WO2015033881A1 - Transistor organique en couches minces - Google Patents

Transistor organique en couches minces Download PDF

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Publication number
WO2015033881A1
WO2015033881A1 PCT/JP2014/072889 JP2014072889W WO2015033881A1 WO 2015033881 A1 WO2015033881 A1 WO 2015033881A1 JP 2014072889 W JP2014072889 W JP 2014072889W WO 2015033881 A1 WO2015033881 A1 WO 2015033881A1
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electrode
film transistor
thin film
organic
semiconductor layer
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PCT/JP2014/072889
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English (en)
Japanese (ja)
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昌弘 三谷
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シャープ株式会社
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K10/00—Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having a potential-jump barrier or a surface barrier
    • H10K10/40—Organic transistors
    • H10K10/46—Field-effect transistors, e.g. organic thin-film transistors [OTFT]
    • H10K10/462—Insulated gate field-effect transistors [IGFETs]
    • H10K10/466—Lateral bottom-gate IGFETs comprising only a single gate

Definitions

  • the present invention relates to an organic thin film transistor, and more particularly to an organic thin film transistor including an organic semiconductor layer as a semiconductor layer.
  • a thin film transistor is provided as a switching element for each pixel which is the minimum unit of an image.
  • an inorganic semiconductor material is mainly used, such as an oxide semiconductor such as amorphous silicon, polysilicon, or indium gallium zinc oxide.
  • an organic thin film transistor having an organic semiconductor layer formed of an organic semiconductor material has been proposed. Since the organic thin film transistor can be formed at a low temperature (less than 200 ° C.), the selectivity of the substrate is improved. In addition, since the organic semiconductor layer can be formed using a coating process, the manufacturing cost can be reduced. Furthermore, due to the flexibility of organic materials (such as organic semiconductors and organic insulating films) constituting the device, it is also suitable for flexible display devices.
  • JP-A-2004-55654 Patent Document 1
  • JP-A-2010-161312 Patent Document 2
  • Patent Document 2 disclose such organic thin film transistors.
  • An organic thin film transistor disclosed in Patent Document 1 includes a source electrode and a drain electrode arranged so as to be opposed to each other, and an organic semiconductor layer having carrier mobility formed between the source electrode and the drain electrode. Is provided.
  • the source electrode and the drain electrode are made of materials having different work functions.
  • An organic thin film transistor disclosed in Patent Document 2 includes a source electrode and a drain electrode that are arranged so as to be opposed to each other, and an organic semiconductor layer having carrier mobility formed between the source electrode and the drain electrode. Is provided.
  • a thiol compound layer made of a benzenethiol compound having an electron donating group bonded to a benzene ring is formed on a portion of the source electrode and the drain electrode that are in electrical contact with the organic semiconductor layer.
  • the degree of carrier injection from the source electrode into the organic semiconductor layer can be changed, and as a result, only the threshold voltage can be selectively controlled.
  • the TFT characteristics when the TFT characteristics are measured in the dark state after the light is turned on / off without applying a voltage in the photo state, the TFT characteristics hardly change. That is, in the organic thin film transistor, the characteristic shift occurs only when a voltage is applied while applying light, and the TFT characteristic changes very slowly with respect to the subsequent light blocking.
  • This phenomenon is very problematic when the organic thin film transistor is used as a backplane of a liquid crystal display device. This is because, in a liquid crystal display device, strong light hits an organic thin film transistor in a state where a voltage is applied by light from a backlight. Similarly, in an organic EL (Electro Luminescence) display device, light hits an organic thin film transistor in a state where a voltage is applied by self-luminescence.
  • organic EL Electro Luminescence
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide an organic thin film transistor that can easily extract charges accumulated in an organic semiconductor layer and has stable TFT characteristics. There is to do.
  • An organic thin film transistor includes a gate electrode, an organic semiconductor layer disposed to face the gate electrode, a gate insulating layer positioned between the gate electrode and the organic semiconductor layer, and the organic semiconductor layer. Connected to the organic semiconductor layer, and a body electrode connected to the organic semiconductor layer and for removing charges accumulated in the organic semiconductor layer.
  • the work function of the body electrode is preferably different from the work functions of the source electrode and the drain electrode.
  • the body electrode is preferably made of a material different from that of the source electrode and the drain electrode.
  • a monomolecular film is preferably formed at the interface between the body electrode and the organic semiconductor layer.
  • the organic semiconductor layer is preferably a p-type organic semiconductor layer.
  • the work function of the body electrode is the same as that of the source electrode or the drain electrode. It is preferably smaller than the work function.
  • the organic semiconductor layer is preferably an n-type organic semiconductor layer, and the work function of the body electrode is larger than the work function of the source electrode or the drain electrode. It is preferable.
  • the present invention it is possible to easily extract charges accumulated in the organic semiconductor layer and to provide an organic thin film transistor having stable TFT characteristics.
  • FIG. 1 is a plan view of an organic thin film transistor according to Embodiment 1.
  • FIG. 2 is a cross-sectional view corresponding to line II (A) -II (A) and a cross-sectional view corresponding to line II (B) -II (B) shown in FIG. 1 in a thin film transistor substrate including the organic thin film transistor shown in FIG.
  • FIG. 3 is a diagram showing a process of forming a pixel electrode, a source electrode terminal, and a body electrode terminal of the thin film transistor substrate shown in FIG. It is sectional drawing at the time of dividing
  • FIG. 20 is a diagram illustrating a process of forming a pixel electrode, a source electrode terminal, and a body electrode terminal of the thin film transistor substrate illustrated in FIG. 19.
  • FIG. 6 is a cross-sectional view when a thin film transistor substrate including an organic thin film transistor according to a fourth embodiment is divided along a direction in which source and drain electrodes are arranged, and a cross-sectional view when divided along an extending direction of a body electrode. It is a figure which shows the process of forming the source electrode of the thin-film transistor substrate shown in FIG. 29, a drain electrode, and a body electrode. It is a figure which shows the process of surface-treating to the body electrode shown in FIG.
  • FIG. 33 is a diagram showing a first step of forming a body electrode of the thin film transistor substrate shown in FIG. 32. It is a figure which shows the 2nd process of the process of forming the body electrode of the thin-film transistor substrate shown in FIG.
  • FIG. 33 is a diagram showing a step of forming a second protective layer and a gate insulating layer of the thin film transistor substrate shown in FIG. 32.
  • FIG. 33 is a diagram showing a step of forming a gate electrode of the thin film transistor substrate shown in FIG. 32.
  • FIG. 33 is a diagram showing a first step of forming an interlayer protective layer and an interlayer mask layer of the thin film transistor substrate shown in FIG. 32.
  • FIG. 33 is a diagram showing a second step of forming an interlayer protective layer and an interlayer mask layer of the thin film transistor substrate shown in FIG. 32.
  • FIG. 33 is a diagram showing a process of forming a pixel electrode, a source electrode terminal, and a body electrode terminal of the thin film transistor substrate shown in FIG. 32. It is sectional drawing at the time of dividing along the extending direction of a body electrode, and sectional drawing at the time of dividing the thin-film transistor substrate which comprises the organic thin-film transistor which concerns on Embodiment 6 along the direction where a source electrode and a drain electrode are arranged.
  • FIG. 33 is a diagram showing a first step of forming an interlayer protective layer and an interlayer mask layer of the thin film transistor substrate shown in FIG. 32.
  • FIG. 33 is a diagram showing a second step of forming an inter
  • FIG. 44 is a diagram showing a process of forming a source electrode, a drain electrode, and a body electrode of the thin film transistor substrate shown in FIG. 43.
  • FIG. 44 is a diagram showing a step of performing a surface treatment on the body electrode shown in FIG. 43. It is sectional drawing at the time of dividing along the extending direction of a body electrode, and sectional drawing at the time of dividing the thin-film transistor substrate which comprises the organic thin-film transistor concerning Embodiment 7 along the direction where a source electrode and a drain electrode are arranged.
  • FIG. 47 is a diagram showing a first step of forming an organic semiconductor layer of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a first step of forming a source electrode and a drain electrode of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a second step of forming the source electrode and the drain electrode of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a first step of forming a body electrode of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a second step of forming the body electrode of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a first step of forming a body electrode of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a step of forming a gate insulating layer of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a step of forming a gate electrode of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a first step of forming an interlayer protective layer and an interlayer mask layer of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a second step of forming the interlayer protective layer and the interlayer mask layer of the thin film transistor substrate shown in FIG. 46.
  • FIG. 47 is a diagram showing a process of forming a pixel electrode, a source electrode terminal, and a body electrode terminal of the thin film transistor substrate shown in FIG. 46.
  • FIG. 46 is a diagram showing a process of forming a pixel electrode, a source electrode terminal, and a body electrode terminal of the thin film transistor substrate shown in FIG. 46.
  • FIG. 9 is a cross-sectional view when a thin film transistor substrate including an organic thin film transistor shown in Embodiment 8 is divided along a direction in which a source electrode and a drain electrode are arranged, and a cross-sectional view when divided along an extending direction of a body electrode.
  • FIG. 59 is a diagram showing a process of forming a source electrode, a drain electrode, and a body electrode of the thin film transistor substrate shown in FIG. 58.
  • FIG. 60 is a diagram showing a step of performing a surface treatment on the body electrode shown in FIG. 59. It is a figure which shows the top view of the organic thin-film transistor which concerns on Embodiment 9.
  • FIG. It is a figure which shows the energy level of the organic thin-film transistor shown in FIG.
  • FIG. 64 is a diagram showing a first example of an equivalent circuit diagram of the liquid crystal display device shown in FIG. 63.
  • FIG. 64 is a diagram showing a second example of an equivalent circuit diagram of the liquid crystal display device shown in FIG. 63.
  • FIG. 67 is a diagram showing a first example of an equivalent circuit diagram of the organic EL display device shown in FIG. 66.
  • FIG. 67 is a diagram showing a second example of an equivalent circuit diagram of the organic EL display device shown in FIG. 66.
  • FIG. 64 is a diagram showing a second example of an equivalent circuit diagram of the organic EL display device shown in FIG. 66.
  • FIG. 67 is a diagram showing a third example of an equivalent circuit diagram of the organic EL display device shown in FIG. 66. It is a schematic sectional drawing which shows the 2nd form of the organic electroluminescence display which comprises the thin-film transistor substrate shown in FIG.
  • FIG. 71 is a diagram showing a first example of an equivalent circuit diagram of the organic EL display device shown in FIG. 70.
  • FIG. 1 is a plan view of the organic thin film transistor according to the first embodiment.
  • 2A and 2B are cross-sectional views corresponding to the line II (A) -II (A) shown in FIG. 1 and II (B) -II (II) in the thin film transistor substrate having the organic thin film transistor shown in FIG. B) It is sectional drawing corresponding to a line.
  • FIG. 1 FIG. 2 (A), and (B)
  • the organic thin-film transistor which concerns on this Embodiment, and the thin-film transistor substrate provided with the same are demonstrated.
  • an organic thin film transistor 1 includes a substrate 10, a base coat layer 11 formed so as to cover the main surface of the substrate 10, and a base coat.
  • the source electrode 14 a and the drain electrode 14 b are arranged side by side along a direction that is spaced apart from each other and intersects the direction in which the gate electrode 12 extends, and at least a part of the source electrode 14 a and the drain electrode 14 b sandwich the gate insulating layer 13. Are provided to overlap.
  • the source electrode 14a and the drain electrode 14b are parts for allowing a current to flow through the organic semiconductor layer 19a.
  • the body electrode 17a is disposed separately from the source electrode 14a and the drain electrode 14b, and is provided so as not to overlap the gate electrode 12.
  • the body electrode 17a is a part for removing charges accumulated in the organic semiconductor layer 19a.
  • the organic semiconductor layer 19a covers the body electrode 17a and a portion of the gate insulating layer 13 located between the source electrode 14a and the drain electrode 14b, and on the upper surface of each of the source electrode 14a, the drain electrode 14b, and the body electrode 17a. At least partly touches. A portion of the organic semiconductor layer 19a located between the source electrode 14a and the drain electrode 14b faces the gate electrode 12 so as to sandwich the gate insulating layer 13 therebetween.
  • the organic thin film transistor 1 further includes a protective layer 20a provided on the organic semiconductor layer 19a and a mask layer 21A provided on the protective layer 20a.
  • the thin film transistor substrate 2 is provided so as to cover the organic thin film transistor 1, the interlayer protective layer 22 provided so as to cover the organic thin film transistor 1, and the interlayer protective layer 22.
  • the interlayer mask layer 23A, the source electrode terminal 25a connected to the source electrode 14a of the organic thin film transistor 1, the pixel electrode 25b connected to the drain electrode 14b of the organic thin film transistor 1, and the body electrode 17a of the organic thin film transistor 1 are connected.
  • Body electrode terminal 25c is connected to cover the organic thin film transistor 1, the interlayer protective layer 22 provided so as to cover the organic thin film transistor 1, and the interlayer protective layer 22.
  • Contact holes 24a, 24b, and 24c are formed in the interlayer mask layer 23A and the interlayer protection layer 22.
  • the contact hole 24a is provided so as to reach the source electrode 14a from the surface side of the interlayer mask layer 23A.
  • the contact hole 24b is provided so as to reach the drain electrode 14b from the surface side of the interlayer mask layer 23A.
  • the contact hole 24c is provided so as to reach the body electrode 17a from the surface side of the interlayer mask layer 23A.
  • the source electrode terminal 25a is connected to the source electrode 14a via the contact hole 24a
  • the pixel electrode 25b is connected to the drain electrode 14b via the contact hole 24b
  • the body electrode terminal 25c is connected to the contact hole 24c. Is connected to the body electrode 17a.
  • the organic semiconductor layer 19a a p-type organic semiconductor layer or an n-type organic semiconductor layer can be employed.
  • the material of the source electrode, the drain electrode, and the body electrode can be appropriately selected. Details thereof will be described later.
  • FIG. 3 is a diagram illustrating an example of energy levels when the organic thin film transistor illustrated in FIG. 1 includes a p-type organic semiconductor layer.
