DE102014003599A1 - Process for the preparation of functional layers - Google Patents

Abstract

The invention relates to a process for producing functional structures by evaporation or sublimation of precursor compounds from a donor ribbon and deposition on a substrate, and to corresponding donor bands.

Description

The invention relates to a method for producing functional structures, to the use of the method for the production of scratch-resistant surface coatings or of layers for electronic components and to a donor band which can be used in the method according to the invention.

In established processes for the production of layers, such as electrical metal-oxide layers, the deposition in vacuum (eg CVD, sputtering) or a deposition or printing process is applied by means of a formulation.

Deposition in a vacuum requires complex and expensive process equipment with vacuum technology. The speed of component production is low. As a result, the costs are relatively high overall. For structuring shadow masks are used to shield the non-coated areas or, after a full-surface coating, a subsequent etching process used.

In printing processes, the formulation consists of the starting material to be printed and a carrier material, eg. As solvent, resin or wax, which are transferred to a substrate to be coated. A major problem here is finding suitable solvents that dissolve the starting material and their formulation in order to allow good wetting on the substrate to be printed, but without dissolving the substrate. In order to adapt the formulation to the printing process, further additives or changes of the starting material may be necessary, for example increasing the viscosity or improving the wetting on a certain substrate. This can adversely affect the electrical function of the applied layer ( McCulloch; Chem. Mater. 17 (2005) 1381-1385 ).

In the case of application from solution, the carrier material must then be removed again in order to ensure the functionality of the layers. This often results in defects or other defects in the layer, which limit the quality of the subsequent component ( Bornemann; J. Imaging Sci. Technol. 55 (4): 040201-1-8, 2011 ). Thus, there continues to be a need for methods that enable the production of high quality functional structures, such as layers or patterned layers, in a technically easy-to-handle manner. Accordingly, auxiliary materials such as solvents or binders should be avoided as much as possible. Good wetting and coating quality should be obtained on the substrate. In the best case, the process should be feasible under normal environmental conditions including present gases and moisture. In addition, the structuring or the layout of the applied layer should be finely and flexibly controllable.

A first aspect of the present invention is therefore a process for producing functional structures by evaporating or sublimating precursor compounds from a donor ribbon and depositing on a substrate.

A further subject of the present invention is a donor ribbon suitable for evaporation or sublimation processes, such as, for example, dye sublimation printing, characterized in that it has a support material to which precursor compounds have been applied.

This donor band coated with precursor compounds can be produced in a preferred process variant in a first step of the process according to the invention.

As support material for the donor ribbon, conventional materials can be used. It is advantageous if a film with a thickness in the range 0.1 .mu.m to 1 mm is selected and a support material is used which is chemically stable up to 50.degree. C. above the sublimation temperature of the material to be applied. It may be preferred if the material is also mechanically stable at this temperature.

If a high spatial resolution is required in the structuring, it is preferable to use as a material for the donor ribbon a material with a low thermal conductivity in the plane of the donor ribbon.

Suitable materials as carrier material for the donor belt are, for example, paper, thin glass, metal foil or polymer film. If a polymer film is used, it is preferred according to the invention if it is selected from polyethylene terephthalate, polyethylene, polypropylene or polyimide films.

Such a coated donor belt does not necessarily have to be designed as a web, other forms, such. B. in the form of a bow are possible.

The donor band can have a multilayer structure in a variant of the invention. Thus, the precursor material can be applied in multiple layers, wherein the different layers can consist of the same but also different materials. In addition to the precursor material more layers may be required, for. B. to control the wettability of the material carrier, for Coupling or improving the coupling of the thermal source or to protect the precursor material from damage or oxidation / aging.

The donor ribbons may be packaged in a protective package as an overall tape (i.e., roll or sheet) to protect against oxidation / aging. This packaging can then also be filled with inert gas. As an alternative to protecting the precursor material, the coated donor ribbon can also be provided with a protective layer on one or both sides. This protective layer can either remain on the material carrier during the transfer process (for example if it does not absorb the thermal source) or the protective layer is removed shortly before the transfer process.

For the production of the donor tapes a variety of process technologies (CVD, PVD, doctoring, printing, coating) can be used. If several layers are applied, then different process technologies can also be used.

A donor ribbon may be coated after the coating process with only a single precursor material or divided into regions of any size and arrangement with different precursor materials.

