIG. 6 and the top contact type transistor shown in FIG. In FIG. 4, the conceptual diagram which showed typically the orientation of the crystal | crystallization of the organic electronic material in this invention is shown. In the transistor according to the present invention, since the organic electronic material layer is basically formed on the gate insulating layer, the crystal orientation is not disturbed even in the vicinity of the source electrode or the drain electrode. That is, since there is no disorder of the crystallinity of the organic electronic material in the vicinity of the source electrode and the drain electrode, which is a problem in the bottom contact, the contact resistance between the electrode and the organic electronic material is reduced. In particular, the element structure of the transistor shown in FIG. 3E-2 is similar to the structure of the bottom contact transistor shown in FIG. 6, but in the present invention, after the organic electronic material layer is formed, A source electrode and a drain electrode are provided in contact with each other. On the other hand, the element structure of the transistor shown in FIG. 2 (e-1) is similar to the structure of the top contact transistor shown in FIG. 4, but according to the method of the present invention, the source electrode and the drain electrode are formed. Since a spacer portion that defines a channel length exists on the organic electronic material layer when formed, a transistor having a short channel length can be easily formed. In addition, as shown in FIG. 3E-2, if the source electrode and the drain electrode are formed after the organic electronic material layer is removed by etching or the like, the electric resistance between the electrode and the channel can be reduced. . This is because the organic electronic material between the electrode and the channel is shortened as compared with the top contact type transistor.

  As described above, in the present invention, the problems of the conventional bottom contact type and top contact type transistors can be avoided, the charge movement in the current path can be made smooth, and high mobility can be realized stably.

  In addition, when the terms “upper” and “lower” are used as in the “lower” region or the “lower” region, the term “upper” indicates the direction in which the organic electronic material layer is located with respect to the substrate. “Down” intends the opposite direction. In addition to providing the spacer part directly on the organic electronic material layer, providing the spacer part on the organic electronic material layer provides the spacer part on the organic electronic material layer via a protective layer, for example. Including cases. The same applies to other members. Further, the “upper surface” of the spacer layer is intended to mean a surface on the “upper” side of the surface of the spacer layer, that is, a surface farther from the substrate. The same applies to other members.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the examples described below.

[Example 1]
A gate electrode 11 made of tantalum was formed on the glass substrate 10 by a normal photo process and sputtering. The thickness was 150 nm. Next, an anodic oxide film was formed as a gate insulating layer 12 on the gate electrode 11. Anodization was performed in a 1 wt% ammonium borate solution by treatment at 70 V for 50 minutes to a film thickness of 80 nm. Next, pentacene (manufactured by Aldrich) was deposited as the organic electronic material layer 13 to a film thickness of 60 nm by vacuum deposition. The substrate temperature at this time was 60 ° C.

    Then, the spacer part 30 was formed with the following procedures. First, an aqueous solution containing 20% by weight of polyvinyl alcohol and 0.5% by weight of ammonium bichromate was prepared and used as a photosensitive solution. This was coated on the pentacene thin film by a dip method so as to have a film thickness of 2.2 μm, and then dried at 60 ° C. for 10 minutes. The polyvinyl alcohol film thus formed was passed through a photomask and irradiated with ultraviolet rays for 3 minutes with a mercury lamp of 2.5 kW to cure the irradiated region. The portion where the source electrode and the drain electrode are formed was prevented from being irradiated with ultraviolet rays by a photomask. Then, the non-irradiated part was washed away with running water and developed.

    Thereafter, the polyvinyl alcohol film cured by oxygen plasma and the pentacene thin film exposed by development were simultaneously etched by about 10 nm. The channel length determined by the shape of the spacer portion was 30 μm, and the channel width was 100 μm. Thereafter, the sample was annealed in vacuum at 100 ° C. for 1 hour, and then the source electrode 15 and the drain electrode 14 were formed of a gold vapor deposition film. The gold film thickness was 80 nm.

