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WO2009013291A2 - Eléments à effet de champ - Google Patents

Eléments à effet de champ Download PDF

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Publication number
WO2009013291A2
WO2009013291A2 PCT/EP2008/059598 EP2008059598W WO2009013291A2 WO 2009013291 A2 WO2009013291 A2 WO 2009013291A2 EP 2008059598 W EP2008059598 W EP 2008059598W WO 2009013291 A2 WO2009013291 A2 WO 2009013291A2
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WIPO (PCT)
Prior art keywords
layer
field effect
effect element
dielectric layer
insulating layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2008/059598
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English (en)
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WO2009013291A3 (fr
Inventor
Ingolf Hennig
Florian DÖTZ
Peter Eckerle
Radoslav Parashkov
Marcel Kastler
Subramanian Vaidyanathan
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BASF SE
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BASF SE
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Publication of WO2009013291A3 publication Critical patent/WO2009013291A3/fr
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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 potential barriers
    • H10K10/40—Organic transistors
    • H10K10/46—Field-effect transistors, e.g. organic thin-film transistors [OTFT]
    • H10K10/462—Insulated gate field-effect transistors [IGFETs]
    • H10K10/468—Insulated gate field-effect transistors [IGFETs] characterised by the gate dielectrics
    • H10K10/471—Insulated gate field-effect transistors [IGFETs] characterised by the gate dielectrics the gate dielectric comprising only organic materials
    • 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 potential barriers
    • H10K10/40—Organic transistors
    • H10K10/46—Field-effect transistors, e.g. organic thin-film transistors [OTFT]
    • H10K10/462—Insulated gate field-effect transistors [IGFETs]
    • H10K10/468—Insulated gate field-effect transistors [IGFETs] characterised by the gate dielectrics
    • H10K10/474—Insulated gate field-effect transistors [IGFETs] characterised by the gate dielectrics the gate dielectric comprising a multilayered structure

