Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
  • H10K85/60—Organic compounds having low molecular weight
  • H10K85/615—Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
  • H10K85/623—Polycyclic condensed aromatic hydrocarbons, e.g. anthracene containing five rings, e.g. pentacene
• • 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
  • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
  • H10K85/40—Organosilicon compounds, e.g. TIPS pentacene
• • 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]
  • H10K10/466—Lateral bottom-gate IGFETs comprising only a single gate
• • 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]
  • H10K10/484—Insulated gate field-effect transistors [IGFETs] characterised by the channel regions
  • H10K10/488—Insulated gate field-effect transistors [IGFETs] characterised by the channel regions the channel region comprising a layer of composite material having interpenetrating or embedded materials, e.g. a mixture of donor and acceptor moieties, that form a bulk heterojunction

Definitions

• This invention relates to bottom gate thin film transistors including the semiconductor of the present disclosure.
• the semiconductor may be solvent coated over previously generated layers of the transistor during manufacture.
• WO 2005/055248 A2 purportedly discloses certain substituted pentacenes and polymers in top gate thin film transistors.
• the present invention provides a transistor comprising: a substrate; a gate electrode; a semiconducting material not located between the substrate and the gate electrode; a source electrode in contact with the semiconducting material; a drain electrode in contact with the semiconducting material; and a dielectric material in contact with the gate electrode and the semiconducting material; wherein the semiconducting material comprises: 1-99.9% by weight of a polymer having a dielectric constant at IkHz of greater than 3.3; 0.1-99% by weight of a compound according to Formula I:
• each R* is independently selected from H and CH3, more typically H 5 and each R.2 is independently selected from branched or unbranched C2-C18 alkanes, branched or unbranched Cl -C 18 alkyl alcohols, branched or unbranched C2-C18 alkenes, C4-C8 aryls or heteroaryls, C5-C32 alkylaryl or alkyl-heteroaryl, a ferrocenyl, or more typically SiR ⁇ where each R ⁇ is independently selected from hydrogen, branched or unbranched C 1-C 10 alkanes, branched or unbranched Cl-ClO alkyl alcohols or branched or unbranched C2 ⁇
• ClO alkenes where more typically each R-* is independently selected from branched or unbranched Cl-ClO alkanes. Most typically the compound according to formula I is 6,13- bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene).
• the polymer having a dielectric constant at IkHz of greater than 3.3 is typically selected from the group consisting of: poly(4-cyanomethyl styrene) andpoly(4-vinylphenol) and most typically is poly(4- vinylphenol).
• Typical polymers may also include polymers containing cyano groups such as cyanopullulans.
• the source and drain electrodes may be in contact with the dielectric material or not in contact with the dielectric material.
• Fig. 1 is a schematic depiction of the layers present in a top contact/bottom gate thin film transistor.
• Fig. 2 is a schematic depiction of the layers present in a bottom contact/bottom gate thin film transistor.
• Fig. 3 is a schematic depiction of the layers present in a top contact/top gate thin film transistor.
• Fig. 4 is a schematic depiction of the layers present in a bottom contact/top gate thin film transistor.
• Thin film transistors show promise in the development of lightweight, inexpensive and readily reproduced electronic devices, in particular where they may be made by solvent coating techniques, such as printing techniques.
• Thin films transistors are known in four principle geometries. With reference to each of Fig. 1, representing atop contact/bottom gate thin film transistor, Fig. 2, representing a bottom contact/bottom gate thin film transistor, Fig. 3, representing a top contact/top gate thin film transistor, and Fig. 4, representing a bottom contact/top gate thin film transistor, thin film transistor 100 includes substrate 10, gate electrode 20, dielectric layer 30, semiconductor layer 40, source electrode 50, and drain electrode 60. Typically, each of the source electrode 50 and drain electrode 60 will overlap the gate electrode 20 to a slight extent.
• the gate electrode 20 is above the dielectric layer 30 and both the gate electrode 20 and the dielectric layer 30 are above the semiconductor layer 40.
• the gate electrode 20 is below dielectric layer 30 and both the gate electrode 20 and the dielectric layer 30 are below the semiconductor layer 40.
• the materials of the present invention permit the construction of a bottom gate transistor with a solvent coated semiconductor, due to the formulation of a semiconductor coating composition that can be coated over the dielectric.
• the semiconductor layer of the thin film transistor of the present disclosure may be made by any suitable method, including solvent coating methods, but also including dry methods, melt processing, vapor deposition, or the like.
• the materials of the semiconductor layer may be carried in any suitable solvent, which may include ketones, aromatic hydrocarbons, and the like.
• the solvent is organic.
• the solvent is aprotic.
• the semiconductor layer according to the present disclosure includes a functionalized pentacene compound according to Formula I:
• each R ⁇ is independently selected from H and CH3 and each R ⁇ is independently selected from branched or unbranched C2-C18 alkanes, branched or unbranched Cl-Cl 8 alkyl alcohols, branched or unbranched C2-C18 alkenes, C4-C8 aryls or heteroaryls, C5-
• each R ⁇ is independently selected from hydrogen, branched or unbranched Cl-ClO alkanes, branched or unbranched Cl-ClO alkyl alcohols or branched or unbranched C2-C10 alkenes.