The vapor deposition apparatus used for the above film formation was diffusion pump exhaust, and the vapor deposition was performed at a vacuum degree of 4 × 10 ⁻⁴ Pa (3 × 10 ⁻⁶ torr). Further, gold and pentacene were deposited by a resistance heating method at a film formation rate of 10 nm / sec and 0.4 nm / sec, respectively. The substrate temperature during film formation other than pentacene was room temperature.

[Example 2]
A sample of Example 2 was obtained in the same manner as Example 1 except that the channel length was 5 μm.

[Example 3]
A sample of Example 3 was obtained in the same manner as in Example 1 except that the thickness of the spacer portion was 1.1 μm.

[Example 4]
The etching depth of the organic electronic material after forming the spacer portion was reduced to the film thickness (ie 60 nm), and the same procedure as in Example 1 was performed except that the source electrode and the drain electrode were formed directly on the gate insulating layer. The sample of Example 4 was obtained.

[Example 5]
A sample of Example 5 was obtained in the same manner as in Example 1 except that the gate insulating layer 12 was formed by applying a polystryrene resin film by spin coating (thickness 150 nm).

[Example 6]
A sample of Example 6 was obtained in the same manner as in Example 1 except that the spacer portion 30 was formed and the electrodes 14 and 15 were provided as follows. That is, the means for forming the spacer portion forms a parylene film having a thickness of 1.1 μm on the pentacene thin film, and then a photoresist (OFPR-800, Tokyo Ohka Kogyo Co., Ltd.) is applied by spin coating to a thickness of 2.0 μm. After that, ultraviolet light of 405 nm and 11 mW / cm ² were irradiated for 4 seconds through a photomask to cure the irradiated portion. The portion where the source electrode and the drain electrode are formed is prevented from being irradiated with ultraviolet light by a photomask. Thereafter, the non-irradiated portion was washed away and developed with a developer (NMD-3 Tokyo Ohka Kogyo Co., Ltd.), and then pre-baked (110 ° C., 90 seconds) and post-baked (130 ° C., 30 minutes). Next, the parylene film exposed by oxygen plasma and the underlying pentacene film were etched. At this time, the cured photoresist is also etched by oxygen plasma, but the underlying parylene film is not etched due to the difference in film thickness.

[Example 7]
A sample of Example 7 was obtained in the same manner as in Example 1 except that etching with oxygen plasma was not performed.

[Comparative Example 1: Bottom contact type 1]
After forming the gate insulating layer, the source electrode and the drain electrode were formed using photolithography and vacuum evaporation, and then the sample of Comparative Example 1 was obtained in the same manner as in Example 1 except that the organic semiconductor material layer was formed. .

[Comparative Example 2: Bottom contact type 2]
A sample of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that the channel length was 5 μm.

[Comparative Example 3: Bottom contact type 3]
A sample of Comparative Example 3 was obtained in the same manner as in Example 1 except that the thickness of the spacer portion was 0.9 μm.

[Comparative Example 4: Top contact type 1]
A sample of Comparative Example 4 was obtained in the same manner as in Example 1 except that the spacer part was not formed and the source electrode and the drain electrode were directly formed on the gate insulating layer by vacuum deposition using a shadow mask.

[Comparative Example 5: Top contact type 2]
A sample of Comparative Example 5 was obtained in the same manner as Comparative Example 4 except that the channel length was 5 μm.

[Short-circuit probability, mobility]
Among the samples of Examples and Comparative Examples described above, in Comparative Example 3, a short circuit between the source electrode and the drain electrode was observed in three of the ten fabricated elements. Further, in Comparative Example 4, one of ten similarly fabricated elements and in Comparative Example 5 seven, a short circuit between the source electrode and the drain electrode was observed. Further, in Example 7, the mobility was relatively lowered. This is presumed to be a result of polyvinyl alcohol permeating into the pentacene grain boundary and increasing the contact resistance with the source electrode and the drain electrode.