Definitions

  • FET field effect transistors
  • a typical FET comprises several layers which may be adapted to the intended use. It typically contains a dielectric, a semiconductor, a source and a drain electrode electrically connected to the semiconductor and a gate electrode which are disposed on a substrate in a layer structure.
  • TFT thin film transistors
  • OTFT organic thin film transistor
  • the organic semiconductor in the OTFT has several advantages with respect to its inorganic counterpart. It can be processed in any shape from fiber to film, shows high mechanical flexibility, can be manufactured at a low cost and is of low weight.
  • the main advantage is the possibility to manufacture the whole semiconductor device by depositing the layer structure on a plastic substrate under atmospheric pressure, e.g. by printing, so that low-priced FET can be realized.
  • water or polar solvent processible dielectric materials are used.
  • these materials mostly contain polymers comprising hydrophilic functional groups like hydroxyl, ether, or ester groups.
  • these hygroscopic polymers have the tendency to incorporate water in amounts changing the characteristics of the dielectric layer dramatically, particularly in a top gate configuration where the hygroscopic insulator is deposited on top of the semiconducting layer.
  • WO 03/052841 discloses a layer structure for an OFET comprising a low-k non-polar organic insulating layer, which may be combined with a high-k organic layer.
  • the low-k layer is arranged to be in direct contact with the semiconducting layer.
  • US-A 2005/0001210 discloses a layer structure comprising a high k organic material being in direct contact with the gate electrode, which is combined with a low-k organic insulating layer.
  • a diffusion barrier layer containing both hydrophilic and hydrophobic groups is described.
  • the barrier layer protects the semiconducting layer and the insulating layer against unintentional doping by impurities and ionic diffusion during the deposition of the gate electrode.
  • the diffusion barrier layer may comprise a non-polar polymer, preferably a semiconducting non-polar conjugated polymer or a polyfluorene derivate. Since they were not exposed to humidity before testing there is no difference shown between the use of a diffusion barrier or non-use of it.
  • PVOH polyvinyl alcohol
  • the OTFT when using a multi-layered gate insulator including a dielectric layer and a hydrophobic insulating layer arranged between the gate electrode and the dielectric layer, the OTFT thus obtained exhibits low hysteresis during the whole lifetime.
  • a field effect element comprising
  • a source electrode and a drain-electrode - a semiconducting layer comprising an organic semiconductor compound being in contact with the source electrode and the drain electrode, a gate electrode, and a dielectric layer comprising one or more compounds selected from hygroscopic organic compounds and from nanoparticulate inorganic compounds being ar- ranged between the semiconducting layer and the gate electrode, wherein said hygroscopic organic compounds have a water absorption capability of more than 1.2 % by weight, and a hydrophobic insulating layer being arranged between the gate electrode and the dielectric layer preventing diffusion of water into the one or more hygroscopic compounds of the dielectric layer during the time of use of the field effect element, said hydrophobic insulating layer having a water absorption capability of less than 1.2 % by weight.
  • the semiconducting layer, the dielectric layer or the hydrophobic insulating layer, or a combination thereof must be disposable from a liquid.
  • Hygroscopic characterizes a material having a water absorption capability, i.e. a saturated water content at equilibrium, of more than 1.2 % by weight at a temperature of 22 0 C and a relative humidity of 47 %.
  • a water absorption capability i.e. a saturated water content at equilibrium
  • the water absorption capability is 1.5 % by weight or more, more preferably 2 % by weight or more, even more preferably 2.5 % by weight or more.
  • Most preferably the water absorption capability is 3 % by weight or more.
  • the hygroscopic material may be a single compound or a mixture of compounds.
  • the dielectric layer may also comprise a nanocomposite dielectric material comprising nanoparticulate inorganic materials, preferably metal oxides.
  • nanoparticu- late materials are Ta2 ⁇ s, Y2O5, Ti ⁇ 2, Ce ⁇ 2, Zr ⁇ 2.
  • these materials have to be bound in a polymer matrix of an insulating polymer as described for example in US 2005/0001210 A1. These polymers forming the matrix may be hygroscopic or non-hygroscopic.
  • the nanoparticulate inorganic materials preferably have a diameter of 1 to 100 nm without being restricted thereto.
  • the dielectric layer may also comprise any inorganic dielectric material as Si ⁇ 2, Spin on Glass (e.g. organosilane) or AI2O3.