  • HOMO of the organic semiconductor material Highest Occupied Molecular Orbital: highest occupied molecular orbital
  • the source electrode S source electrode 14a
  • the drain electrode D drain electrode 14b
  • LUMO of the organic semiconductor material forming a body electrode BD (body electrode 17a) using (Lowest Unoccupied Molecular Orbital lowest unoccupied molecular orbital) metallic material having a work function close W BD level. That is, the body electrode BD is formed by a different metal material as a source electrode S and the drain electrode D, the work function W BD of body electrode BD is the work function W S of the source electrode S and the drain electrode D, smaller than W D Become.
  • the organic thin-film transistor 1 of the present embodiment since the work function W S of the source electrode S is close to HOMO level of the organic semiconductor layer 19a, the hole of the p-type organic semiconductor It can be easily injected into the layer 19a. For this reason, a large current can flow in the organic thin film transistor 1. Further, since the work function W BD of the body electrode BD is lower than the LUMO level of the organic semiconductor layer 19a, electrons accumulated in the organic semiconductor layer 19a can be easily extracted through the body electrode BD. As a result, in the organic thin film transistor 1 according to the present embodiment, stable TFT characteristics can be realized by suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • FIG. 4 is a diagram illustrating an example of energy levels when the organic thin film transistor illustrated in FIG. 1 includes an n-type organic semiconductor layer.
  • the organic semiconductor layer 19a is n-type
  • LUMO of the organic semiconductor material Liwest Unoccupied Molecular Orbital: lowest unoccupied molecular orbital
  • the source electrode S source electrode 14a
  • the drain electrode D drain electrode 14b
  • the organic HOMO of the semiconductor material forming a body electrode BD (body electrode 17a) using a metal material having a (Highest Occupied Molecular Orbital highest occupied molecular orbital) near the level the work function W BD. That is, the body electrode BD is formed by a different metal material as a source electrode S and the drain electrode D, the work function W BD of body electrode BD is the work function W S of the source electrode S and the drain electrode D, greater than W D Become.
  • the work function W S of the source electrode S is smaller than the LUMO level of the organic semiconductor layer 19a, an electron of an n-type organic It can be easily injected into the semiconductor layer 19a. For this reason, a large current can flow in the organic thin film transistor 1.
  • the work function W BD of the body electrode BD is close to the HOMO level of the organic semiconductor layer 19a, holes accumulated in the organic semiconductor layer 19a can be easily extracted through the body electrode BD.
  • stable TFT characteristics can be realized by suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • FIGS. 5A and 5B to FIGS. 15A and 15B are diagrams showing respective steps for manufacturing the thin film transistor substrate shown in FIGS. 2A and 2B. With reference to FIGS. 5A and 5B to FIGS. 15A and 15B, a method of manufacturing the thin film transistor substrate 2 shown in FIGS. 2A and 2B will be described.
  • FIGS. 5A and 5B are diagrams showing a base coat layer forming step of the thin film transistor substrate 2 shown in FIGS. 2A and 2B.
  • a base coat layer 11 made of an inorganic insulating film, an organic insulating film, or a combination of both is formed on the substrate 10 for the purpose of barrier properties such as moisture and oxygen. To do.
  • a glass substrate a plastic substrate such as PEN, PES, or PET, or a substrate in which a film material such as PEN, PES, PET, PI, or aramid or an organic insulating film is formed on a glass substrate as a support substrate Etc.
  • a film material such as PEN, PES, PET, PI, or aramid or an organic insulating film is formed on a glass substrate as a support substrate Etc.
  • the base coat layer 11 can be formed by forming a nitride film, an oxide film, a nitrided oxide film or the like by, for example, a CVD method.
  • coating resin such as a polyimide and zeonore, for example by a spin coat method, a slit coat method, etc.
  • FIGS. 6 (A) and 6 (B) are diagrams showing a process of forming the gate electrode of the thin film transistor substrate shown in FIGS. 2 (A) and 2 (B).
  • the gate electrode 12 is formed to a thickness of about 100 to 400 nm by vacuum deposition, sputtering, or the like.
  • the gate electrode 12 can be formed by forming a metal film of Al, Al—Si, Cu, W, Mo, MoW, Ti, Cr, or the like and a metal film having a laminated structure in which these are laminated. .
  • an adhesion layer such as Ti or Cr at the interface.
  • the gate electrode 12 is formed using a vacuum evaporation method, a separate patterning step is not required by depositing the metal film using a metal mask.
  • the gate electrode 12 In the case of forming the gate electrode 12 using the sputtering method, first, the metal film (gate electrode film) is formed on the entire main surface of the base coat layer 11, and then a photosensitive resist is applied on the gate electrode film. . Thereafter, the photosensitive resist is patterned by photolithography (exposure / development). Subsequently, the gate electrode 12 is patterned by wet etching or dry etching of the gate electrode film using the photosensitive resist as a mask.
  • the pattern forming method of the gate electrode 12 is not limited to the above method, and a printing method using an electrically conductive paste, an electrolytic plating method, an electroless plating method, or the like can be employed.
  • FIGS. 7A and 7B are views showing a process of forming a gate insulating layer of the thin film transistor substrate shown in FIGS. 2A and 2B.
  • an organic insulating material such as polyvinylphenol (PVP) or polystyrene (PS) so as to cover the gate electrode 12 by spin coating, slit coating, ink jetting, printing, or the like.
  • PVP polyvinylphenol
  • PS polystyrene
  • FIGS. 8A and 8B are diagrams showing a process of forming a source electrode and a drain electrode of the thin film transistor substrate shown in FIGS. 2A and 2B.
  • the source electrode 14a and the drain electrode 14b are formed on the gate insulating layer 13 to a thickness of about 100 to 400 nm by vacuum deposition, sputtering, or the like.
  • the materials of the source electrode 14a and the drain electrode 14b are the same material, and can be selected according to the type of the organic semiconductor layer 19a formed in a later process.
  • the organic semiconductor layer 19a is p-type
  • a material having a large work function and a small hole injection barrier to the p-type organic semiconductor layer 19a is adopted as a material for the source electrode 14a and the drain electrode 14b.
  • a metal film of Pt, Rh, Au, Cu, Ag, Ta, W, Mo, MoW, MnO 2 , MnO 3 , Ni, Ti, Cr, or the like, and a metal film having a laminated structure in which these are laminated are combined. Can be adopted.
  • a material having a small work function and a small barrier for injecting electrons into the n-type organic semiconductor layer 19a may be employed as the material for the source electrode 14a and the drain electrode 14b.
  • a metal film of Na, Mg, Ca, Al, Ag, Cu, Au, W, Mo, MoW, Ni, Ti, Cr or the like and a metal film having a laminated structure in which these are laminated and combined can be employed. .
  • the material of the source electrode 14a and the drain electrode 14b is Al (work function: about 4.3 eV).
  • the electron injection barrier height is small (about ⁇ 0.2 eV)
  • electrons can be easily injected from the source electrode 14a to the organic semiconductor layer 19a, and a large current flows through the organic thin film transistor 1.
  • an adhesion layer such as Ti or Cr may be formed between the gate insulating layer 13 and the source electrode 14a and drain electrode 14b. Good.
  • the process of patterning separately by evaporating the said metal film using a metal mask becomes unnecessary.
  • the source electrode 14a and the drain electrode 14b are formed by sputtering, first, the metal film (source / drain electrode film) is formed over the entire main surface of the gate insulating layer 13. Then, a photosensitive resist is applied on the source / drain electrode film. Thereafter, the photosensitive resist is patterned by photolithography (exposure / development). Subsequently, the source electrode 14a and the drain electrode 14b are patterned by performing wet etching or dry etching on the gate electrode film using the photosensitive resist as a mask.
  • the pattern forming method of the source electrode 14a and the drain electrode 14b is not limited to the above method, and a printing method, an electroplating method, an electroless plating method, or the like using a conductive paste can be employed.
  • FIGS. 9A, 9B, 10A, and 10B show the first and second steps of the process of forming the body electrode of the thin film transistor substrate shown in FIGS. 2A and 2B.
  • FIG. 9A, 9B, 10A, and 10B show the first and second steps of the process of forming the body electrode of the thin film transistor substrate shown in FIGS. 2A and 2B.
  • FIG. 9A and 9B When the body electrode 17a is formed by using the sputtering method and the lift-off method, first, as shown in FIGS. 9A and 9B, the gate insulating layer 13 is formed so as to cover the source electrode 14a and the drain electrode 14b. After the positive photosensitive resist 15 is applied to the entire surface on the main surface, only the region where the body electrode 17a is to be formed is exposed and developed to remove the photosensitive resist 15.
  • the cross-sectional shape of the photosensitive resist 15 is desirably a reverse taper type so that the photosensitive resist 15 can be easily lifted off after the body electrode film 17 is formed. Other regions except the region where the body electrode 17a is to be formed are protected by the photosensitive resist 15.
  • the body electrode film 17 is formed to a thickness of about 100 to 400 nm on the entire surface of the substrate on which the photosensitive resist 15 has been formed by sputtering. Subsequently, as shown in FIGS. 10A and 10B, the body resist 17 is formed on the gate insulating layer 13 by removing the photosensitive resist 15 used as the deposition mask by lifting off with a stripping solution.
  • an adhesion layer such as Ti or Cr may be formed between the gate insulating layer 13 and the body electrode 17a.
  • the material of the body electrode 17a can be selected according to the type of the organic semiconductor layer 19a and the material of the source electrode 14a and the drain electrode 14b.
  • the material of the body electrode 17a is selected from the source electrode 14a and the drain electrode 14b. It is desirable to use a material having a small work function, and a laminated structure in which metal films such as Na, Mg, Ca, Al, Ag, Cu, Au, W, Mo, MoW, Ni, Ti, and Cr are laminated and combined. The metal film can be used.
  • pentacene (HOMO level: about 5.3 eV) is adopted as the material of the p-type organic semiconductor layer 19a
  • Au work function: about 5.0 eV
  • Ca (work function: about 2.9 eV) can be used as the material of the body electrode 17a.
  • the organic semiconductor layer is interposed via the body electrode 17a.
  • the electrons accumulated in 19a can be easily extracted.
  • stable TFT characteristics can be realized by suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • the material of the body electrode 17a is selected from the source electrode 14a and the drain electrode 14b in order to extract holes accumulated in the n-type organic semiconductor layer 19a by light irradiation. It is desirable to use a material having a large work function, such as Pt, Rh, Au, Cu, Ag, Ta, Al, W, Mo, MoW, MnO 2 , MnO 3 , Ni, Ti, Cr, etc.
  • a metal film having a laminated structure in which the layers are stacked and combined can be employed.
  • C60 fullerene (HOMO level: about 6.2 eV, LUMO level: about 4.5 eV) is adopted as the material of the n-type organic semiconductor layer 19a, and Al is used as the material of the source electrode 14a and the drain electrode 14b.
  • Pt (work function: about 5.7 eV) can be employed as the material of the body electrode 17a.
  • the organic semiconductor layer is interposed via the body electrode 17a.
  • the holes accumulated in 19a can be easily extracted.
  • stable TFT characteristics can be realized by suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • the process of patterning separately by evaporating the said metal film using a metal mask becomes unnecessary.
  • the pattern formation method of the body electrode 17a is not limited to the above method, and a printing method, an electroplating method, an electroless plating method, or the like using a conductive paste can be employed.
  • FIGS. 11A and 11B and FIGS. 12A and 12B show the first step of forming the organic semiconductor layer, protective layer, and mask layer of the thin film transistor substrate shown in FIGS. It is a figure which shows a 2nd process.
  • first, spin coating, slit coating is performed.
  • the organic semiconductor film 19 is formed on the entire substrate on which the source electrode 14a, the drain electrode 14b, and the body electrode 17a are formed using a method, an inkjet method, a printing method, a vapor deposition method, or the like.
  • the organic semiconductor film 19 is formed with a thickness of about 40 to 200 nm.
  • a protective film 20 made of an inorganic insulating film, an organic insulating film, or a laminated film combining these is formed on the organic semiconductor film 19 using the above method.
  • the organic insulating film 21 for forming the mask layer 21A is formed on the protective film 20 using the above method.
  • the protective film 20 and the organic insulating film 21 are each formed with a thickness of about 40 to 1000 nm.
  • pentacene As a material for the p-type organic semiconductor film 19 (organic semiconductor layer 19a), pentacene, soluble pentacene, TIPS pentacene, P3HT (Poly [3-hexyltiophene-2,5-diyl]), copper phthalocyanine, or the like may be employed. It can.
  • examples of the material of the n-type organic semiconductor film 19 (organic semiconductor layer 19a) include perylene diimide derivatives, C60 fullerene, fullerene derivatives, PCBM ([6,6] -Phenyl-C61-Butyric Acid Methyl Ester), SIMEF (Silylmethyl [ 60] fullerene) etc. can be adopted.
  • a nitride film, an oxide film, a nitrided oxide film, or the like can be employed when an inorganic insulating film is used, and when an organic insulating film is used.
  • Parylene, CYTOP (registered trademark) manufactured by Asahi Glass Co., Ltd., or the like can be used.
  • CYTOP registered trademark manufactured by Asahi Glass Co., Ltd., or the like
  • the organic insulating film 21 for example, a negative organic insulating film can be adopted.
  • the organic insulating film 21 has photosensitivity, and a part thereof functions as a mask.
  • the organic insulating film 21 is exposed and developed using a light shielding mask 82. At this time, the portion of the organic insulating film 21 that has been exposed to light that has passed through the opening 82a provided in the light shielding mask 82 is cured to become the mask layer 21A and remains on the protective film 20 after development.
  • the portion 21B of the organic insulating film 21 that has not been exposed to light is melted by development.
  • the organic semiconductor film 19 and the protective film 20 are collectively etched and patterned, whereby the organic semiconductor layer 19a, the protective layer 20a, and the mask are formed in an island shape as shown in FIGS. Layer 21A is formed.
  • the stacked body of the organic semiconductor layer 19a, the protective layer 20a, and the mask layer 21A is separated from the source electrode 14a and the drain electrode 14b that are arranged to face each other. It is formed so as to cover a part of the formed body electrode 17a.
  • Dry etching is performed using SF6, CHF3, CF4, O2, Ar, or a combination of these gases.
  • the protective layer 20a and the mask layer 21A are left as they are without ashing or the like in order to avoid damage to the organic semiconductor layer 19a due to ashing or the like.