• each R* is H.
• each R ⁇ is SiR ⁇ . More typically each R ⁇ is SiR ⁇ and each R ⁇ is independently selected from branched or unbranched Cl-ClO alkanes.
• the compound is 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene), shown in formula II:
• the semiconductor layer contains the compound of Formula I or of Formula II in an amount of 0.1-99% by weight, more typically 0.1-10%.
• the semiconductor layer according to the present disclosure includes a polymer having a dielectric constant at IkHz of greater than 3.3, and more typically greater than 3.5, and in some embodiments may be greater than 4.0, and in some embodiments may be greater than 4.5.
• the polymer typically has a M.W. of at least 1,000 and more typically at least 5,000.
• Typical polymers include poly(4-cyanomethyl styrene) and poly(4- vinylphenol).
• Typical polymers may also include polymers containing cyano groups such as cyanopullulans.
• Typical polymers also include those described in U.S. Patent Publication No. 2004/0222412 Al .
• Polymers described therein include substantially nonfluorinated organic polymers having repeat units of the formulas:
• each R 1 is independently H, Cl 5 Br, I, an aryl group, or an organic group that includes a crosslinkable group
• each R 2 is independently H, an aryl group, or R 4
• each R 3 is independently H or methyl
• each R 5 is independently an alkyl group, a halogen, or R 4
• each R 4 is independently an organic group comprising at least one CN group and having a molecular weight of about 30 to about 200 per CN group
• n 0-3; with the proviso that at least one repeat unit in the polymer includes an R 4 .
• the semiconductor layer contains the polymer in an amount of 1-99.9% by weight.
• Polymer A is a nitrile-containing styrene-maleic anhydride copolymer that is described in U.S. Patent Publication No. 2004/0222412 AL The synthesis is described therein at paragraphs 107 and 108 under the caption "Example 1, Synthesis of Polymer 1," as follows:
• TIPS-pentacene 6,13-bis(triisopropylsilylethynyl)pentacene
• Formula II 6,13-bis(triisopropylsilylethynyl)pentacene
• a high dielectric constant polymer was made with the compositions indicated in Table I.
• TIPS-pentacene was synthesized as disclosed in U.S. 6,690,029 Bl at Example 1.
• Poly(4-vinylphenol) MW 9,000 to 11,000 Sp.gr. 1.16 (PVP) was obtained from Polyscience, Inc. Warrington, PA.
• Poly(4-cyanomethyl styrene) was made by the method described for "polymer 4" in U.S. Patent Publication No. 2004/0222412 Al . All solutions were prepared by mixing the components overnight and filtering the resulting mixture through a 0.2 micron filter.
• Test transistors examples 1-10 were made on single crystal (i.e., ⁇ 100> orientation), heavily doped, p-type silicon wafers that were obtained from Silicon Valley Microelectronics (San Jose, CA).
• the wafers as purchased have a 1000 A layer of high temperature thermal silicon oxide layer on one face and a 5000 A layer of aluminum metal vapor deposited on the opposite face.
• the doped wafer capped with aluminum served as the gate electrode and the silicon oxide functioned as the gate dielectric when organic thin film transistors (OTFTs) were prepared.
• solution A, B, C, D or E was applied by either spin coating or knife coating method followed by either air drying or an anneal step (heating to 120 0 C for 10 minutes), as noted in Table II.
• Knife coating was accomplished with a Gardco 4" micron film coater by application of a portion of the solution to the knife edge and pulling the coated over the substrate.
• Spin coating was accomplished according to the following protocol: 1st stage 500 RPM for 10 sec Acceleration 2 (166 rpm/sec), 2nd stage 2000 RPM for 20 sec
• the devices were completed by patterned vapor deposition of gold source and drain electrodes through a shadow mask onto the semiconductor layer.
• the devices had a channel length of 60 to 100 ⁇ m and a channel width of 1000 ⁇ m.
• Bottom contact device example 9 was made by patterned vapor deposition of gold source and drain electrodes through a shadow mask onto the dielectric to give a channel length of 60 to 100 ⁇ m and a channel width of 1000 ⁇ m.
• the semiconductor was then knife coated over the entire structure.
• Bottom contact device examples 10 and 11 were made by first inkjet printing silver nanoparticle ink onto the dielectric layer (InkJet Silver Conductor, AG-IJ-100-Sl, bulk resistivity 4-32 ⁇ cm, from Cabot Printable Electronics and Displays, Albuqerque, New Mexico, Batch AG-062005-A). The sample was then cured at 125°C for 11 minutes followed by treating the sample with a 0.1 mmol solution of perfluorothiophenol in toluene for 1 hour. The indicated semiconductor solution was deposited by knife coating over the entire structure and the sample was allowed to air dry or annealed at 120 0 C for 10 minutes.
• Transistor performance was tested at room temperature in air using a Semiconductor Parameter Analyzer (model 4145 A from Hewlett-Packard, Palo Alto, California).
• the square root of the drain-source current (Id 5 ) was plotted as a function of gate-source bias (Vg S ), from +10 V to -40 V for a constant drain-source bias (Vds) of -40 V.
• Vg S gate-source bias
• Vds constant drain-source bias

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• Chemical & Material Sciences (AREA)
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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Thin Film Transistor (AREA)

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• 2005
  • 2005-12-28 US US11/275,367 patent/US7514710B2/en not_active Expired - Fee Related
• 2006
  • 2006-12-21 EP EP06847918A patent/EP1969621A4/en not_active Withdrawn
  • 2006-12-21 JP JP2008548628A patent/JP2009522781A/ja active Pending
  • 2006-12-21 WO PCT/US2006/048804 patent/WO2007078993A1/en not_active Ceased
  • 2006-12-21 CN CN2006800492813A patent/CN101346808B/zh not_active Expired - Fee Related

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