  • the contact angle of the dielectric layer is 60° or less, more preferably 55° or less, most preferably 50° or less.
  • Hydrophobic in the meaning of the present invention characterizes a material having a water absorption capability of less than 1.2 % by weight at a temperature of 22 0 C and a relative humidity of 47 %.
  • the water absorption capability is 0.8 % or less, more preferably 0.6 % by weight or less.
  • the water absorption capability of the hydrophobic material is 0.4 % by weight or less.
  • the hydrophobic material forming the hydrophobic insulating may be a single compound or a mixture of compounds.
  • the water barrier layer prevents the hygroscopic dielectric layer being penetrated by water at least a factor 10, preferably a factor 100, most pre- ferably a factor 1000 slower than without the barrier layer.
  • the contact angle of the barrier layer is 60° or more, more preferably 62° or more, most preferably 64° or more.
  • the organic field effect element comprises:
  • a source electrode and a drain-electrode a semiconducting layer comprising an organic semiconductor compound being in contact with the source electrode and the drain electrode, - a dielectric layer, a hydrophobic insulating layer, and a gate electrode,
  • the field effect element can have one or more source electrodes and drain- electrodes, one or more semiconducting layers, one or more dielectric layer, one or more hydrophobic insulating layers, and one or more gate electrodes.
  • the organic field effect element comprises:
  • a semiconducting layer comprising an organic semiconductor compound, a source electrode and the drain-electrode, both being in contact with the semi- conducting layer , a dielectric layer, a hydrophobic insulating layer, and a gate electrode,
  • the whole dielectric structure may consist only of the dielectric layer comprising one or more compounds selected from hygroscopic organic compounds and from nanopar- ticulate inorganic compounds according to the present invention or may comprise fur- ther layers comprising insulating materials. Therefore the whole dielectric structure may be a mono, di, tri or multiple layer structure. It is preferred to have a low-k insulating layer being arranged between the semiconducting layer and the dielectric layer.
  • the present invention is particularly useful, if highly hygroscopic dielectrics are used, since they can easily be manufactured by printing from solutions containing water or highly polar solvents like alcohols. It is therefore most preferred for the dielectric layer to comprise polymers having at last one functional group containing at least one hydro- gen atom, said functional group being capable of forming hydrogen bonds with water. Such functional groups are normally capable of incorporating high amounts of water.
  • Particularly useful functional groups comprise elements selected from N, O, S and P. Particularly useful functional groups may be selected e.g. from amine, amide, hydroxyl, carboxyl, thiol or combinations thereof. These functional groups contain at least one hydrogen atom.
  • the semiconducting layer, the dielectric layer and the hydrophobic insulating layer essentially consist of organic compounds. It is particularly preferred to form the whole layer structure on a highly flexible organic polymer substrate like polyethylene terephthalate, polyethylene naphthalate or polyimide or mixture thereof without being restricted thereto.
  • the layer structure of the organic field effect element according to the present invention is preferably deposited by mass printing the dielectric layer preferably has a thickness of more than 50 nm, more preferably from 100 nm to 10,000 nm, most preferably from 200 nm to 8,000 nm.
  • the hydrophobic insulating layer has generally a thickness of from about 10 nm to about 1000 nm, preferably from about 50 to about 500 nm, most preferably from about 100 nm to about 300 nm.
  • a thicker hydrophobic insulating layer would decrease the overall dielectric layer formed by the dielectric layer and the hydrophobic insulating layer too much, a thinner hydrophobic insulating layer would not form a useful barrier to water during the use of the field effect element which may be months or years.
  • a process for preparing an organic field effect element comprising:
  • steps ii) and iii) may be carried out interchangeably and wherein the deposition in at least one of steps iii), iv) and v) is carried out from a liquid.
  • the steps are carried out sequentially.
  • the dielectric layer is deposited from a liquid comprising the semiconductor compound. It may be for example a solution or suspension of the dielectric material a solvent.
  • the dielectric layer is preferably deposited from a solution in an aprotic polar solvent.
  • the whole layer structure can be deposited by any process known in the art. However, it is preferred to deposit all the layers from a liquid, most preferably by a printing process.