  • the organic thin film transistor 1 according to the present embodiment can be manufactured through the above steps.
  • FIGS. 13A and 13B and FIGS. 14A and 14B show the first step of forming the interlayer protective layer and the interlayer mask layer of the thin film transistor substrate shown in FIGS. 2A and 2B. It is a figure which shows a 2nd process. As shown in FIGS. 13A and 13B and FIGS.
  • the interlayer protective layer 22 and the interlayer mask layer 23A when forming the interlayer protective layer 22 and the interlayer mask layer 23A, first, spin coating, slit coating, Interlayer protection composed of an inorganic insulating film, an organic insulating film, or a laminated film combining these over the entire substrate on which the organic semiconductor layer 19a, the protective layer 20a, and the mask layer 21A are formed using an inkjet method, a printing method, a vapor deposition method, or the like. Layer 22 is formed. Subsequently, the organic insulating film 23 for forming the interlayer mask layer 23A is formed on the interlayer protective layer 22 by using the above method.
  • the interlayer protective layer 22 and the organic insulating film 23 are each formed with a thickness of about 200 to 1000 nm.
  • the interlayer protective layer 22 As a material for forming the interlayer protective layer 22, when using an inorganic insulating film, a nitride film, an oxide film, a nitrided oxide film, or the like can be adopted. When using an organic insulating film, parylene, Asahi Glass Co., Ltd. CYTOP (registered trademark) or the like can be used, and a combination of these inorganic insulating films and organic insulating films can also be used.
  • the organic insulating film 23 for example, a negative organic insulating film can be adopted.
  • the organic insulating film 23 has photosensitivity, and a part thereof functions as a mask.
  • the organic insulating film 23 is exposed and developed using a light shielding mask 81.
  • the portion of the organic insulating film 23 that has been exposed to light that has passed through the opening 81a provided in the light shielding mask 81 is cured to become the interlayer mask layer 23A, and remains on the interlayer protective layer 22 after development.
  • the portion 23B of the organic insulating film 23 that was not exposed to light is melted by development.
  • the light shielding mask 81 shields the region of the organic insulating film 23 where the contact holes 24a, 24b, 24c are formed and the region where the contact hole (not shown) reaching the gate electrode 12 is formed.
  • FIGS. 15A and 15B are diagrams showing a process of forming a pixel electrode, a source electrode terminal, and a body electrode terminal of the thin film transistor substrate shown in FIGS. 2A and 2B.
  • a source electrode terminal 25a, a pixel electrode 25b, and a body electrode terminal 25c are formed by vacuum deposition, sputtering, or the like.
  • the source electrode terminal 25a, the pixel electrode 25b, and the body electrode terminal 25c may be formed of the same material or different materials.
  • a conductive film such as Au, Ag, Cu, Al, or Mo, or a transparent conductive film such as IZO, ITO, CNT, or graphene can be used.
  • a transparent conductive film such as IZO, ITO, ZnO, or SnO for the pixel electrode 25b in order to extract light from the opening.
  • a reflective electrode such as Al, Al alloy, Ag, or Ag alloy is used for the pixel electrode 25b in order to extract light from the upper portion, or IZO, ITO, or the like is used as an upper layer.
  • a laminated structure electrode in which a transparent conductive film and a reflective electrode made of Al, Al alloy, Ag, Ag alloy, Mo, Cr or the like are combined in the lower layer.
  • the transparent conductive film is formed on the entire substrate on which the interlayer mask layer 23A is formed, and the transparent conductive film is patterned into a predetermined pattern, whereby the source electrode terminal 25a and the pixel electrode are formed. 25b and body electrode terminal 25c are formed.
  • a separate patterning process is not required by depositing the metal film using a metal mask.
  • the source electrode terminal 25a, the pixel electrode 25b, and the body electrode terminal 25c are formed by using a spin coating method, a slit coating method, an ink jet method, a printing method, or the like, as materials for forming these, Au, An ink containing nanoparticles such as Ag, Cu, Al, ITO, CNT, and graphene can be employed.
  • the source electrode terminal 25a, the pixel electrode 25b, and the body electrode terminal 25c are each formed with a thickness of about 100 to 600 nm.
  • a gate electrode terminal (not shown) may be formed simultaneously with the source electrode terminal 25a, the pixel electrode 25b, and the body electrode terminal 25c so as to cover the surface of the contact hole reaching the gate electrode 12 with the same material. .
  • the thin film transistor substrate 2 including the organic thin film transistor 1 having a bottom gate-bottom contact structure can be manufactured.
  • the body electrode 17a is formed of a material different from that of the source electrode 14a and the drain electrode 14b, so that the source electrode 14a and the drain electrode 14b are formed.
  • the work function and the work function of the body electrode 17a are different.
  • liquid crystal display panel or an organic EL panel using the thin film transistor substrate 2, a liquid crystal panel or an organic EL panel having a stable display quality that is hardly affected by light such as backlight, external light, and self-light emission. Can be obtained.
  • the organic thin film transistor 1 according to the present embodiment has a bottom contact structure in which the source electrode 14a and the drain electrode 14b are formed before the organic semiconductor layer 19a is formed, the source electrode 14a and the drain electrode 14b are formed.
  • photolithography can be used instead of the lift-off method. For this reason, the organic thin-film transistor 1 with a short channel length can be manufactured, and a high-definition display and a fine device can be manufactured using this.
  • FIGS. 16A and 16B are a cross-sectional view and a body electrode extending direction when the thin film transistor substrate including the organic thin film transistor according to the second embodiment is divided along the direction in which the source electrode and the drain electrode are arranged. It is sectional drawing at the time of dividing along.
  • FIGS. 16A and 16B an organic thin film transistor 1A according to the present embodiment and a thin film transistor substrate 2A including the same will be described.
  • 16A shows a portion corresponding to FIG. 2A
  • FIG. 16B shows a portion corresponding to FIG. 2B.
  • the organic thin film transistor 1A according to the present embodiment and the thin film transistor substrate 2A having the same are the organic thin film transistor 1 according to the first embodiment and the thin film transistor substrate 2 having the same.
  • the body electrode 17b When the body electrode 17b is subjected to a surface treatment, the body electrode 17b has a work function different from that of the source electrode 14a and the drain electrode 14b. It is the same.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of the same metal material, and an SAM (Self Align Monolayer) film (self) is formed on the interface between the body electrode 17b and the organic semiconductor layer 19a.
  • An organized monolayer 93) is formed. Even when the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of the same metal material, the source electrode 14a and the self-assembled monolayer 93 are formed so as to cover the surface of the body electrode 17b.
  • the work function of the drain electrode 14b and the work function of the body electrode 17b can be made different.
  • the self-assembled monolayer 93 can be selected according to the type of the organic semiconductor layer 19a.
  • MBT 4-Methyl Benzene Thiol
  • a metal material having a work function close to the HOMO (Highest Occupied Molecular Orbital) level of the organic semiconductor material is adopted as the material of the source electrode 14a, the drain electrode 14b, and the body electrode 17b.
  • the work function of the body electrode 17b is the same as that of the source electrode 14a and It becomes smaller than the work function of the drain electrode 14b.
  • HBT 4-Hydroxy Benzene Thiol
  • FBT Fluoro Benzene Thiol
  • a metal material having a work function close to the LUMO (Lowest Unoccupied Molecular Orbital) level of the organic semiconductor material is adopted as the material of the source electrode 14a, the drain electrode 14b, and the body electrode 17b.
  • the work function of the body electrode 17b Becomes larger than the work functions of the source electrode 14a and the drain electrode 14b.
  • the surface of the body electrode 17b is subjected to plasma treatment and UV treatment.
  • the work function of the body electrode 17b can be made different from that of the source electrode 14a and the drain electrode 14b.
  • the method for manufacturing the thin film transistor substrate according to the present embodiment basically conforms to the method for manufacturing the thin film transistor substrate 2 according to the first embodiment, and has a surface treatment step, so that the thin film transistor substrate 2 according to the first embodiment. This is different from the manufacturing method.
  • the method of manufacturing the organic thin film transistor 1A according to the present embodiment first, in the step of forming the base coat layer, the step of forming the gate electrode, and the step of forming the gate insulating layer, the thin film transistor substrate according to the first embodiment
  • the base coat layer 11, the gate electrode 12, and the gate insulating layer 13 are formed on the substrate 10 by performing the same process as in the manufacturing method 2.
  • FIGS. 17A and 17B are diagrams showing a process of forming a source electrode, a drain electrode, and a body electrode of the thin film transistor substrate shown in FIGS. 16A and 16B.
  • a source electrode 14a, a drain electrode 14b, and a body electrode 17b patterned in a predetermined shape by a vacuum deposition method, a sputtering method, or the like are gated to a thickness of about 100 to 400 nm. It is formed on the insulating layer 13.
  • the materials of the source electrode 14a, the drain electrode 14b, and the body electrode 17b are the same material, and can be selected according to the type of the organic semiconductor layer 19a.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of a material having a high work function and a small hole injection barrier to the p-type organic semiconductor layer 19a.
  • the metal film can be used.
  • the material of the source electrode 14a, the drain electrode 14b, and the body electrode 17b is Au (work function: about 5.0 eV) can be employed.
  • the hole injection barrier height is small (about 0.3 eV)
  • holes can be easily injected into the organic semiconductor layer 19a from the source electrode 14a and the drain electrode 14b, and the organic thin film transistor 1A can be injected. A large current can flow.
  • the material for the source electrode 14a, the drain electrode 14b, and the body electrode 17b is a material having a small work function and a small barrier for electron injection into the n-type organic semiconductor layer 19a. It is preferable to adopt metal films such as Na, Mg, Ca, Al, Ag, Cu, Au, W, Mo, MoW, Ni, Ti, and Cr, and a metal film having a laminated structure in which these are stacked and combined. can do.
  • the material of the source electrode 14a, the drain electrode 14b, and the body electrode 17b is Au (work function: About 4.5 eV) can be employed.
  • the electron injection barrier height is small (about 0.5 eV)
  • electrons can be easily injected into the organic semiconductor layer 19a from the source electrode 14a and the drain electrode 14b, and a large current flows into the organic thin film transistor 1A. Can flow.
  • Ti, Cr are interposed between the gate insulating layer 13 and the source electrode 14a, drain electrode 14b, and body electrode 17b.
  • An adhesive layer such as
  • the process of patterning separately by evaporating the said metal film using a metal mask becomes unnecessary.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are formed by sputtering, first, the above metal film (source / drain / body electrode film) is formed over the entire main surface of the gate insulating layer 13. ), A photosensitive resist is applied on the source / drain / body electrode film. Thereafter, the photosensitive resist is patterned by photolithography (exposure / development). Subsequently, the source electrode 14a, the drain electrode 14b, and the body electrode 17b are patterned by wet etching or dry etching of the gate electrode film using the photosensitive resist as a mask.
  • the dry etching is performed using SF 6 , CHF 3 , CF 4 , Ar gas, and a combination thereof. After the etching, the photosensitive resist used as a mask is removed with a stripping solution. Thereby, the source electrode 14a and the drain electrode 14b are formed.
  • the pattern forming method of the source electrode 14a, the drain electrode 14b, and the body electrode 17b is not limited to the above method, and a printing method, an electroplating method, an electroless plating method, or the like using a conductive paste may be employed. it can.
  • FIGS. 18 (A) and 18 (B) are diagrams showing a step of performing a surface treatment on the body electrode shown in FIGS. 17 (A) and 17 (B).
  • the step of performing the surface treatment on the body electrode 17b first, the entire surface of the substrate 10 on which the source electrode 14a, the drain electrode 14b, and the body electrode 17b are formed is exposed to light. After the application of the resist 16, the resist is patterned by photolithography (exposure / development) so that only the surface of the body electrode 17b is exposed. Subsequently, a self-assembled monolayer 93 is applied to the entire surface of the substrate 10 on which the patterned photosensitive resist 16 is formed, and only the work function of the body electrode 17b is changed.
  • the resist is stripped with a stripping solution to remove the photosensitive resist 16 and the self-assembled monolayer 93 applied on the photosensitive resist 16.
  • the self-assembled monomolecular film 93 is formed so as to cover the surface of the body electrode 17b, and the work function of the body electrode 17b can be changed.
  • only the work function of the body electrode 17b may be changed by dropping the self-assembled monolayer 93 only in the body electrode 17b region by an ink jet method instead of the photolithography method.
  • resist coating or patterning by photolithography is not required, and the self-assembled monomolecular film can be directly formed so as to cover the surface of the body electrode 17b, so that the number of masks can be reduced. Thereby, manufacturing cost can be reduced.
  • the work function of the body electrode 17b is desirably smaller than the work functions of the source electrode 14a and the drain electrode 14b in order to extract accumulated electrons.
  • MBT 4-Methyl Benzene Thiol
  • the self-assembled monolayer 93 that reduces the work function.
  • the work function of the electrode (Au) can be reduced from about 5.0 eV to about 4.3 eV.
  • the work function of the body electrode (Cu) can be reduced from 4.7 eV to about 4.0 eV.
  • the work function of the body electrode 17b can be reduced to a value close to the LUMO level (about 3.5 eV) of pentacene, which is the p-type organic semiconductor layer 19a, so that the organic semiconductor layer 19a is interposed via the body electrode 17b.
  • the electrons accumulated inside can be easily extracted. Thereby, stable TFT characteristics can be realized while suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • the work function of the body electrode 17b is preferably larger than the work functions of the source electrode 14a and the drain electrode 14b in order to extract accumulated holes.
  • HBT 4-Hydroxy Benzene Thiol
  • FBT Fluoro Benzene Thiol
  • the drain electrode 14b and the body electrode 17b HBT or FBT is applied to the surface of the body electrode 17b.
  • the work function of the body electrode (Au) can be increased from about 5.0 eV to about 5.2 eV.
  • the body electrode 17b when C60 fullerene is used as the n-type organic semiconductor material and Al is used as the material of the source electrode 14a, the drain electrode 14b, and the body electrode 17b, HBT or FBT is used as the surface of the body electrode 17b.
  • the work function of the body electrode (Al) can be increased from 4.3 eV to 4.5 eV.