  In other thin film transistor elements, p-channel type transistor operation was confirmed. Table 1 shows the mobility and the variation (standard deviation) obtained in each sample and the short circuit probability. In Examples 1 and 2, the mobility is remarkably improved as compared with Comparative Examples 1 and 2 having the same channel length, and the effect is particularly remarkable at a short channel length. In the case of Comparative Examples 4 and 5, the average value of the mobility is not significantly different from those of Examples 1 and 2 having the same channel length, but the standard deviation indicating the variation in characteristics is large. As described above, since short-circuiting increases with a short channel length, it is shown that the stability of the method of the present invention is superior to the conventional shadow mask method.

  As described above, according to the present invention, in the organic thin film transistor, the charge transfer between the source electrode, the drain electrode, and the channel on the gate insulating layer can be made smooth, and high mobility can be stably realized even in a short channel length. It was.

The conceptual diagram which showed the manufacturing method of the thin-film transistor concerning the 1st and 2nd embodiment of this invention is shown. The conceptual diagram which showed the manufacturing method of the thin-film transistor concerning the 1st Embodiment of this invention is shown. The conceptual diagram which showed the manufacturing method of the thin-film transistor concerning the 2nd Embodiment of this invention is shown. The conceptual diagram which showed typically the orientation of the crystal | crystallization of the organic electronic material in this invention is shown. FIG. 3 is a conceptual diagram illustrating an equivalent circuit for light-emitting element control using a thin film transistor. Sectional drawing of the conventional bottom contact type organic thin-film transistor is shown. Sectional drawing of the conventional top contact type organic thin-film transistor is shown. The conceptual diagram which showed typically the crystal orientation of the organic electronic material in a bottom contact type organic thin-film transistor is shown. The conceptual diagram which showed typically the growth state of the crystal | crystallization of the organic electronic material in a top contact type organic thin-film transistor when an organic electronic material is thin is shown.

Explanation of symbols

10, 110, 210: Substrate 11, 111, 211: Gate electrode 12, 112, 212: Gate insulating layer 13, 113, 213: Organic electronic material layer 14, 114, 214: Drain electrode,
15, 115, 215: source electrode,
16, 116, 216: Channel 20, 120, 220: Crystal of organic electronic material molecule 221: Surface of organic electronic material layer 222: Spatial defect of organic electronic material layer 24, 124, 224: Current in channel 30: Spacer Part

Claims (15)