  • the liquid may be any liquid capable of dissolving (one phase) or dispersing (at least two phases) the semiconducting compound, which does not strongly interact with the layer deposited below.
  • the semiconducting layer may be deposited from a solution comprising the semiconductor compound in a solvent.
  • the semiconducting layer is deposited from a dispersion or suspension comprising the semiconductor in a liquid.
  • the dielectric layer and the hydrophobic insulating layer may also be deposited from a suspension or preferably from a solution.
  • Particularly useful solvents for depositing the dielectric layer are protic solvents like water, alcohols or polar aprotic solvents like ketones, ethers without being restricted thereto. Alternatively, non-polar aprotic solvents may be used. Protic solvents are preferred.
  • the liquid for depositing the dielectric layer comprises 10 % by weight or more, preferably more than 20 %, particularly preferred more than 40% of water.
  • the field effect element is particularly useful for manufacturing of Radio Frequency Identification (RFID) devices, backplane display circuitry, or any integrated circuitry or drivers for memory arrays without being restricted thereto.
  • RFID Radio Frequency Identification
  • Fig. 1 a bottom contact/top gate arrangement of layers in an OTFT according to a preferred embodiment of the present invention.
  • Fig. 2 plots of the drain current as a function of gate voltage of an OTFT with a high-k dielectric and a hydrophobic insulation layer as prepared in Example 1 a) after exposition to air; b) in a glove box without exposition to air.
  • Fig. 3 plots of the drain current as a function of gate voltage of an OTFT with only a high-k dielectric layer as prepared in comparative Example A a) after exposition to air; b) in a glove box without exposition to air.
  • Fig. 1 a bottom contact/top gate arrangement of layers in an OTFT according to a preferred embodiment of the present invention.
  • Fig. 2 plots of the drain current as a function of gate voltage of an OTFT with a high-k dielectric and a hydrophobic insulation layer as prepared in Example 1 a) after exposition to air; b) in a
  • Fig. 4 plots of the drain current as a function of gate voltage of an OTFT with only a high-k dielectric and a hydrophobic insulation layer in "reverse order" as prepared in comparative Example B.
  • Fig. 5 plots of the drain current as a function of gate voltage of an OTFT with a sandwiched low-k/high-k/hydrophobic insulation layer arrangement as pre- pared in Example 2.
  • Fig. 1 schematically shows a preferred embodiment of the present invention representing a top gate layer structure of an organic field effect transistor.
  • any other layer structure can be used to realize the present invention, as long as the hydro- phobic insulating layer is arranged between the gate electrode and the high-k dielectric layer.
  • the layer structure comprises a substrate 1 on which source and a drain electrodes 6, 7 are formed. On top of the structure the gate electrode 5 is formed. In a bottom gate structure the positions of gate and source/drain electrodes are exchanged.
  • Materials for the substrate 1 can be any known materials in the art of field effect transistors.
  • the substrate is made of plastic, glass, quartz, or silicon, most preferably of thermoplastic polymers like Polyethylene terephthalate.
  • the gate electrode 5 and the source/drain electrodes 6, 7 can be any known materials in the art of the thin film transistors.
  • the gate and source/drain electrodes are made of inorganics like gold (Au), silver (Ag), aluminum (Al), nickel (Ni), indium thin oxide (ITO), but are not limited thereto.
  • the gate and source and drain electrodes can be manufactured from any conductive organic material, for example polyethylenedioxythiophene, polyaniline or polypyrrole.
  • a semiconducting layer 2 is formed on the substrate 1 or source 6 and drain 7, respectively.
  • the organic semiconducting layer 2 can be made of any materials known as an organic semiconductor including a conducting polymer.
  • the organic semiconducting layer is prepared from pentacene, copper phthalocyanine, polythiophene, polyaniline, polyacetylene, polypyr- role, polyphenylene vinylene or derivatives thereof, but is not limited thereto. Particularly preferred is polythiophene.
  • the organic semiconductor may be an n or p type.
  • Preferred organic semiconductors have a FET mobility of greater than 10" 5 Cm 2 V- 1 S" 1 , preferably greater than 10" 4 Cm 2 V" 1 c-1
  • the organic semiconductor may be any conjugated aromatic molecule containing at least three aromatic rings.
  • Preferred organic semiconductors contain 5, 6 or 7 mem- bered aromatic rings, especially preferred organic semiconductors contain 5 or 6 mem- bered aromatic rings.
  • Each of the aromatic rings may optionally contain one or more hetero atoms selected from Se, Te, P, Si, B, As, N, O or S, preferably from N, O or S.