  • the work function of the body electrode 17b can be brought close to the HOMO level (about 6.2 eV) of C60 fullerene, which is the n-type organic semiconductor layer 19a, so that it is accumulated in the organic semiconductor layer 19a via the body electrode 17b. Holes can be easily extracted. Thereby, stable TFT characteristics can be realized while suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • the same process as that of the method for manufacturing the thin film transistor substrate according to the first embodiment is performed, thereby providing the organic thin film transistor 1A according to the present embodiment. Can be manufactured.
  • the same process as the method for manufacturing the thin film transistor substrate 2 according to the first embodiment is performed.
  • the thin film transistor substrate 2A including the organic thin film transistor 1A having the bottom gate-bottom contact structure can be manufactured.
  • the surface is formed only on the surface of the body electrode 17b.
  • the work functions of the source electrode 14a and the drain electrode 14b are different from the work function of the body electrode 17a.
  • the body electrode 17b can be formed from the same material as the source electrode 14a and the drain electrode 14b, thereby reducing the number of processes and material costs. Manufacturing cost can be reduced.
  • FIGS. 19A and 19B are a cross-sectional view and a body electrode extending direction when the thin film transistor substrate including the organic thin film transistor according to the third embodiment is divided along the direction in which the source electrode and the drain electrode are arranged. It is sectional drawing at the time of dividing along.
  • FIGS. 19A and 19B an organic thin film transistor 1B according to the present embodiment and a thin film transistor including the same will be described.
  • FIG. 19A shows a portion corresponding to FIG. 2A
  • FIG. 19B shows a portion corresponding to FIG.
  • the organic thin film transistor 1B according to the present embodiment and the thin film transistor substrate 2B having the same are the organic thin film transistor 1 according to the first embodiment and the thin film transistor substrate 2 having the same. Is different in that the source electrode 14a and the drain electrode 14b have a top contact structure instead of a bottom contact structure, and a protective layer and a mask layer are not formed accordingly. It is almost the same.
  • the organic thin film transistor 1B includes a substrate 10, a base coat layer 11 formed so as to cover the main surface of the substrate 10, a gate electrode 12 formed on the base coat layer 11, A gate insulating layer 13 formed on the base coat layer 11 so as to cover the gate electrode 12; an organic semiconductor layer 19a disposed on the gate insulating layer 13 so as to face the gate electrode 12 so as to sandwich the gate insulating layer 13; A source electrode 14a, a drain electrode 14b, and a body electrode 17a formed on the gate insulating layer 13 so as to be connected to the upper surface of the organic semiconductor layer 19a.
  • the source electrode 14 a and the drain electrode 14 b are arranged side by side along a direction that is spaced apart from each other and intersects the direction in which the gate electrode 12 extends, and at least a part of the source electrode 14 a and the drain electrode 14 b sandwich the gate insulating layer 13. Are provided to overlap.
  • the source electrode 14a and the drain electrode 14b are parts for allowing a current to flow through the organic semiconductor layer 19a.
  • the body electrode 17a is disposed separately from the source electrode 14a and the drain electrode 14b, and is provided so as not to overlap the gate electrode 12.
  • the body electrode 17a is a part for removing charges accumulated in the organic semiconductor layer 19a.
  • the body electrode 17a with a material different from that of the source electrode 14a and the drain electrode 14b, the work function of the source electrode 14a and the drain electrode 14b is different from the work function of the body electrode 17a.
  • the manufacturing method of the thin film transistor substrate 2B according to the present embodiment is basically the same as the manufacturing method of the thin film transistor substrate 2 according to the first embodiment, and the organic semiconductor is formed before the step of forming the source electrode 14a and the drain electrode 14b.
  • the difference is that the step of forming the layer 19a is provided and the step of forming a protective layer and a mask layer on the organic semiconductor layer 19a is not provided.
  • the method of manufacturing the organic thin film transistor 1B according to the present embodiment first, in the step of forming the base coat layer, the step of forming the gate electrode, and the step of forming the gate insulating layer, the thin film transistor substrate according to the first embodiment
  • the base coat layer 11, the gate electrode 12, and the gate insulating layer 13 are formed on the substrate 10 by performing the same process as in the manufacturing method 2.
  • FIGS. 20A and 20B and FIGS. 21A and 21B are a first step and a second step of the step of forming the organic semiconductor layer of the thin film transistor substrate shown in FIGS. FIG.
  • a source electrode is formed using a spin coating method, a slit coating method, an ink jet method, a printing method, a vapor deposition method, or the like.
  • the organic semiconductor film 19 is formed to a thickness of 40 to 200 nm on the entire substrate on which the drain electrode 14b, the body electrode 17a, and the drain electrode 14b are formed.
  • the p-type organic semiconductor film 19 (organic semiconductor layer 19a)
  • pentacene for example, pentacene, soluble pentacene, TIPS pentacene, P3HT (Poly [3-hexyltiophene-2,5-diyl]), copper phthalocyanine, or the like is employed.
  • P3HT Poly [3-hexyltiophene-2,5-diyl]
  • copper phthalocyanine or the like is employed.
  • Examples of the material of the n-type organic semiconductor film 19 (organic semiconductor layer 19a) include perylene diimide derivatives, C60 fullerene, fullerene derivatives, PCBM ([6,6] -Phenyl-C61-Butyric Acid Methyl Ester), SIMEF (Silylmethyl [ 60] fullerene) etc. can be adopted. In the present embodiment, for example, it is preferable to employ C60 fullerene having excellent chemical resistance.
  • the photosensitive resist 26 is applied to the entire substrate 10 on which the organic semiconductor film 19 is formed, the photosensitive resist 26 is patterned by photolithography (exposure / development), and the region where the organic semiconductor film 19 is to be islanded is formed.
  • the photosensitive resist 26 is formed only on the top.
  • the organic semiconductor layer 19 is formed in an island shape on the gate insulating layer 13 by performing patterning by etching the organic semiconductor film 19.
  • Dry etching is performed using a gas such as SF 6 , CHF 3 , CF 4 , Cl 2 , O 2 , Ar, or a combination thereof. Subsequently, the entire substrate 10 is immersed in a stripping solution, and the upper surface of the organic semiconductor layer 19a is exposed by removing the photosensitive resist 26 on the organic semiconductor layer 19a.
  • a gas such as SF 6 , CHF 3 , CF 4 , Cl 2 , O 2 , Ar, or a combination thereof.
  • 22A, 22B, 23A, and 23B show a first step and a first step of forming the source electrode and the drain electrode of the thin film transistor substrate shown in FIGS. 19A and 19B. It is a figure which shows 2 processes.
  • a positive type photosensitive film is formed on the entire substrate 10 on which the organic semiconductor layer 19a is formed.
  • a conductive resist 27 is applied.
  • the cross-sectional shape of the photosensitive resist 27 is desirably a reverse taper type so that the photosensitive resist 27 can be easily lifted off after the source / drain electrode film 14 is formed.
  • Other regions except the region where the source electrode 14a and the drain electrode 14b are formed are protected with a photosensitive resist 27.
  • the source / drain electrode film 14 is formed to a thickness of about 100 to 400 nm on the entire substrate 10 patterned with the photosensitive resist 27 by sputtering. At this time, a part of the source / drain electrode film 14 is cut by the step of the photosensitive resist pattern, so that the source / drain electrode film 14 is in contact with the end of the upper surface of the organic semiconductor layer 19a.
  • the photosensitive resist 27 used as a deposition mask is removed by lifting off with a stripping solution. Thereby, the source electrode 14a and the drain electrode 14b are formed.
  • the present invention is not limited to this, and is not limited thereto.
  • the source electrode 14a and the drain electrode 14b may be formed using a method or the like.
  • the organic semiconductor layer 19a is p-type
  • a material having a large work function and a small hole injection barrier to the p-type organic semiconductor layer 19a is adopted as a material for the source electrode 14a and the drain electrode 14b.
  • Pt, Rh, Au, Cu, Ag, Ta, W, Mo, MoW, MnO2, MnO3, Ni, Ti, Cr, etc., and a metal film having a laminated structure in which these are laminated are employed. be able to.
  • a material having a small work function and a small barrier for injecting electrons into the n-type organic semiconductor layer 19a may be employed as the material for the source electrode 14a and the drain electrode 14b.
  • a metal film of Na, Mg, Ca, Al, Ag, Cu, Au, W, Mo, MoW, Ni, Ti, Cr or the like and a metal film having a laminated structure in which these are laminated and combined can be employed. .
  • the material of the source electrode 14a and the drain electrode 14b is Al (work function: about 4.3 eV).
  • the electron injection barrier height is small (about ⁇ 0.2 eV)
  • electrons can be easily injected from the source electrode 14a and the drain electrode 14b into the organic semiconductor layer 19a, which is large in the organic thin film transistor 1B. Current can flow.
  • a thin oxide film layer of about several nm is formed between the source electrode 14a and the drain electrode 14b and the organic semiconductor layer 19a. May be.
  • FIGS. 24A, 24B, 25A, and 25B show the first and second steps of forming the body electrode of the thin film transistor substrate shown in FIGS. 19A and 19B.
  • FIG. As shown in FIGS. 24A and 24B and FIGS. 25A and 25B, in the first step and the second step of forming the body electrode 17a, the thin film transistor according to the first embodiment is manufactured.
  • the body electrode 17a whose tip is in contact with the upper surface of the organic semiconductor layer 19a is formed by performing a process substantially similar to the method. Thereby, the organic thin-film transistor 1B which concerns on this Embodiment can be manufactured.
  • the material of the body electrode 17a is selected from the source electrode 14a and the drain electrode 14b. It is desirable to use a material having a small work function, and a laminated structure in which metal films such as Na, Mg, Ca, Al, Ag, Cu, Au, W, Mo, MoW, Ni, Ti, and Cr are laminated and combined. The metal film can be used.
  • copper phthalocyanine (HOMO level: about 5.0 eV) is adopted as the material of the p-type organic semiconductor layer 19a
  • Au work function: about 5.0 eV
  • Ca (work function: about 2.9 eV) can be adopted as the material of the body electrode 17a.
  • the work function (about 2.9 eV) of the body electrode 17a is lower than the LUMO level (about 3.5 eV) of the organic semiconductor layer, the electrons accumulated in the organic semiconductor layer 19a are transferred to the body electrode 17a. Can be easily removed from the side.
  • stable TFT characteristics can be realized while suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • the material of the body electrode 17a is selected from the source electrode 14a and the drain electrode 14b in order to extract holes accumulated in the n-type organic semiconductor layer 19a by light irradiation. It is desirable to use a material having a large work function, such as Pt, Rh, Au, Cu, Ag, Ta, Al, W, Mo, MoW, MnO 2 , MnO 3 , Ni, Ti, Cr, etc.
  • a metal film having a laminated structure in which the layers are stacked and combined can be employed.
  • C60 fullerene (HOMO level: about 6.2 eV, LUMO level: about 4.5 eV) is adopted as the material of the n-type organic semiconductor layer 19a, and Al (work function :) is used as the material of the source electrode 14a and the drain electrode 14b.
  • Pt (work function: about 5.7 eV) can be adopted as the material of the body electrode 17a.
  • the work function (about 5.7 eV) of the body electrode 17a is close to the HOMO level (about 6.2 eV) of the organic semiconductor layer 19a, the holes accumulated in the organic semiconductor layer 19a are used as the body electrode. It can be easily extracted from the 17a side. As a result, in the organic thin film transistor 1B according to the present embodiment, stable TFT characteristics can be realized while suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • a thin oxide film layer of about several nm may be formed between the body electrode 17a and the organic semiconductor layer 19a.
  • FIGS. 27 (A), (B) show the first step of forming the interlayer protective layer and interlayer mask layer of the thin film transistor substrate shown in FIGS. 19 (A), (B). It is a figure which shows a 2nd process.
  • 28A and 28B are diagrams showing a process of forming the pixel electrode, source electrode terminal, and body electrode terminal of the thin film transistor substrate shown in FIGS. 19A and 19B.
  • the step of forming the interlayer protective layer 22 and the interlayer mask layer 23A, the pixel electrode 25b, the source electrode terminal 25a, and the body electrode In the step of forming the terminals, the thin film transistor substrate 2B including the organic thin film transistor 1B having the bottom gate-top contact structure can be manufactured by performing substantially the same process as the manufacturing method of the thin film transistor substrate according to the first embodiment. .
  • the body electrode 17a is formed of a material different from that of the source electrode 14a and the drain electrode 14b, thereby forming the source electrode 14a and the drain electrode 14b.
  • the work function and the work function of the body electrode 17a are different.
  • the source electrode 14a and the drain electrode 14b are formed after the organic semiconductor layer 19a is formed, so that the organic semiconductor film 19 is applied and baked.
  • the source electrode 14a and the drain electrode 14b can be prevented from being oxidized.
  • the contact resistance defect can be reduced, and at the same time, the options for the source electrode and the drain electrode can be expanded.
  • FIGS. 29A and 29B are a cross-sectional view and a body electrode extending direction when a thin film transistor substrate including the organic thin film transistor according to the fourth embodiment is divided along the direction in which the source electrode and the drain electrode are arranged. It is sectional drawing at the time of dividing along.
  • FIGS. 29A and 29B an organic thin film transistor 1C according to the present embodiment and a thin film transistor substrate 2C including the same will be described. Note that FIG. 29A illustrates a portion corresponding to FIG. 2A, and FIG. 29B illustrates a portion corresponding to FIG. 2B.
  • the organic thin film transistor 1C according to the present embodiment and the thin film transistor substrate 2C having the same are the organic thin film transistor 1B according to the third embodiment and the thin film transistor substrate 2B having the same. Is different in that the body electrode 17b has a work function different from that of the source electrode and the drain electrode by subjecting the body electrode 17b to a surface treatment, and the other configurations are substantially the same. .
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of the same metal material, and a self-assembled monolayer 93 is formed at the interface between the body electrode 17b and the organic semiconductor layer 19a.
  • a self-assembled monolayer 93 is formed at the interface between the body electrode 17b and the organic semiconductor layer 19a.
  • the source electrode 14a and the self-assembled monolayer 93 are formed so as to cover the surface of the body electrode 17b.
  • the work function of the drain electrode 14b and the work function of the body electrode 17b can be made different.