In principle, all uniform and coatable surfaces are suitable as substrate for the deposition of the functional structures. In particular, these are solid substrates such as glass, ceramics, metal, silicon wafers or plastic substrates, or flexible substrates, in particular plastic films or metal foils. The substrate to be coated may already have a structure of one or more, sometimes differently thick, layers. For example, in the case that the method according to the invention is used to produce layers for electronic components, the substrate to be coated may consist of the usual substructure for such components. For example, in the case of thin-film transistors (TFTs) or field-effect transistors (FETs) to be applied to a semiconducting metal oxide layer of a dielectric-coated conductive layer, the so-called "gate" on which metal electrodes ("source" and "Drain") are located.

The thickness of the functional structure produced according to the invention is preferably in the range between an atomic or molecular layer and 2 μm, particularly preferably between 10 nm and 500 nm. If required, thicker layers can also be produced, with a view to a high resolution of the structures produced or however, a uniform surface area of 2 μm or less has been found to be advantageous.

In a variant of the method, functional structures are produced, which are a metal oxide layer, wherein the metal oxide is preferably selected from the oxides or mixed oxides of the elements from the group of aluminum, magnesium, gallium, neodymium, ruthenium, hafnium, zirconium, indium, zinc, Titanium, yttrium, chromium, copper, iron, lithium and tin.

In another variant of the method, a functional structure produced is a metal layer, wherein the metal is preferably selected from the elements copper, silver and gold.

By "layer" is meant a smooth or structured layer, wherein structuring in the case of electronic components can also mean that as a "layer" z. B. only individual tracks are generated.

The precursor compounds used according to the invention are vaporizable or sublimable materials or materials whose decomposition products are vaporisable or sublimable. In the following, "sublimable" is also used as a generic term for "vaporizable or sublimable". The materials should be sublimable under normal atmosphere (p = 1 atm) or under any protective atmosphere at any pressure. The sublimation temperature is preferably in the range 50 ° C. <T _sub <600 ° C.

The material to be sublimated may be a single compound or a mixture of different compounds that meet the criteria and structural patterns listed above.

Preference compounds preferably to be used according to the invention are sublimable metal complexes, preferably selected from the group of acetylacetonates, β-dionates, alkoxides and alkylmetalates. Particularly preferred precursor compounds are acetylacetonates, tri- and hexafluoroacetylacetonates, such as preferably indium (III) acetylacetonate, zinc (II) acetylacetonate, hafnium (IV) acetylacetonate, zirconium (IV) acetylacetonate, gallium (III) acetylacetonate, indium (III) trifluoroacetylacetonate , Aluminum (III) acetylacetonate, zinc (II) hexafluoroacetylacetonate, zirconium (IV) trifluoroacetylacetonate, stannic bis (acetylacetonate) dichlorides, dionates, preferably tris (2,2,6,6-tetramethyl-3,5-heptanedionato ) gallium (III), tris (2,2,6,6-tetramethyl-3,5-heptanedionato) indium (III), bis (2,2,6,6-tetramethyl-3,5-heptanedionato) zinc (II ), Alkoxides, such as preferably methoxides, ethoxides, butoxides, propoxides, in particular aluminum ethoxide, aluminum isopropoxide, tin (IV) tert-butoxides, zinc methoxide, but also to name alkyl metalates, such as trimethylindium.

During the actual transfer process, the donor band is brought into close proximity or in direct contact with the substrate to be coated. By rapidly heating the donor ribbon, the precursor material is sublimed / vaporized or decomposed and the decomposition products are sublimated / vaporized and adsorbed on the substrate. The heating process can be initiated by any methods, in this case resistance heating elements are preferred. The size of the coated area on the substrate is determined primarily by the size of the area on the material carrier from which a sublimation takes place. This allows lateral structuring of the layer produced.

The basic structure of an apparatus for the coating method described above is described in 1 specified. In the figure ( 1 ) the input of the imaging signal, ( 2 ) the printhead, ( 3 ) the heating element, ( 4 ) the donor band, ( 5 ) the precursor material, ( 6 ) applied to the substrate material and ( 7 ) the substrate. An exemplary process variant is described below: Donor band ( 4 ) and substrate ( 7 ) can be carried out in webs on wheels. The donor ribbon ( 4 ) is unrolled from a roll and at a defined distance at the print head ( 2 ) and finally rolled up again. The distance printhead - donor band depends on which thermal source ( 3 ) in the print head ( 2 ) is used. When using thermal printheads with resistive heaters, the donor ribbon is passed directly over the printhead.