  • the rings may be optionally substituted with alkyl, alkoxy, polyalkoxy, thioalkyl, acyl, aryl or substituted aryl groups, a fluorine atom, a cyano group, a nitro group or an optionally substituted secondary or tertiary alkylamine or arylamine -N(R 3 )(R 4 ), where R 3 and R 4 each independently is H, optionally substituted alkyl, optionally substituted aryl, alkoxy or polyalkoxy groups.
  • the alkyl and aryl groups may be optionally fluorinated.
  • T1 and T2 each independently represent H, Cl, F, -C ⁇ N or lower alkyl groups particularly C1-4 alkyl groups; R' represents H, optionally substituted alkyl or optionally substituted aryl.
  • the alkyl and aryl groups may be optionally fluorinated.
  • organic semi-conducting materials that can be used in this invention include compounds, oligomers and derivatives of compounds of the following list: conjugated hydrocarbon polymers such as polyacene, polyphenylene, poly (phenylene vinylene), polyfluorene including oligomers of those conjugated hydrocarbon polymers ; condensed aromatic hydrocarbons such as anthracene, tetracene, chrysene, pentacene, pyrene, perylene, coronen; oligomeric para substituted phenylenes such as p- quater- phenyl (p-4P), p-quinquephenyl (p-5P), p-sexiphenyl (p-6P); conjugated heterocyclic polymers such as poly (3-substituted thiophene), poly (3, 4-bisubstituted thiophene), polybenzothiophene, polyisothianapthene, poly(N-substituted pyrrole
  • the semiconducting channel may also be a composite of two or more of the same types of semiconductors.
  • a p type channel material may, for example be mixed with n-type materials for the effect of doping the layer.
  • Multilayer semiconducting layers may also be used.
  • the semiconductor may be intrinsic near the insulator interface and a highly doped region can additionally be coated next to the intrinsic layer.
  • a dielectric layer 3 is formed on the semiconducting layer 2.
  • the dielectric layer 3 is preferably composed of one ore more materials having both high dielectric constant (k) and excellent insulating properties.
  • the dielectric layer has a k-value above 3, preferably above 4, more preferably above 5, more preferably above 10, most preferably above 20, for example between 20 to 200 to maximise the gate capacitance.
  • the dielectric layer is made of organic polymers having a k-value sufficiently high, or alternatively, additives may be added to increase the k-value.
  • Insulating organic polymers particularly useful for preparing the dielectric layer include highly hygroscopic insulating polymers.
  • the useful dielectric materials include, but are not limited to, polyester, polycarbonate, polyvinylalcohol, polyvinylphe- nol, polyvinylbutyral, polyacetal, polyarylate, polyamide, polyamidimide, polyetherimide, polyphenylenether, polyphenylenesulfide, polyethersulfone, polyetherketone, polyphthalamide, polyethernitrile, polyethersulfone, polybenzimidazole, polycarbodiim- ide, polysiloxane, polymethylmethacrylate, polymethacrylamide, nitrile rubbers, acryl rubbers, polyethylenetetrafluoride, epoxy resins, phenol resins, melamine resins, urea resins, polybutene, polypentene, poly(ethylene-co-propylene), poly(ethylene-co- butenediene), polybutad
  • the insulating layer is essentially formed by one or more organic polymers having a dielectric constant of 5 or higher, like polyester, polycarbonate, polyvinylalcohol, polyvinylbutyral, polyacetal, polyarylate, polyvinylphenol, cyanoethylated polysaccharides such as cyanoethylpullulane, polyvi- nylidenefluoride, polyurethane polymers and poly (vinyl chloride/vinylacetate) polymers, and mixtures thereof without being restricted thereto.
  • organic polymers having a dielectric constant of 5 or higher, like polyester, polycarbonate, polyvinylalcohol, polyvinylbutyral, polyacetal, polyarylate, polyvinylphenol, cyanoethylated polysaccharides such as cyanoethylpullulane, polyvi- nylidenefluoride, polyurethane polymers and poly (vinyl chloride/vinylacetate) polymers, and
  • the dielectric layer 3 may generally be of any thickness, for example 50 nm to 20 ⁇ m.
  • the present invention is particularly useful if thicknesses of more than about 500 nm are used since the hysteresis effects due to water incorporation into the hygroscopic dielectric layer are much higher than for thinner layers.
  • the thickness of the dielectric layer is from about 100 nm to about 10 ⁇ m, more preferably from about 500 nm to about 10 ⁇ m, more preferably from about 600 nm to about 9 ⁇ m, more preferably from about 700 nm to about 8 ⁇ m, more preferably from about 800 nm to about 7.5 ⁇ m, more preferably from about 900 nm to about 7 ⁇ m, most preferably from about 1 ⁇ m to about 6 ⁇ m.
  • the dielectric layer is preferably deposited by a wet process, most preferably from a solution by printing.
  • a hydrophobic insulating layer 4 is formed on the dielectric layer 3.
  • the hydrophobic insulating layer is arranged between the gate electrode and the dielectric layer 3.
  • the hydrophobic insulating layer 4 essentially consists of one or more hydrophobic insulating materials.