A method for manufacturing a thin film transistor, comprising:
Providing a substrate;
Providing a gate electrode on the substrate;
Providing a gate insulating layer on the gate electrode;
Providing an organic electronic material layer on the gate insulating layer;
Providing a spacer portion in a gap region between the region where the source electrode is provided and the region where the drain electrode is provided on the organic electronic material layer;
Removing the organic electronic material layer in a region where the source electrode is provided and / or a region where the drain electrode is provided to a predetermined depth;
Providing a source electrode in a region where the source electrode is provided on the gate insulating layer and / or the organic electronic material layer;
Providing a drain electrode in a region where the drain electrode is provided on the gate insulating layer and / or the organic electronic material layer.   In the step of providing the source electrode, the source electrode is provided such that the upper surface of the source electrode is lower than the upper surface of the spacer portion, and in the step of providing the drain electrode, the upper surface of the drain electrode is The method according to claim 1, wherein the drain electrode is provided to be lower than an upper surface of the spacer portion. A method for manufacturing a thin film transistor, comprising:
Providing the substrate;
Providing a gate electrode on the substrate;
Providing a gate insulating layer on the gate electrode;
Providing an organic electronic material layer on the gate insulating layer;
Providing a spacer portion in a gap region between the region where the source electrode is provided and the region where the drain electrode is provided on the organic electronic material layer;
Providing a source electrode in a region where the source electrode is provided on the gate insulating layer and / or the organic electronic material layer so that an upper surface of the source electrode is lower than an upper surface of the spacer portion;
Providing a drain electrode in a region where the drain electrode is provided on the gate insulating layer and / or the organic electronic material layer such that an upper surface of the drain electrode is lower than an upper surface of the spacer portion; Including methods. Providing a spacer portion in the gap region,
Applying a photoresist material on the organic electronic material layer;
Of the coated photoresist material, the region where the source electrode is provided and the region where the drain electrode is provided are not irradiated with electromagnetic waves, but the gap regions are irradiated with electromagnetic waves, and the photoresist properties are applied in the gap regions. Curing the material;
Removing the uncured photoresist material. 5. A method according to any preceding claim.   The method according to claim 1, further comprising a step of providing a protective layer on the organic electronic material layer before the step of providing a spacer portion in the gap region. A thin film transistor,
A substrate,
A gate electrode provided on the substrate;
A gate insulating layer provided on the gate electrode;
A source electrode;
A drain electrode;
An organic electronic material layer provided at least in a gap region between the source electrode and the drain electrode on the gate insulating layer, wherein the organic electronic material layer includes the source electrode and / or the drain An organic electronic material having a smaller thickness of the organic electronic material layer in the region under the source electrode and / or the drain electrode than in the gap region, when further provided in the region under the electrode Layers,
And a spacer portion provided in the gap region on the organic electronic material layer. A thin film transistor,
A substrate,
A gate electrode provided on the substrate;
A gate insulating layer provided on the gate electrode;
A source electrode;
A drain electrode;
A gap region between the source electrode and the drain electrode on the gate insulating layer and an organic electronic material layer provided in a region under the source electrode and / or the drain electrode, the gap region An organic electronic material layer having a small thickness of the organic electronic material layer in a region under the source electrode and / or the drain electrode,
Thin film transistor. A thin film transistor,
A substrate,
A gate electrode provided on the substrate;
A gate insulating layer provided on the gate electrode;
A source electrode provided on the gate insulating layer;
A drain electrode provided on the gate insulating layer;
An organic electronic material layer provided in a gap region between the source electrode and the drain electrode on the gate insulating layer, wherein the organic electronic material layer includes a crystalline material, and the crystalline material is An organic electronic material layer oriented in substantially the same direction;
Thin film transistor.   The thin film transistor according to claim 7, further comprising a spacer portion provided in the gap region on the organic electronic material layer.   The method according to claim 6 or 9, wherein an upper surface of the spacer portion is higher than an upper surface of the source electrode and an upper surface of the drain electrode. A thin film transistor,
A substrate,
A gate electrode provided on the substrate;
A gate insulating layer provided on the gate electrode;
An organic electronic material layer provided on the gate insulating layer;
A source electrode provided on the organic electronic material layer;
A drain electrode provided on the organic electronic material layer;
A spacer portion provided in a gap region between the source electrode and the drain electrode on the organic electronic material layer, wherein an upper surface of the spacer portion is an upper surface of the source electrode and the drain electrode. A spacer part higher than the upper surface of
Thin film transistor.   The thin film transistor according to any one of claims 6 and 9 to 11, wherein the spacer portion has a thickness of 1 µm or more.   The thin film transistor according to any one of claims 6 and 9 to 12, further comprising a protective layer provided between the organic electronic material layer and the spacer portion.   The thin film transistor according to claim 6, wherein the organic electronic material layer includes a crystalline material. The thin film transistor according to claim 8 or 14, wherein the crystalline material is an acene compound represented by the following structural formula (I).

(In the formula, R is hydrogen, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an aryl group which may have a substituent, or an optionally substituted carbon group having 1 to 6 carbon atoms. An alkoxy group of

Alternatively, it represents a residue that forms an aromatic ring or a heterocyclic ring with an anthracene skeleton, and n represents an integer of 1 to 10. )

Images