  • materials similar to those in the second embodiment can be employed as the material for the source electrode 14a, the drain electrode 14b, and the body electrode 17b, the material for the organic semiconductor layer 19a, and the material for the self-assembled monolayer.
  • the surface of the body electrode 17b is subjected to plasma treatment and UV treatment.
  • the work function of the body electrode 17b can be made different from that of the source electrode 14a and the drain electrode 14b.
  • the method of manufacturing the thin film transistor substrate 2C according to the present embodiment basically conforms to the method of manufacturing the thin film transistor substrate 2B according to the third embodiment, and has a surface treatment process, and thus the thin film transistor substrate according to the third embodiment. It is different from the manufacturing method of 2B.
  • the step of forming the base coat layer first, in the step of forming the base coat layer, the step of forming the gate electrode, the step of forming the gate insulating layer, and the step of forming the organic semiconductor layer
  • the base coat layer 11, the gate electrode 12, the gate insulating layer 13, and the organic semiconductor layer 19 a are formed on the substrate 10 by performing the same process as in the method for manufacturing the thin film transistor substrate according to the third embodiment.
  • FIGS. 30 (A) and 30 (B) are diagrams showing a process of forming the source electrode, the drain electrode, and the body electrode of the thin film transistor substrate shown in FIGS. 29 (A) and 29 (B).
  • a source electrode 14a, a drain electrode 14b, and a body electrode 17b patterned in a predetermined shape by a vacuum deposition method, a sputtering method, or the like are formed with a thickness of about 100 to 400 nm. To do.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are formed by the sputtering method, after forming the source / drain / body electrode film on the entire substrate 10 on which the organic semiconductor layer 19a is formed, the source / drain / body electrode film is formed. A photosensitive resist is applied on the drain / body electrode film. Thereafter, the photosensitive resist is patterned by photolithography (exposure / development). Subsequently, the source electrode 14a, the drain electrode 14b, and the body electrode 17b are patterned by wet etching or dry etching of the gate electrode film using the photosensitive resist as a mask.
  • the source electrode 14a and the drain electrode 14b that are in contact with the end of the upper surface of the organic semiconductor layer 19a, respectively, and the body electrode 17b whose tip is in contact with the upper surface of the organic semiconductor layer 19a are formed.
  • the process of patterning separately by evaporating the said metal film using a metal mask becomes unnecessary.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of a material having a high work function and a small hole injection barrier to the p-type organic semiconductor layer 19a.
  • the metal film can be used.
  • the material of the source electrode 14a, the drain electrode 14b, and the body electrode 17b is Au (work function: About 5.0 eV) can be employed.
  • the material of the source electrode 14a, the drain electrode 14b, and the body electrode 17b is Au (work function: About 5.0 eV) can be employed.
  • the material for the source electrode 14a, the drain electrode 14b, and the body electrode 17b is a material having a small work function and a small barrier for electron injection into the n-type organic semiconductor layer 19a. It is preferable to adopt metal films such as Na, Mg, Ca, Al, Ag, Cu, Au, W, Mo, MoW, Ni, Ti, and Cr, and a metal film having a laminated structure in which these are stacked and combined. can do.
  • the material of the source electrode 14a, the drain electrode 14b, and the body electrode 17b is Au (work function: About 5.0 eV) can be employed.
  • the electron injection barrier height is small (about 0.5 eV)
  • electrons can be easily injected into the organic semiconductor layer 19a from the source electrode 14a and the drain electrode 14b, and a large current flows into the organic thin film transistor 1C. Can flow.
  • FIGS. 31 (A) and 31 (B) are views showing a step of performing surface treatment on the body electrode shown in FIGS. 30 (A) and 30 (B).
  • a self-assembled monolayer 93 is formed so as to cover the surface.
  • the self-assembled monolayer 93 the same material as that in Embodiment 2 can be used.
  • the work function of the body electrode (Au) can be reduced from about 5.0 eV to about 4.3 eV.
  • the work function of the body electrode (Cu) can be reduced from 4.7 eV to about 4.0 eV.
  • the work function of the body electrode 17b can be reduced to a value close to the LUMO level (about 3.5 eV) of copper phthalocyanine which is the p-type organic semiconductor layer 19a, the work function of the body electrode 17b is introduced into the organic semiconductor layer 19a via the body electrode 17b. Accumulated electrons can be easily extracted. As a result, in the organic thin film transistor 1C according to the present embodiment, stable TFT characteristics can be realized by suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • the drain electrode 14b and the body electrode 17b HBT or FBT is applied to the surface of the body electrode 17b.
  • the work function of the body electrode (Au) can be increased from about 5.0 eV to about 5.2 eV.
  • the work function of the body electrode (Al) can be increased from 4.3 eV to 4.5 eV.
  • the work function of the body electrode 17b can be brought close to the HOMO level (about 6.2 eV) of C60 fullerene, which is the n-type organic semiconductor layer 19a, the work function is accumulated in the organic semiconductor layer 19a via the body electrode 17b. Holes can be easily extracted. As a result, in the organic thin film transistor 1C according to the present embodiment, stable TFT characteristics can be realized by suppressing a shift in TFT characteristics during light irradiation or light OFF.
  • the same method as the method of manufacturing the thin film transistor substrate 2 according to the first embodiment the same method as the method of manufacturing the thin film transistor substrate 2 according to the first embodiment.
  • the thin film transistor substrate 2C including the organic thin film transistor 1C having the bottom gate-top contact structure can be manufactured.
  • the surface is formed only on the surface of the body electrode 17b.
  • the work functions of the source electrode 14a and the drain electrode 14b are different from the work function of the body electrode 17a.
  • the body electrode 17b can be formed with the same material as the source electrode 14a and the drain electrode 14b, thereby reducing the number of steps and material cost, Manufacturing cost can be reduced.
  • 32A and 32B are cross-sectional views when the thin film transistor substrate including the organic thin film transistor according to the fifth embodiment is divided along the direction in which the source electrode and the drain electrode are arranged, and in the extending direction of the body electrode. It is sectional drawing at the time of dividing along.
  • FIGS. 32A and 32B an organic thin film transistor 1D according to the present embodiment and a thin film transistor substrate 2D including the same will be described.
  • 32A shows a portion corresponding to FIG. 2A
  • FIG. 32B shows a portion corresponding to FIG. 2B.
  • the organic thin film transistor 1D according to the present embodiment and the thin film transistor substrate 2D having the same are the organic thin film transistor 1 according to the first embodiment and the thin film transistor substrate 2 having the same. Is different from the bottom gate-bottom contact structure in that it is a top gate-bottom contact structure, and the other configurations are substantially the same.
  • the organic thin film transistor 1D includes a substrate 10, a base coat layer 11 formed so as to cover the main surface of the substrate 10, and a source disposed on the base coat layer 11 so as to be separated from each other.
  • the base coat layer 11 located between the electrode 14a and the drain electrode 14b, the body electrode 17a disposed on the base coat layer 11 separately from the source electrode 14a and the drain electrode 14b, and the source electrode 14a and the drain electrode 14b.
  • an organic semiconductor layer 19a in contact with at least a part of the upper surface of each of the source electrode 14a, the drain electrode 14b, and the body electrode 17a.
  • the organic thin film transistor 1D includes a base coat layer 11 so as to cover the first protective layer 20a and the mask layer 21A provided to overlap the organic semiconductor layer 19a, and the mask layer 21A, the source electrode 14a, the drain electrode 14b, and the body electrode 17a.
  • the second protective layer 30 provided above, the gate insulating layer 13 provided so as to cover the second protective layer 30, and the organic semiconductor layer 19a provided on the gate insulating layer 13 so as to face each other.
  • the source electrode 14a and the drain electrode 14b are provided so that at least a part thereof overlaps the gate electrode 12 with the gate insulating layer 13 interposed therebetween.
  • the source electrode 14a and the drain electrode 14b are parts for allowing a current to flow through the organic semiconductor layer 19a.
  • the body electrode 17a is provided so as not to overlap the gate electrode 12.
  • the body electrode 17a is a part for removing charges accumulated in the organic semiconductor layer 19a.
  • the body electrode 17a with a material different from that of the source electrode 14a and the drain electrode 14b, the work function of the source electrode 14a and the drain electrode 14b is different from the work function of the body electrode 17a.
  • the thin film transistor substrate 2D includes an organic thin film transistor 1D, an interlayer protective layer 22 provided so as to cover the organic thin film transistor 1D, and an interlayer mask layer 23A provided so as to cover the interlayer protective layer 22.
  • a source electrode terminal 25a connected to the source electrode 14a of the organic thin film transistor 1 through the contact hole 24a, a pixel electrode 25b connected to the drain electrode 14b of the organic thin film transistor 1 through the contact hole 24b, and a contact hole 24c.
  • a body electrode terminal 25c connected to the body electrode 17a of the organic thin film transistor 1 via
  • Contact holes 24a, 24b, and 24c are formed in the interlayer mask layer 23A, the interlayer protection layer 22, the gate insulating layer 13, and the second protection layer 30.
  • the contact hole 24a is provided so as to reach the source electrode 14a from the surface side of the interlayer mask layer 23A.
  • the contact hole 24b is provided so as to reach the drain electrode 14b from the surface side of the interlayer mask layer 23A.
  • the contact hole 24c is provided so as to reach the body electrode 17a from the surface side of the interlayer mask layer 23A.
  • the manufacturing method of the thin film transistor substrate 2D according to the present embodiment basically conforms to the manufacturing method of the thin film transistor substrate according to the first embodiment, and before the step of forming the gate insulating layer and the step of forming the gate electrode. , And a step of forming a source electrode and a drain electrode, a step of forming a body electrode, a step of forming an organic semiconductor layer, a protective layer and a mask layer, and a step of forming a second protective film.
  • the substrate 10 is subjected to the same processing as the method of manufacturing the thin film transistor substrate according to the first embodiment.
  • Base coat layer 11 is formed.
  • FIGS. 33 (A) and 33 (B) are diagrams showing a process of forming a source electrode and a drain electrode of the thin film transistor substrate shown in FIGS. 32 (A) and 32 (B).
  • a process substantially similar to the method for manufacturing the thin film transistor substrate according to Embodiment 1 is performed, so that the base coat layer 11 is formed.
  • a source electrode 14a and a drain electrode 14b that are spaced apart from each other are formed.
  • FIGS. 34A and 34B and FIGS. 35A and 35B show the first step and the second step of the step of forming the body electrode of the thin film transistor substrate shown in FIGS. 32A and 32B.
  • FIG. As shown in FIGS. 34A and 34B and FIGS. 35A and 35B, in the first and second steps of forming the body electrode, the thin film transistor substrate according to the first embodiment is manufactured.
  • a body electrode 17a separated from the source electrode 14a and the drain electrode 14b is formed on the base coat layer 11 by performing a process substantially similar to the method.
  • This step is different from Embodiment 1 in that a photosensitive resist 15 is applied on the main surface of the base coat layer 11 so as to cover the source electrode 14a and the drain electrode 14b.
  • an adhesion layer such as Ti or Cr may be formed between the base coat layer 11 and the source electrode 14a and drain electrode 14b.
  • FIGS. 36 (A), (B) and FIGS. 37 (A), (B) are steps for forming the organic semiconductor layer, the first protective layer, and the mask layer of the thin film transistor substrate shown in FIGS. 32 (A), (B). It is a figure which shows the 1st process and 2nd process.
  • the organic semiconductor in the first embodiment is used in the step of forming the organic semiconductor layer, the first protective layer, and the mask layer.
  • the base coat layer 11 located between the source electrode 14a and the drain electrode 14b is covered by performing substantially the same process as the step of forming the layer, the protective layer, and the mask layer, and the source electrode 14a and the drain electrode 14b are covered.
  • an organic semiconductor layer 19a in contact with at least a part of the upper surface of each of the body electrodes 17a, a first protective layer 20a and a mask layer 21A formed so as to overlap the organic semiconductor layer 19a are formed.
  • FIGS. 38 (A) and 38 (B) are diagrams showing a process of forming the second protective layer and the gate insulating layer of the thin film transistor substrate shown in FIGS. 32 (A) and 32 (B).
  • FIGS. 38A and 38B in the step of forming the second protective layer 30 and the gate insulating layer 13, first, the organic semiconductor layer 19a, the first protective layer 20a, and the mask layer 21A are formed.
  • a second protective layer 30 made of an inorganic insulating film, an organic insulating film, or a combination film of these is formed on the entire formed substrate by using a spin coating method, a slit coating method, an ink jet method, a printing method, or the like. To do.
  • a nitride film, an oxide film, a nitrided oxide film or the like can be adopted as the inorganic insulating film, and a CYTOP manufactured by Parylene, Asahi Glass Co., Ltd. can be used as the organic insulating film. (Registered trademark) or the like can be adopted. Note that the step of forming the second protective layer 30 may be omitted.
  • the gate insulating layer 13 is formed with a thickness of about 200 nm to 1000 nm by applying an organic insulating material such as polyvinylphenol (PVP) or polystyrene (PS) to the entire substrate and then baking it.
  • PVP polyvinylphenol
  • PS polystyrene
  • FIGS. 39 (A) and 39 (B) are diagrams showing a process of forming the gate electrode of the thin film transistor substrate shown in FIGS. 32 (A) and 32 (B).
  • a process substantially similar to the method for manufacturing the thin film transistor substrate 2 according to the first embodiment is performed, so that the gate electrode 13 is formed.
  • the gate electrode 12 is formed to face the organic semiconductor layer 19a. Thereby, the organic thin film transistor 1D according to the present embodiment is manufactured.
  • FIGS. 40 (A), (B) and FIGS. 41 (A), (B) show the first step of forming the interlayer protective layer and the interlayer mask layer of the thin film transistor substrate shown in FIGS. 32 (A), (B). It is a figure which shows a 2nd process.
  • FIGS. 40A and 40B in the first step of forming the interlayer protective layer 22 and the interlayer mask layer 23A, the same process as the method for manufacturing the thin film transistor according to the first embodiment is performed.
  • the interlayer protection layer 22 is formed on the gate insulating layer 13 so as to cover the gate electrode 12, and the organic insulating film 23 for forming the interlayer mask layer 23 ⁇ / b> A is formed so as to cover the interlayer protection layer 22.