  • the hydrophobic insulating layer 4 consists essentially of an organic material, e. g. a polymer.
  • examples of polymers useful to form the hydrophobic insulating layer are non-polar polymers like polystyrene.
  • the hydrophobic material may be porous if its barrier function to water is not negatively influenced. However, it is preferred to have non-porous materials since the thickness of the layers may be reduced.
  • the thickness of the hydrophobic insulating layer is normally from about 5 nm to about 5 ⁇ m, preferably from about 10 nm to about 1000 nm, most preferably from about 50 nm to about 500 nm.
  • the total effective dielectric constant k of the whole insulator can be adjusted by controlling the thickness of the dielectric layer 3 and the hydrophobic insulating layer 4.
  • the thickness of the dielectric layer is greater than the thickness of the hydrophobic insulating layer to ensure an overall high-k value.
  • the thickness of the dielectric layer is more preferably 5 times or more, most preferably 10 times or more of the thickness of the hydrophobic insulating layer.
  • Typical polymers having low water capability useful for the hydrophobic insulating layer are (without limiting to these examples): Fluorinated para-xylene, Fluoropolyarylether, Fluorinated polyimide, Polystyrene, Poly ( ⁇ -methyl styrene), Poly ( ⁇ -vinylnaphtalene), Poly (vinyltoluene), Polyethylene, cis-polybutadiene, Polypropylene, Polyisoprene, Poly (4-methyl-1-pentene), Poly (tetrafluoroethylene), Poly (chorotrifluoroethylene), Poly (2- methyl-1 , 3-butadiene), Poly (p-xylylene), Poly ( ⁇ - ⁇ - ⁇ '- ⁇ ' tetrafluoro-p-xylylene), Poly [1 , 1-(2-methyl propane) bis (4-phenyl) 2.
  • copolymers can be used.
  • Some examples of copolymers are Poly (ethylene/tetrafluoroethylene), Poly (ethylene/chlorotrifluoroethylene), Fluorinated ethylene/propylene copolymer, Polystyrene-co- ⁇ -methyl styrene, Ethylene/ethyl acry- late copolymer, Poly (styrene/10 % butadiene), Poly (styrene/15 % butadiene), Poly (styrene/2, 4 dimethylstyrene), Cytop 2.0 Teflon AF (Du Pont), Polypropylene-co-1- butene. Both random or block copolymers can be used. It is also possible to add some more polar monomer components as long as the overall composition remains sufficiently impermeable to water.
  • Preferred hydrophobic materials are polypropylene, preferably amorphous polypropylene, or fluoropolymers, for example copolymers of tetrafluoroethylene and dioxoles such as 2, 2 bistrifluoromethy- 4, 5-difluoro-1 , 3-dioxole.
  • Other preferred materials are low permittivity fluoropolymers, fluoroepoxy polymers, fluorosilane, fluoroacryclic polymers, and poly (dimethyl) siloxane and its copolymers. Particularly useful is poly(styrene-butadiene-styrene) block copolymer.
  • the polymer may optionally be cross-linked after its deposition by heat or radiation.
  • intermediate layers can be deposited between the hydrophobic and a high-k dielectric layer of a multilayer insulator stack.
  • Such intermediate layers can improve adhesion or wetting between deposition steps.
  • the intermediate layer for example can be another tow permittivity material with different surface properties.
  • Surface treatments, for example plasma treatment, may also be used to improve layer compatibility.
  • a layer of low-k insulating material may be arranged between the semiconducting layer 2 and the dielectric layer 3.
  • the charge mobility of the structure can be increased in this way.
  • the low-k insulating material may be the same as used for the hydrophobic insulating layer or different.
  • the hydrophobic insulating layer as well as the dielectric layer and semiconducting layer are preferably deposited by a wet process, most preferably from a solution of the one or more hydrophobic insulating, dielectric or semiconducting compounds, respectively, in a solvent.
  • Useful wet processes are dip coating, spin coating, printing, spray coating, or roll coating techniques, but the present invention is not limited thereto. Deposition by printing is preferred. If both the semiconducting layer and the dielectric layer(s) are deposited from solution large areas can be coated.
  • an FET structure of Fig. 1c is prepared by spin coating the semiconductor onto the substrate with pre-patterned drain and source electrodes.
  • an insulator in the form of a low permittivity polymer of relative permittivity below 3 is spin coated onto the semiconductor followed by the deposition of the gate elec- trode by vacuum evaporation or liquid deposition of a conductive solution or dispersion. It will be appreciated that the order of process steps may be altered to achieve different structures. It will be appreciated that the OFET could also have a vertical structure. All percent values refer to the weight with respect to the total weight of the respective mixture. All cited documents are incorporated herein by reference.
  • the thickness of the layers was determined by profilometry.
  • the dielectric constant for the dielectric layer was determined by measuring the capacitance between the gate electrode and the source and drain electrodes at 20 Hz.
  • the water content of the dielectric layer material and the barrier layer material was measured by Karl Fischer titration according to the following procedure:
  • the samples were heated under vacuum for about 18 h to 160 0 C. Then they were conditioned at 22 0 C and 47 % humidity (relative) for 24 hours.
  • the water was removed from the samples in a reactor at 250 0 C and sampled.
  • the amount of collected water was determined by Karl-Fischer titration.
  • An organic field effect transistor having a top gate, bottom source/drain structure com- prising a hydrophobic insulating layer according to Fig. 1 Structure a) was prepared by the following steps:
  • the source electrode 6 and the drain electrode 7 were made of a polyethylenedi- oxythiophene/polystyrene sulfonate (PEDOT/PSS) patterned polyethyl- eneterephtalate (PET) film substrate 1.
  • the film was patterned by means of laser ablation.
  • the channel width and length of the thin film transistors (TFTs) were 39 500 and 142 ⁇ m, respectively.
  • the PEDOT/PSS film thickness was 70 nm.
  • the next step of fabrication of the devices was the deposition of the active semi- conducting layer 2.
  • 1 -methyl hexyl thiophene oligomer (BASF) was deposited by spin coating at 3000 rpm from a solution of 4 g in 100 ml tetrahydrofuran. After the deposition the film was heated to 150 0 C for 10 min, afterwards the temperature was decreased to 135 0 C and held for one hour.
  • the dielectric layer 3 was prepared by spin coating a solution of polyvinyl alcohol (PVOH) 15 % by weight solution in a wate ⁇ butylglycol (95:5) and dried at 80 0 C for 30 min.
  • the thickness of the dielectric layer 3 was 3600 nm.
  • the hydrophobic insulating layer 4 was deposited by spincoating of a 5 % by weight solution of hydrogenated poly(styrene-butadiene-styrene) block copolymer (ZK 2604/046H, BASF) in heptane and dried for 5 min at 80 0 C.
  • the thickness of the hydrophobic insulating layer 4 was 200 nm.
  • a silver gate electrode 5 was dispensed above the conducting channel of the transistor using commercially available silver ink dispersion (Ag dispersion in toluene). Before the measurements the devices were dried for 10 min at 80 0 C.
  • each step 1.1 to 1.5 may be used independently of the other steps.
  • Fig. 2 shows the transfer electrical characteristics of a the OTFT with a hydrophobic dielectric layer 4 between the gate electrode 5 and the dielectric layer 3.
  • the hysteresis observed at drain-source voltages of -10 V was about 1 V.
  • the capacitance value was typically around 1 nF/cm 2 .
  • An organic field effect transistor having a top gate, bottom source/drain structure having no hydrophobic insulating layer was prepared.
  • Example 1 was reproduced with the only exception that step 1.4 was skipped.
  • Fig. 3a shows the transfer electrical characteristics of the OTFT without a hydrophobic insulating layer after exposition to air.
  • the hysteresis observed at drain-source voltages of -10 V was about 60 V.
  • the capacitance value was typically around 1 nF/cm 2 .
  • Fig. 3b shows the transfer electrical characteristics of the OTFT without exposure to air.
  • the hysteresis is as good as the structure with hydrophobic layer indicating that the hysteresis is not caused by the manufacturing process but by the exposure to humidity later on.
  • An organic field effect transistor having a top gate, bottom source/drain structure and comprising a dielectric layer arranged between the hydrophobic insulating layer and the gate electrode (reverse order) was prepared.
  • Example 1 was reproduced with the only exception that a 4% by weight solution of polytriarylamine (PTPA3, BASF) in tetrahydrofuran was used in step 1.2 and the steps 1.3 and 1.4 were carried out in reverse order, i.e. the dielectric layer was deposited after the hydrophobic insulating layer.
  • PTPA3, BASF polytriarylamine
  • Fig. 4 shows the transfer electrical characteristics of the OTFT with a hydrophobic dielectric layer in ..reverse order".
  • the hysteresis observed at drain-source voltages of -10 V was about 30 V.
  • the capacitance value was typically around 1 nF/cm 2 .
  • An organic field effect transistor having a top gate, bottom source/drain structure and comprising two hydrophobic insulating layers, arranged to sandwich a high-k dielectric layer, was prepared.
  • Example 1 was reproduced with the only exception that a 4 % by weight solution of polytriarylamine (PTPA3, BASF) in tetrahydrofuran was used in step 1.2 and that step 1.3 was carried out again after step 1.4, i.e. a sandwiched hygroscopic/hydrophobic dielectric/hydrophobic insulating structure was prepared.
  • PTPA3, BASF polytriarylamine
  • Fig. 5 shows the transfer electrical characteristics of the OTFT with this sandwiched layer structure.
  • the hysteresis observed at drain-source voltages of -10 V was about 20 V.
  • the capacitance value was typically around 1 nF/cm 2 .