  • the organic insulating film 23 for example, a negative type organic insulating film can be adopted. By exposing and developing the organic insulating film 23 other than the region where the contact holes 24a, 24b, and 24c are formed, the contact is obtained. An interlayer mask layer 23A is formed in a region other than the region where the holes 24a, 24b, and 24c are to be formed.
  • FIGS. 42A and 42B are diagrams showing a process of forming a pixel electrode, a source electrode terminal, and a body electrode terminal of the thin film transistor substrate shown in FIGS. 32A and 32B.
  • the pixel electrode 25b, the source electrode terminal 25a, and the body electrode terminal 25c are formed by performing substantially the same process as the manufacturing method of the thin film transistor substrate 2 according to the first embodiment. Form.
  • a thin film transistor substrate including the organic thin film transistor 1D having a top gate-bottom contact structure can be manufactured.
  • the same material as that of the first embodiment is adopted as the material of the source electrode 14a and the drain electrode 14b, the material of the body electrode 17a, and the material of the organic semiconductor layer 19a. Can do.
  • the hole injection barrier height can be reduced by making the work function of the source electrode 14a close to the HOMO level of the organic semiconductor layer 19a. For this reason, holes can be easily injected into the organic semiconductor layer 19a from the source electrode 14a and the drain electrode 14b, and a large current can flow in the organic thin film transistor 1D.
  • the work function of the body electrode 17a is lower than the LUMO level of the organic semiconductor layer 19a, electrons accumulated in the organic semiconductor layer 19a can be easily extracted through the body electrode 17a.
  • the electron injection barrier can be almost eliminated by bringing the work function of the source electrode 14a close to the LUMO level of the organic semiconductor layer 19a. For this reason, electrons can be easily injected from the source electrode 14a into the organic semiconductor layer 19a, and a large current can flow in the organic thin film transistor 1D.
  • the work function of the body electrode 17a is close to the HOMO level of the organic semiconductor layer 19a, holes accumulated in the organic semiconductor layer 19a can be easily extracted through the body electrode 17a.
  • the light is irradiated or light is turned off regardless of whether the organic semiconductor layer 19a is p-type or n-type.
  • Stable TFT characteristics can be realized by suppressing a shift in TFT characteristics at the time.
  • the organic thin film transistor 1D according to the present embodiment and the thin film transistor substrate 2D having the same can obtain substantially the same effects as the organic thin film transistor 1 according to the first embodiment and the thin film transistor substrate 2 having the same.
  • FIGS. 43A and 43B are a cross-sectional view and a body electrode extending direction when a thin film transistor substrate including the organic thin film transistor according to the sixth embodiment is divided along the direction in which the source electrode and the drain electrode are arranged. It is sectional drawing at the time of dividing along.
  • FIGS. 43A and 43B an organic thin film transistor 1E according to the present embodiment and a thin film transistor substrate 2E including the same will be described.
  • 43A shows a portion corresponding to FIG. 2A
  • FIG. 43B shows a portion corresponding to FIG. 2B.
  • the organic thin film transistor 1E according to the present embodiment and the thin film transistor substrate 2E having the same are the organic thin film transistor 1D according to the fifth embodiment and the thin film transistor substrate 2D having the same. Is different in that a body electrode 17b having a work function different from that of the source electrode 14a and the drain electrode 14b is provided by subjecting the body electrode 17b to a surface treatment, and the other configurations are substantially the same. It is.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of the same metal material, and a self-assembled monolayer 93 is formed at the interface between the body electrode 17b and the organic semiconductor layer 19a.
  • a self-assembled monolayer 93 is formed at the interface between the body electrode 17b and the organic semiconductor layer 19a.
  • the source electrode 14a and the self-assembled monolayer 93 are formed so as to cover the surface of the body electrode 17b.
  • the work function of the drain electrode 14b and the work function of the body electrode 17b can be made different.
  • the same materials as those in Embodiment 2 can be employed. .
  • the method for manufacturing the thin film transistor substrate 2E according to the present embodiment is basically in accordance with the method for manufacturing the thin film transistor substrate 2D according to the fifth embodiment, and has a surface treatment step, and thus the thin film transistor substrate according to the fifth embodiment. It is different from the 2D manufacturing method.
  • the same process as that of the method of manufacturing the thin film transistor substrate 2D according to the fifth embodiment is performed.
  • the base coat layer 11 is formed.
  • FIGS. 44 (A) and 44 (B) are diagrams showing a process of forming a source electrode, a drain electrode, and a body electrode of the thin film transistor substrate shown in FIGS. 43 (A) and 43 (B).
  • a source electrode 14a, a drain electrode 14b, and a body electrode 17b patterned in a predetermined shape by a vacuum deposition method, a sputtering method, or the like are formed with a thickness of about 100 to 400 nm.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of the same material.
  • FIGS. 45 (A) and 45 (B) are diagrams showing a step of performing a surface treatment on the body electrode shown in FIGS. 43 (A) and 43 (B).
  • the body electrode 17b is subjected to substantially the same treatment as that of the thin film transistor substrate 2A according to the second embodiment.
  • a self-assembled monolayer 93 is formed so as to cover the surface. Thereby, the work function of the body electrode 17b can be changed.
  • the photosensitive resist 16 is applied on the base coat layer 11 on which the source electrode 14a, the drain electrode 14b, and the body electrode 17b are formed so that only the surface of the body electrode 17b is exposed.
  • the step of forming the organic semiconductor layer, the first protective layer and the mask layer, the step of forming the second protective layer and the gate insulating layer, the step of forming the gate electrode, the interlayer protective layer and the interlayer mask layer are formed.
  • the thin film transistor substrate according to the present embodiment is performed by performing the same process as the manufacturing method of the thin film transistor substrate 2D according to the fifth embodiment. 2E is formed.
  • the thin film transistor substrate 2E including the organic thin film transistor 1E having a top gate-bottom contact structure can be manufactured.
  • the surface is formed only on the surface of the body electrode 17b.
  • the work functions of the source electrode 14a and the drain electrode 14b are different from the work function of the body electrode 17a.
  • the same materials as those in the second embodiment are employed. be able to.
  • the hole injection barrier height can be reduced by bringing the work function of the source electrode 14a close to the HOMO level of the organic semiconductor layer 19a. For this reason, holes can be easily injected into the organic semiconductor layer 19a from the source electrode 14a and the drain electrode 14b, and a large current can flow in the organic thin film transistor 1E.
  • the self-assembled monomolecular film 93 for example, MBT is applied on the surface of the body electrode 17b, so that the work function of the body electrode can be reduced to approach the LUMO level of the organic semiconductor layer 19a. Thereby, the electrons accumulated in the organic semiconductor layer 19a can be easily extracted through the body electrode 17a.
  • the electron injection barrier can be almost eliminated by bringing the work function of the source electrode 14a close to the LUMO level of the organic semiconductor layer 19a. For this reason, electrons can be easily injected from the source electrode 14a into the organic semiconductor layer 19a, and a large current can flow in the organic thin film transistor 1E.
  • the work function of the body electrode can be increased to approach the HOMO level of the organic semiconductor layer 19a.
  • the holes accumulated in the organic semiconductor layer 19a can be easily extracted through the body electrode 17a.
  • the organic thin film transistor 1E according to the present embodiment and the thin film transistor substrate 2E having the organic thin film transistor 1E even when the organic semiconductor layer 19a is p-type or n-type, the light irradiation or light OFF is performed. Stable TFT characteristics can be realized by suppressing a shift in TFT characteristics at the time.
  • the organic thin film transistor 1E according to the present embodiment and the thin film transistor substrate 2E having the same can obtain substantially the same effects as the organic thin film transistor 1D according to the fifth embodiment and the thin film transistor substrate 2D having the same.
  • the body electrode 17b can be formed using the same material as the source electrode 14a and the drain electrode 14b. Cost can be reduced.
  • FIGS. 46A and 46B are a cross-sectional view when the thin film transistor substrate including the organic thin film transistor according to the seventh embodiment is divided along the direction in which the source electrode and the drain electrode are arranged, and in the extending direction of the body electrode. It is sectional drawing at the time of dividing along.
  • FIGS. 46A and 46B an organic thin film transistor 1F according to the present embodiment and a thin film transistor substrate 2F including the same will be described.
  • 46A shows a portion corresponding to FIG. 2A
  • FIG. 46B shows a portion corresponding to FIG. 2B.
  • the organic thin film transistor 1F according to the present embodiment and the thin film transistor substrate 2F having the same are the organic thin film transistor 1D according to the fifth embodiment and the thin film transistor substrate 2D having the same.
  • the source electrode 14a and the drain electrode 14b are different in that the first protective layer 20a and the mask layer 21A are not formed. Other configurations are almost the same.
  • the organic thin film transistor 1F includes a substrate 10, a base coat layer 11 formed so as to cover the main surface of the substrate 10, and an organic semiconductor layer 19a formed on the base coat layer 11.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17a provided on the base coat layer 11 so as to be in contact with the end of the upper surface of the organic semiconductor layer 19a, and the organic semiconductor layer 19a, the source electrode 14a, the drain electrode 14b, and the body.
  • a gate insulating layer 13 provided on the base coat layer 11 so as to cover the electrode 17a and a gate electrode 12 provided so as to face the organic semiconductor layer 19a with the gate insulating layer 13 interposed therebetween are provided.
  • the source electrode 14a and the drain electrode 14b are disposed so as to be separated from each other, and are provided so that at least a part thereof overlaps the gate electrode 12 with the gate insulating layer 13 interposed therebetween.
  • the source electrode 14a and the drain electrode 14b are parts for allowing a current to flow through the organic semiconductor layer 19a.
  • the body electrode 17a is disposed separately from the source electrode 14a and the drain electrode 14b, and is provided so as not to overlap the gate electrode 12.
  • the body electrode 17a is a part for removing charges accumulated in the organic semiconductor layer 19a.
  • the body electrode 17a with a material different from that of the source electrode 14a and the drain electrode 14b, the work function of the source electrode 14a and the drain electrode 14b is different from the work function of the body electrode 17a.
  • the manufacturing method of the thin film transistor substrate 2F according to the present embodiment basically conforms to the manufacturing method of the thin film transistor substrate 2D according to the fifth embodiment, and is partially applied to the manufacturing method of the thin film transistor substrate 2B according to the third embodiment.
  • the manufacturing method of the thin film transistor substrate 2F according to the present embodiment includes a step of forming the organic semiconductor layer 19a before the step of forming the source electrode 14a and the drain electrode 14b, and a protective layer and a mask on the organic semiconductor layer 19a.
  • the method is different from the method of manufacturing the thin film transistor substrate 2D according to the fifth embodiment in that the layer forming step is not provided.
  • the base coat is applied to the substrate 10 by performing the same process as the method of manufacturing the thin film transistor substrate according to the fifth embodiment in the step of forming the base coat layer.
  • Layer 11 is formed.
  • FIGS. 47 (A), (B) and FIGS. 48 (A), (B) show the first step and the second step in the step of forming the organic semiconductor layer of the thin film transistor substrate shown in FIGS. 46 (A), (B).
  • FIG. 47 (A), (B) and FIGS. 48 (A), (B) substantially the same processing as the first step and the second step of the step of forming the organic semiconductor layer according to the third embodiment.
  • an organic semiconductor layer 19 a patterned in an island shape is formed on the base coat layer 11.
  • 49A, 49B, 50A, and 50B show the first step and the first step of forming the source electrode and the drain electrode of the thin film transistor substrate shown in FIGS. 46A and 46B. It is a figure which shows 2 processes. As shown in FIGS. 49A and 49B and FIGS. 50A and 50B, substantially the same as the first step and the second step in the step of forming the source electrode and the drain electrode according to the third embodiment. By performing this process, the source electrode 14a and the drain electrode 14b are formed on the base coat layer 11 so as to be separated from each other and in contact with the end portion of the upper surface of the organic semiconductor layer 19a.
  • FIGS. 51A and 51B and FIGS. 52A and 52B show the first step and the second step of forming the body electrode of the thin film transistor substrate shown in FIGS. 46A and 46B.
  • FIG. As shown in FIGS. 51 (A), (B) and FIGS. 52 (A), (B), substantially the same processing as the first step and the second step of the step of forming the body electrode according to the third embodiment is performed.
  • the body electrode 17a is formed on the base coat layer 11 so as to be separated from the source electrode 14a and the drain electrode 14b and so that a part of the tip is in contact with the upper surface of the organic semiconductor layer 19a.
  • FIGS. 53 (A) and 53 (B) are views showing a process of forming a gate insulating layer of the thin film transistor substrate shown in FIGS. 46 (A) and 46 (B).
  • an organic semiconductor layer 19a, a source electrode 14a, a drain electrode 14b, and a process similar to those in the step of forming the gate insulating layer according to the fifth embodiment are performed.
  • Gate insulating layer 13 is formed on base coat layer 11 so as to cover body electrode 17a.
  • FIGS. 54 (A) and 54 (B) are views showing a process of forming the gate electrode of the thin film transistor substrate shown in FIGS. 46 (A) and 46 (B).
  • the organic semiconductor layer 19a is opposed to the gate insulating layer 13 by performing almost the same process as the step of forming the gate electrode according to the fifth embodiment.
  • the gate electrode 12 is formed on the gate insulating layer 13.
  • the organic thin film transistor 1F according to the present embodiment is formed.
  • FIGS. 55A and 55B and FIGS. 56A and 56B show the first step of forming the interlayer protective layer and the interlayer mask layer of the thin film transistor substrate shown in FIGS. 46A and 46B. It is a figure which shows a 2nd process.
  • FIGS. 57A and 57B are diagrams showing a process of forming a pixel electrode, a source electrode terminal, and a body electrode terminal of the thin film transistor substrate shown in FIG. As shown in FIGS. 55A and 55B to FIGS.
  • the step of forming the interlayer protective layer and the interlayer mask layer according to the fifth embodiment, the pixel electrode, the source electrode terminal, and the body By performing substantially the same process as the step of forming the electrode terminals, the interlayer protective layer 22, the interlayer mask layer 23A, the pixel electrode 25b, the source electrode terminal 25a, and the body electrode terminal 25c are formed.
  • the thin film transistor substrate 2F including the organic thin film transistor 1F having a top gate-top contact structure can be manufactured.