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  • Silicon Compounds (AREA)

Abstract

L'invention concerne un élément à effet de champ qui comporte: une électrode de source (6) et une électrode déversoir(7), une couche de semi-conducteur (2) comportant un composé semi-conducteur en contact avec l'électrode de source (6) et l'électrode déversoir (7), une électrode de grille (5) et une couche diélectrique (3), comportant un ou plusieurs composés sélectionnés parmi des composés organiques hygroscopiques et/ou parmi des composés inorganiques nanoparticulaires, agencée entre la couche de semi-conducteur (2) et l'électrode de grille (5), lesdits composés organiques hygroscopiques ayant une capacité d'absorption d'eau supérieure à 1,2% en poids, et une couche isolante hydrophobe (4) agencée entre l'électrode de grille (5) et la couche diélectrique (3) empêchant la diffusion de l'eau dans le ou les composés hygroscopiques de la couche diélectrique pendant la durée d'utilisation de l'élément à effet de champ, ladite couche isolante hydrophobe (4) ayant une capacité d'absorption d'eau inférieure à 1,2% en poids, la couche de semi-conducteur (2), la couche diélectrique (3) ou la couche isolante hydrophobe (4), ou une combinaison de celles-ci, pouvant être disposées à partir d'un liquide. L'invention concerne également un procédé pour la fabrication de cet élément.
PCT/EP2008/059598 2007-07-25 2008-07-22 Eléments à effet de champ Ceased WO2009013291A2 (fr)

Applications Claiming Priority (2)

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EP07113135.3 2007-07-25
EP07113135 2007-07-25

Related Child Applications (2)

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US12/601,075 A-371-Of-International US20100159583A1 (en) 2007-05-23 2008-05-19 Apparatus for producing feeds comprising dried and fermented animal and plant residues and dried and fermented fertilizers
US13/594,960 Continuation-In-Part US8409855B2 (en) 2007-05-23 2012-08-27 Apparatus for producing feeds comprising dried and fermented animal and plant residues and dried and fermented fertilizers

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WO2009013291A3 WO2009013291A3 (fr) 2009-04-02

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Cited By (3)

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WO2010136385A1 (fr) * 2009-05-25 2010-12-02 Basf Se Diélectriques réticulables et leurs procédés de préparation et d'utilisation
US8877657B2 (en) 2009-04-28 2014-11-04 Basf Se Process for producing semiconductive layers
US9129801B2 (en) 2009-06-16 2015-09-08 Basf Se Thermally labile precursor compounds for improving the interparticulate contact sites and for filling the interstices in semiconductive metal oxide particle layers

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US9233842B2 (en) * 2013-03-15 2016-01-12 Robert Bosch Gmbh Passivation layer for harsh environments and methods of fabrication thereof
TWI576357B (zh) * 2015-10-20 2017-04-01 國立台灣大學 以醣類做為電荷儲存層之記憶體單元

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BR0016660A (pt) * 1999-12-21 2003-02-25 Plastic Logic Ltd Método para formar um transistor, transistor, e circuito lógico e dispositivo de exibição ou de memória
KR100949304B1 (ko) * 2001-12-19 2010-03-23 메르크 파텐트 게엠베하 유기 절연체를 포함하는 유기 전계 효과 트랜지스터
JP4450214B2 (ja) * 2005-03-11 2010-04-14 セイコーエプソン株式会社 有機薄膜トランジスタ、電子デバイスおよび電子機器
WO2006097566A1 (fr) * 2005-03-18 2006-09-21 Avantone Oy Procedes et agencements permettant d'acquerir et d'utiliser une conduction electronique dans un transistor organique en couches minces
US20070075308A1 (en) * 2005-09-30 2007-04-05 Florian Dotz Active semiconductor devices

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8877657B2 (en) 2009-04-28 2014-11-04 Basf Se Process for producing semiconductive layers
WO2010136385A1 (fr) * 2009-05-25 2010-12-02 Basf Se Diélectriques réticulables et leurs procédés de préparation et d'utilisation
US8853820B2 (en) 2009-05-25 2014-10-07 Basf Se Crosslinkable dielectrics and methods of preparation and use thereof
US9129801B2 (en) 2009-06-16 2015-09-08 Basf Se Thermally labile precursor compounds for improving the interparticulate contact sites and for filling the interstices in semiconductive metal oxide particle layers

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TW200924192A (en) 2009-06-01

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