  • the body electrode 17a is formed of a material different from that of the source electrode 14a and the drain electrode 14b, thereby forming the source electrode 14a and the drain electrode 14b.
  • the work function and the work function of the body electrode 17a are different.
  • the material similar to Embodiment 3 can be employ
  • the source electrode 14a and the drain electrode 14b are formed after the organic semiconductor layer 19a is formed. This can prevent the source electrode 14a and the drain electrode 14b from being oxidized when the organic semiconductor film 19 is applied and baked. As a result, in the method for manufacturing the thin film transistor substrate according to the present embodiment, contact resistance defects can be reduced, and at the same time, options for the source electrode and the drain electrode can be expanded.
  • 58A and 58B are a cross-sectional view and a body electrode extending direction when a thin film transistor substrate including the organic thin film transistor according to the eighth embodiment is divided along the direction in which the source electrode and the drain electrode are arranged. It is sectional drawing at the time of dividing along.
  • FIGS. 58A and 58B an organic thin film transistor 1G according to the present embodiment and a thin film transistor substrate 2G including the same will be described.
  • 58A shows a portion corresponding to FIG. 2A
  • FIG. 58B shows a portion corresponding to FIG. 2B.
  • the organic thin film transistor 1G according to the present embodiment and the thin film transistor substrate 2G having the same are the organic thin film transistor 1F according to the seventh embodiment and the thin film transistor substrate 2F having the same.
  • the body electrode 17b is subjected to a surface treatment, the body electrode 17b has a work function different from that of the source electrode 14a and the drain electrode 14b. It is the same.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of the same metal material, and a self-assembled monolayer 93 is formed at the interface between the body electrode 17b and the organic semiconductor layer 19a.
  • the source electrode 14a and the drain are formed by forming the self-assembled monolayer so as to cover the surface of the body electrode 17b.
  • the work function of the electrode 14b and the work function of the body electrode 17b can be made different.
  • the same materials as those in Embodiment 4 can be employed. .
  • the manufacturing method of the thin film transistor substrate 2G according to the present embodiment basically conforms to the manufacturing method of the thin film transistor substrate 2F according to the seventh embodiment, and is partially applied to the manufacturing method of the thin film transistor substrate 2C according to the fourth embodiment. It conforms.
  • the manufacturing method of the thin film transistor substrate 2G according to the present embodiment is different from the manufacturing method of the thin film transistor substrate 2F according to the seventh embodiment in that it includes a surface treatment process.
  • the manufacturing method of the thin film transistor substrate 2G according to the present embodiment first, in the step of forming the base coat layer and the step of forming the organic semiconductor layer, substantially the same as the manufacturing method of the thin film transistor substrate 2F according to the seventh embodiment. By performing the treatment, the base coat layer 11 and the organic semiconductor layer 19a are formed on the substrate 10.
  • FIGS. 59A and 59B are diagrams showing a process of forming a source electrode, a drain electrode, and a body electrode of the thin film transistor substrate shown in FIGS. 58A and 58B.
  • a source electrode 14a, a drain electrode 14b, and a body electrode 17b that are patterned into a predetermined shape by a vacuum deposition method, a sputtering method, or the like are formed with a thickness of about 100 to 400 nm.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of the same material.
  • 60 (A) and 60 (B) are diagrams showing a process of performing a surface treatment on the body electrode shown in FIGS. 59 (A) and 59 (B).
  • the body electrode 17b is subjected to substantially the same treatment as that of the thin film transistor substrate 2C according to the fourth embodiment.
  • a self-assembled monolayer 93 is formed so as to cover the surface. Thereby, the work function of the body electrode 17b can be changed.
  • the photosensitive resist 29 is applied on the base coat layer 11 so that the surface of the body electrode 17b is exposed.
  • the step of forming the organic semiconductor layer, the first protective layer and the mask layer, the step of forming the second protective layer and the gate insulating layer, the step of forming the gate electrode, the interlayer protective layer and the interlayer mask layer are formed.
  • the thin film transistor substrate according to the present embodiment is performed by performing the same process as the manufacturing method of the thin film transistor substrate 2F according to the seventh embodiment. 2G is formed.
  • the thin film transistor substrate 2G including the organic thin film transistor 1G having a top gate-top contact structure can be manufactured.
  • the surface is formed only on the surface of the body electrode 17b.
  • the work functions of the source electrode 14a and the drain electrode 14b are different from the work function of the body electrode 17a.
  • the same materials as those in the fourth embodiment are employed. be able to.
  • the hole injection barrier height can be reduced by bringing the work function of the source electrode 14a close to the HOMO level of the organic semiconductor layer 19a. For this reason, holes can be easily injected from the source electrode 14a and the drain electrode 14b into the organic semiconductor layer 19a, and a large current can flow in the organic thin film transistor 1G.
  • the self-assembled monomolecular film 93 for example, MBT is applied on the surface of the body electrode 17b, so that the work function of the body electrode can be reduced to approach the LUMO level of the organic semiconductor layer 19a. Thereby, the electrons accumulated in the organic semiconductor layer 19a can be easily extracted through the body electrode 17a.
  • the electron injection barrier can be almost eliminated by bringing the work function of the source electrode 14a close to the LUMO level of the organic semiconductor layer 19a. For this reason, electrons can be easily injected from the source electrode 14a into the organic semiconductor layer 19a, and a large current can flow in the organic thin film transistor 1G.
  • the self-assembled monomolecular film 93 for example, HBT or FBT is applied to the surface of the body electrode 17b, so that the work function of the body electrode can be increased to approach the HOMO level of the organic semiconductor layer 19a. Thereby, the holes accumulated in the organic semiconductor layer 19a can be easily extracted through the body electrode 17a.
  • the organic thin film transistor 1G according to the present embodiment and the thin film transistor substrate having the organic thin film transistor 1G even when the organic semiconductor layer 19a is p-type or n-type, the light is irradiated or the light is turned off. Stable TFT characteristics can be realized by suppressing the TFT characteristic shift.
  • the organic thin film transistor 1G according to the present embodiment and the thin film transistor substrate 2G having the same can obtain substantially the same effects as the organic thin film transistor 1F according to the seventh embodiment and the thin film transistor substrate 2F having the same.
  • the body electrode 17b can be formed using the same material as the source electrode 14a and the drain electrode 14b. Cost can be reduced.
  • FIG. 61 is a plan view of an organic thin film transistor according to the ninth embodiment.
  • 62 is a diagram showing energy levels of the organic thin film transistor shown in FIG.
  • An organic thin film transistor 1H according to the present embodiment will be described with reference to FIGS.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b are made of the same material.
  • the source electrode 14a, the drain electrode 14b, and the body electrode 17b have the same work function, and the other configurations are substantially the same.
  • the body electrode 17b is applied to the source electrode 14a.
  • the charge accumulated in the organic semiconductor layer 19a can be extracted.
  • the organic semiconductor layer 19a is p-type and electrons are accumulated in the organic semiconductor layer 19a, a positive high voltage is applied to the body electrode 17b, so that electrons are extracted from the organic semiconductor layer 19a. Can be pulled out.
  • FIG. 64 is a diagram showing a first example of an equivalent circuit diagram of the liquid crystal display device shown in FIG. 63.
  • a liquid crystal display device 100 according to the present embodiment will be described with reference to FIGS.
  • the case where the organic thin film transistor 1 according to the first embodiment is used as a switching element in the liquid crystal display device 100 will be described as an example, but instead of the organic thin film transistor 1 according to the first embodiment.
  • Any of the organic thin film transistors according to the second to ninth embodiments may be used as a switching element.
  • the liquid crystal display device 100 includes a liquid crystal display panel 90 and a backlight unit 45 that irradiates light toward the liquid crystal display panel 90.
  • the liquid crystal display panel 90 is provided between the thin film transistor substrate 2 disposed on the backlight unit 45 side, the counter substrate 42 disposed to face the thin film transistor substrate 2, and the thin film transistor substrate 2 and the counter substrate 42. And a liquid crystal layer 43.
  • the liquid crystal layer 43 is sealed between the thin film transistor substrate 2 and the counter substrate 42 by an annular sealing material (not shown) that bonds the thin film transistor substrate 2 and the counter substrate 42 to each other.
  • the liquid crystal layer 43 is made of a nematic liquid crystal material having electro-optical characteristics.
  • the counter substrate 42 includes a transparent substrate 40 such as a glass substrate, a color filter layer 41 formed on the main surface disposed on the liquid crystal layer 43 side, and a common electrode (not shown) formed on the color filter layer 41. Including. An alignment film for aligning the liquid crystal constituting the liquid crystal layer 43 is provided on the common electrode. An alignment film (not shown) is also provided on the thin film transistor substrate 2 so as to cover the entire surface on the pixel electrode 25b side.
  • the backlight unit 45 includes a light source 44 that emits light toward the liquid crystal display panel 90.
  • a light source 44 an LED, a cold cathode tube, or the like can be employed.
  • the thin film transistor substrate 2 has a plurality of scanning signal lines GL provided so as to extend in parallel to each other, and extend in parallel to each other in a direction intersecting the scanning signal lines GL.
  • a plurality of video signal lines DL provided and a plurality of constant potential lines VL provided so as to extend in parallel with the video signal lines DL are disposed between the adjacent video signal lines DL.
  • auxiliary capacitance lines are arranged between the adjacent scanning signal lines GL so as to extend in parallel with the scanning signal lines GL.
  • the organic thin film transistor 1 is provided in the vicinity of a portion where the plurality of scanning signal lines GL and the plurality of video signal lines DL intersect, and the organic thin film transistor 1 is provided for each pixel.
  • the gate electrode 12 (gate electrode G) of the organic thin film transistor 1 is connected to the scanning signal wiring GL.
  • the source electrode 14a (source electrode S) of the organic thin film transistor 1 is connected to the video signal wiring DL.
  • the drain electrode 14b (drain electrode D) of the organic thin film transistor 1 is connected to the pixel electrode 25b and the auxiliary capacitance electrode.
  • the body electrode 17a (body electrode BD) of the organic thin film transistor 1 is connected to the constant potential wiring VL.
  • the liquid crystal display device 100 includes a vertical operation circuit 50, a horizontal drive circuit 51, and a constant potential power circuit 52.
  • the vertical operation circuit 50 is connected to the scanning signal wiring GL via a gate terminal (not shown) provided at the end of the scanning signal wiring GL.
  • the horizontal drive circuit 51 is connected to the video signal line DL via a source electrode terminal 25a provided at the end of the video signal line DL.
  • the constant potential power circuit 52 is connected to the constant potential wiring VL via a body electrode terminal 25c provided at the end of the constant potential wiring VL.
  • the vertical operation circuit 50, the horizontal drive circuit 51, and the constant potential power supply circuit 52 function as drive circuits that drive a plurality of pixels in units of pixels.
  • the liquid crystal display device in each pixel, when the scanning signal is sent from the vertical operation circuit 50 to the gate electrode G via the scanning signal wiring GL, and the organic thin film transistor 1 is turned on, the image from the horizontal driving circuit 51 is displayed. A signal is sent to the source electrode S through the video signal wiring DL, and a predetermined charge is written into the pixel electrode 25b through the organic semiconductor layer 19a and the drain electrode D.
  • the light transmittance of the liquid crystal layer 43 is adjusted by changing the alignment state of the liquid crystal layer 43 according to the magnitude of the voltage applied to the liquid crystal layer 43 in each pixel. As a result, an image is displayed on the liquid crystal display device 100.
  • the liquid crystal display device 100 can realize a stable TFT characteristic by suppressing a shift of a threshold voltage during light irradiation or light OFF. As a result, the liquid crystal display device 100 can obtain a stable display quality that is not easily affected by light such as external light and backlight light.
  • the scanning signal wiring GL is preferably formed of the same material as the gate electrode in the step of forming the gate electrode of the organic thin film transistor 1.
  • the video signal line DL is preferably formed of the same material as the source electrode and the drain electrode in the step of forming the source electrode and the drain electrode of the organic thin film transistor 1.
  • the constant potential wiring VL is preferably formed of the same material as the body electrode in the step of forming the body electrode.
  • the source electrode, the drain electrode, and the body electrode are formed of the same material in the step of forming the source electrode, the drain electrode, and the body electrode.
  • FIG. 65 is a diagram showing a second example of an equivalent circuit diagram of the liquid crystal display device shown in FIG. 63.
  • a liquid crystal display device 100A according to the present embodiment will be described with reference to FIG.
  • the liquid crystal display device 100A according to the present embodiment does not include the constant potential power supply circuit and the constant potential wiring, and the body electrode 17a is connected to the auxiliary capacitance wiring. In other respects, the configuration is substantially the same.
  • the body electrode 17a is configured to have the same potential as the auxiliary capacitance electrode and the common electrode, the charges (electrons or holes) accumulated in the organic semiconductor layer 19a by the light irradiation pass through the body electrode 17a. Sucked out of the auxiliary capacity wiring. Thereby, even in the liquid crystal display device 100 according to the present embodiment, substantially the same effect as the liquid crystal display device 100 according to the tenth embodiment can be obtained.
  • the body electrode 17a may be connected to the common electrode of the counter substrate 42.
  • FIG. 12 is a schematic cross-sectional view showing a first embodiment of an organic EL display device including the thin film transistor substrate shown in FIG.
  • FIG. 67 is a diagram showing a first example of an equivalent circuit diagram of the organic EL display device shown in FIG.
  • An organic EL display device 200 according to the present embodiment will be described with reference to FIGS. 66 and 67.
  • FIG. In the present embodiment the case where the organic thin film transistor 1 according to the first embodiment is used as an organic thin film transistor for driving EL in the organic EL display device 200 will be described as an example.
  • any one of the organic thin film transistors according to the second to ninth embodiments may be used as an organic thin film transistor for driving an EL.
  • a partition wall layer 31 provided on the thin film transistor substrate 2 an organic EL layer 32 provided on the pixel electrode 25b, a counter electrode 33 corresponding to a cathode electrode provided on the organic EL layer 32, and a counter electrode 33
  • a passivation layer 34 is provided so as to cover it, and a counter substrate 60 is disposed on the passivation layer 34.
  • the pixel electrode 25b corresponding to the anode electrode, the organic EL layer 32, and the counter electrode 33 corresponding to the cathode electrode constitute an organic light emitting diode OLED.
  • a transparent conductive film such as IZO, ITO, ZnO, or SnO can be used.
  • a reflective electrode such as Al, Al alloy, Ag or Ag alloy is used, or a transparent conductive film such as IZO or ITO is used as an upper layer, and Al, Al alloy or Ag is used as a lower layer. It is possible to use a laminated structure electrode in which reflective electrodes such as Ag alloy, Mo, and Cr are combined.
  • the organic EL layer 32 is configured by stacking a hole transport layer (HTL), an EL light emitting layer (EM), and an electron transport layer (ETL) in this order.
  • HTL hole transport layer
  • EM EL light emitting layer
  • ETL electron transport layer
  • TPD triphenyldiamine
  • the EL light emitting layer is preferably configured to be capable of color display by a red light emitting layer, a blue light emitting layer, and a green light emitting layer.
  • a red light emitting layer for example, tris (8-hydroxyquinoline) aluminum (Alq3) blended with DCJBT and rubrene can be employed.
  • the blue light emitting layer for example, DPVBi doped with BCzVBi can be employed.
  • the green light emitting layer for example, Alq3 doped with coumarin 540 can be employed.
  • a reflective electrode such as Al, Al alloy, Ag, or Ag alloy can be employed.
  • a transparent conductive film such as IZO, ITO, ZnO, SnO or a thin metal film such as Au, Ag, Mg, Mg—Ag is used (as a transparent counter electrode).
  • the passivation layer 34 is formed to prevent intrusion of moisture, oxygen, and the like.
  • an inorganic film such as SiN, SiO 2 , Al 2 O 3 , an organic film such as a resin, and a laminated film thereof are used. A combination of these can be used.
  • the counter substrate 60 a glass substrate or a plastic substrate such as PEN, PES, or PET can be employed.
  • the counter substrate 60 is bonded to the thin film transistor substrate on which the organic EL layer 32, the counter electrode 33, and the passivation layer 34 are formed with an adhesive or the like.
  • the thin film transistor substrate 2 has a plurality of scanning signal lines GL provided so as to extend in parallel to each other, and extend in parallel to each other in a direction intersecting the scanning signal lines GL.
  • a plurality of video signal lines DL provided and a plurality of anode current supply lines An provided between the adjacent video signal lines DL so as to extend in parallel to the video signal lines DL are provided. ing.
  • the anode current supply line An and the video signal line DL positioned away from the anode current supply line An are provided.
  • a region partitioned by is equivalent to a pixel.
  • an organic thin film transistor Ts for switching a charge storage capacitor Cs, an organic thin film transistor Td for driving an EL (organic thin film transistor 1), and an organic light emitting diode OLED are formed.
  • the gate electrode G of the organic thin film transistor Ts is connected to the scanning signal wiring GL.
  • the source electrode S of the organic thin film transistor Ts is connected to the video signal wiring.
  • the drain electrode D of the organic thin film transistor Ts is connected to one end side of the charge storage capacitor Cs and the gate electrode 12 of the organic thin film transistor Td for driving EL.
  • the source electrode 14a and the body electrode 17a of the organic thin film transistor Td are connected to the anode current supply wiring An.
  • the drain electrode 14b of the organic thin film transistor Td is connected to the anode electrode (pixel electrode 25b) of the organic light emitting diode OLED.
  • the other end side of the charge storage capacitor Cs is connected to the anode current supply wiring An.
  • the organic EL display device 200 includes a vertical operation circuit 50, a horizontal drive circuit 51, and an anode power supply circuit 53.
  • the vertical operation circuit 50 is connected to the scanning signal wiring GL via a gate terminal (not shown) provided at the end of the scanning signal wiring GL.
  • the horizontal drive circuit 51 is connected to the video signal line DL via a source electrode terminal 25a provided at the end of the video signal line DL.
  • the anode power supply circuit 53 is connected to the anode current supply wiring An via a terminal portion provided at the end of the anode current supply wiring An.
  • the vertical operation circuit 50, the horizontal drive circuit 51, and the anode power supply circuit 53 function as a drive circuit that drives a plurality of pixels in units of pixels.
  • each pixel when the scanning signal is sent from the vertical operation circuit 50 to the gate electrode G of the switching organic thin film transistor Ts via the scanning signal wiring GL, the horizontal driving circuit 51 is turned on.
  • the video signal is supplied to the source electrode S of the organic thin film transistor Ts through the video signal wiring DL.
  • the signal supplied to the source electrode S is held in the charge storage capacitor Cs.
  • the holding voltage of the charge storage capacitor Cs is a voltage between the gate electrode 12 and the source electrode 14a of the EL driving organic thin film transistor Td.
  • a constant current corresponding to the voltage between the gate electrode 12 and the source electrode 14a is supplied from the anode power supply circuit 53 to the organic light emitting diode OLED via the anode current supply wiring An and the organic thin film transistor Td for driving EL.
  • the organic light emitting diode OLED emits light and an image is displayed on the organic EL display device 200.
  • the body electrode 17a is connected to the anode current supply wiring An, so that the organic semiconductor is irradiated by light irradiation. Excess electrons accumulated in the layer 19a are sucked out from the anode current supply wiring An through the body electrode 17a.
  • the organic EL display device 200 can realize a stable TFT characteristic by suppressing a shift of a threshold voltage at the time of light irradiation or light OFF. As a result, in the organic EL display device 200, a stable display quality that is hardly affected by light such as external light or self-light emission can be obtained.
  • the organic EL display device 200 can be used for a display medium such as a display, and can be diverted to a light emitting device such as an illumination.
  • FIG. 68 is a diagram showing a second example of an equivalent circuit diagram of the organic EL display device shown in FIG. With reference to FIG. 68, an organic EL display device 200A according to the present embodiment will be described.
  • the organic EL display device 200A when compared with the organic EL display device 200 according to the twelfth embodiment, includes a constant potential power supply circuit 54 and a constant potential wiring HL. The difference is that the body electrode 17a is connected to the constant potential wiring HL, and the other configurations are substantially the same.
  • a plurality of constant potential wirings HL are provided between the adjacent scanning signal wirings GL so as to extend in parallel to the scanning signal wirings GL.
  • the organic semiconductor layer 19a included in the organic thin film transistor 1 When a p-type organic semiconductor layer is used as the organic semiconductor layer 19a included in the organic thin film transistor 1, a positive high voltage is applied to the body electrode via the constant potential wiring HL. Thereby, surplus electrons accumulated in the organic semiconductor layer 19a by light irradiation are sucked out from the constant potential wiring HL through the body electrode 17a. Since the constant potential wiring HL is a separate system from the anode current supply wiring An, it is possible to apply a voltage more suitable for extracting surplus electrons. Thereby, even in the organic EL display device 200A according to the present embodiment, an effect equal to or higher than that of the organic EL display device 200 according to the twelfth embodiment is obtained.
  • FIG. 69 is a diagram showing a third example of an equivalent circuit diagram of the organic EL display device shown in FIG. 66. With reference to FIG. 69, an organic EL display device 200B according to the present embodiment will be described.
  • the body electrode 17a of the organic thin film transistor Td is the cathode electrode (counter electrode 33) of the organic light emitting diode OLED. Or it is different in that it is connected to the cathode current supply wiring CA and in that the organic semiconductor layer 19a is formed of an n-type organic semiconductor layer, and the other configurations are substantially the same.
  • the body electrode 17a is connected to the cathode electrode (counter electrode 33) or the cathode current supply wiring CA.
  • the excess holes accumulated in the organic semiconductor layer 19a by the light irradiation are sucked out from the cathode current supply wiring CA through the body electrode 17a.
  • FIG. 70 is a schematic cross-sectional view showing a second embodiment of the organic EL display device including the thin film transistor substrate shown in FIG. 71 is a diagram showing a first example of an equivalent circuit diagram of the organic EL display device shown in FIG.
  • An organic EL display device 200C according to the present embodiment will be described with reference to FIGS.
  • the organic EL display device 200C according to the present embodiment differs from the organic EL display device 200 according to the twelfth embodiment in the configuration of the organic EL layer 36. Accordingly, the pixel electrode 25b is an anode electrode.
  • the counter electrode 35 formed on the organic EL layer 36 functions not as a cathode electrode but as an anode electrode, and instead of the anode power supply circuit and the anode current supply wiring, the cathode power supply circuit 55 and the cathode current are used.
  • the supply wiring CA is provided, and the other configurations are substantially the same.
  • the organic EL layer 36 is configured by laminating an electron transport layer (ETL), an EL light emitting layer (EM), and a hole transport layer (HTL) in this order.
  • ETL electron transport layer
  • EM EL light emitting layer
  • HTL hole transport layer
  • a reflective electrode such as Al, Al alloy, Ag, or Ag alloy can be employed as the material of the cathode electrode (pixel electrode 25b).
  • a transparent conductive film such as IZO, ITO, CNT, or graphene, or a thin metal film such as Au or Ag can be used (as a transparent counter electrode).
  • an ink containing nanoparticles such as Au, Ag, Cu, Al, IZO, ITO, CNT, and graphene can be employed.
  • a scanning signal is sent from the vertical operation circuit 50 to the gate electrode G of the switching organic thin film transistor Ts via the scanning signal wiring GL.
  • a video signal is supplied from the horizontal drive circuit 51 to the source electrode S of the organic thin film transistor Ts via the video signal wiring DL.
  • the signal supplied to the source electrode S is held in the charge storage capacitor Cs.
  • the holding voltage of the charge storage capacitor Cs is a voltage between the gate electrode 12 and the source electrode 14a of the EL driving organic thin film transistor Td.
  • a constant current corresponding to the voltage between the gate electrode 12 and the source electrode 14a is supplied from the anode electrode (counter electrode 35) to the organic light emitting diode OLED via the organic thin film transistor Td for driving EL.
  • the organic light emitting diode OLED emits light and an image is displayed on the organic EL display device 200C.
  • any of a p-type semiconductor layer and an n-type semiconductor layer can be used as the organic semiconductor layer 19a included in the organic thin film transistor 1 (organic thin film transistor Td for driving EL), as shown in FIG.
  • this is particularly effective when an n-type semiconductor layer is used. That is, even if the performance of the organic EL layer deteriorates due to long-term energization or moisture and the voltage at the anode end changes, the current between the gate electrode 12 and the source electrode 14a that determines the current flowing in the organic thin film transistor Td for driving the EL is changed. This is because the voltage is not affected, and a constant current can flow through the organic thin film transistor Td and the organic EL layer. Thereby, the organic EL display device 200C having uniform and stable luminance (display quality) is obtained.
  • the body electrode 17a is connected to the cathode current supply wiring CA, so that excess holes accumulated in the organic semiconductor layer 19a due to light irradiation pass through the body electrode 17a. Sucked from the cathode current supply wiring CA.
  • the organic EL display device 200C can realize a stable TFT characteristic by suppressing a shift of a threshold voltage during light irradiation or light OFF. As a result, in the organic EL display device 200C, it is possible to obtain a stable display quality that is hardly affected by light such as external light or self-light emission.
  • the surface treatment is performed only on the body electrode when the source electrode, the drain electrode, and the body electrode are made of the same material.
  • the present invention is not limited to this, and even in the first, third, fifth, and seventh embodiments, the surface treatment may be performed only on the body electrode even when the body electrode is formed of a material different from that of the source electrode and the drain electrode.
  • the source electrode, the drain electrode, and the body electrode are made of the same metal material, and only the body electrode is subjected to a surface treatment, whereby the source electrode and the drain electrode are formed.
  • the present invention is not limited to this, and the source electrode, the drain electrode, and the body electrode are made of the same metal material, and the n-type organic semiconductor layer and p
  • the work function of the source and drain electrodes and the body electrode is formed by forming body electrodes having different surface orientations from the surface orientation of the source and drain electrodes, regardless of which type of organic semiconductor layer is used. May be adjusted.
  • Table 1 shows the work function for each plane orientation and the work function of polycrystalline in each electrode material.
  • the value of the work function is a value disclosed in various documents and may vary depending on the experimental environment or the like, but is known to be approximately the value shown in Table 1 below.
  • the plane orientation of the main surfaces of the source electrode 4a and the drain electrode 14b is mainly used. It is formed so as to be (100), and the surface orientation of the main surface of the body electrode 17b is mainly (110).
  • the work function of the body electrode 17b is approximately 4.8 eV, and the work function of the body electrode 17b is a value close to the LUMO level (about 3.5 eV) of pentacene, which is the p-type organic semiconductor layer 19a. Can be made smaller.
  • the surfaces of the main surfaces of the source electrode 4a and the drain electrode 14b It is formed so that the orientation is mainly (100), and the surface orientation of the main surface of the body electrode 17b is mainly (111).
  • the work function of the body electrode 17b is approximately 5.3 eV, and the work function of the body electrode 17b is brought close to the HOMO level (about 6.2 eV) of the C60 fullerene that is the n-type organic semiconductor layer 19a. be able to.
  • the materials of the source electrode 14a, the drain electrode 14b, and the body electrode 17b and their plane orientations are not limited to the above description, and are appropriately selected based on Table 1 within a range that does not depart from the spirit of the present invention. can do. Similarly, even when the material of the source and drain electrodes and the material of the body electrode are different, those materials and plane orientations can be appropriately selected based on Table 1.

Abstract

L'invention concerne un transistor organique en couches minces (1) qui comprend : une électrode grille (12) ; une couche de semi-conducteur organique (19a) qui est agencée de sorte à être orientée vers l'électrode grille (12) ; un film isolant de grille qui est intercalé entre l'électrode grille (12) et la couche de semi-conducteur organique (19a) ; une électrode source (14a) et une électrode déversoir (14b) qui sont raccordées à la couche de semi-conducteur organique (19a) dans le but de fournir un courant électrique à la couche de semi-conducteur organique (19a) ; et une électrode corporelle (17a) qui est raccordée à la couche de semi-conducteur organique (19a) dans le but d'extraire des charges stockées dans la couche de semi-conducteur organique (19a).
PCT/JP2014/072889 2013-09-04 2014-09-01 Transistor organique en couches minces WO2015033881A1 (fr)

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