The distance of the donor ribbon to the substrate should be low in view of high print resolution. Preferably, the distance is in the range of 0.01 to 1 mm. For absorbent or porous substrates, the distance may also be 0, d. H. the transmission takes place in contact.

Accordingly, for a preferred variant of the method according to the invention that when evaporation or sublimation of the precursor compounds either contact between donor ribbon and substrate or the distance between the donor ribbon and substrate is preferably in the range of 0.01 and 1 mm, more preferably between 0.1 and 0.8 mm.

The web-shaped substrate ( 7 ) is under the print head ( 2 ) emotional. For register-accurate transmission of the precursor material ( 5 ) and to prevent defects, the speed of the donor ribbon and substrate can be controlled. Register marks can be applied on the substrate and / or on the donor band, which can be read out by register mark sensors and used for the regulation of donor belt and / or substrate. The donor belt as well as the substrate do not necessarily have to be moved continuously. Thus, for example, different materials may be applied to the donor belt in different sections or a substrate may be printed in multiple layers. Then the donor belt and / or the substrate must be moved discontinuously and / or asynchronously. Likewise, embodiments of the apparatus are possible in which only the printhead with the donor belt or only the substrate are moved to z. B. rigid sheet-shaped substrates to print.

The growth and morphology of the deposited layers (porosity, roughness, crystallinity) can be influenced on a given substrate by the sublimation temperature, the rate of sublimation and the temperature of the substrate to be printed. Again, since layer growth has a strong influence on the properties, particularly the electrical properties, the deposited layers and the corresponding interfaces, the sublimation temperature, sublimation rate and substrate temperature are important process parameters for the skilled person to control the properties of the deposited layers and interfaces , The optimization of these parameters is part of the routine of those skilled in such printing processes.

As a printhead commercially available thermal printing elements can be used, as they are also used in the thermal sublimation printing. The use of such a thermal print head is preferred in a variant of the invention.

The apparatus for carrying out the method according to the invention must be suitable for receiving the substrate, possibly transporting it and adjusting the distance between the donor belt and the substrate surface. In a variant of the invention, this may be commercial or modified thermal sublimation printers.

In a preferred process variant, the substrate can be aftertreated after deposition of the precursor compounds by introduction of energy. The methods used are conventional process steps, the optimization of which is familiar to the person skilled in the art. The post-treatment is preferably carried out by heating at a temperature in the range of 50 ° C to 700 ° C, preferably at 200 ° C to 500 ° C and / or by high-energy radiation, preferably from a high power light source or a laser. Additionally or alternatively, irradiation with UV and / or IR radiation can also take place. In the case of UV irradiation, wavelengths <400 nm, preferably in the range of 150 to 380 nm, are used. IR radiation can be used with wavelengths of> 800 nm be, preferably from> 800 to 3000 nm. By the aftertreatment, depending on the precursor compound used, they are chemically reacted and / or the surface of the structures are smoothed by melting or sintering operations. The electrical properties of metal oxides can also be partially improved by post-treatments. For example, the conductivity of indium tin oxide can be improved by storage or temperature treatment in a reducing atmosphere.

• – die Möglichkeit unlösliche Vorläufermaterialien einzusetzen,
• – die Vermeidung von Trägermaterialien wie Lösemittel und Wachse, sowie anderer Additive,
• – keine Benetzungsprobleme,
• – kein Anlösen bereits vorhandener Lagen durch Aufbringen weiteren Lösemittels,
• – keine Nachbehandlung zur Entfernung von Trägermaterial nötig,
• – Aufdampfen kann unter Umgebungsbedingungen erfolgen,
• – Vakuumtechnologie kann eingespart werden,
• – digitale Strukturierung ist möglich.
• – Der Beschichtungsvorgang kann bei Bedarf kontaktlos durchgeführt werden.

Advantages of this method according to the invention are:

• The possibility of using insoluble precursor materials,
• The avoidance of carrier materials such as solvents and waxes, as well as other additives,
• - no wetting problems,
• No dissolving of already existing layers by application of further solvent,
• - no post-treatment necessary to remove carrier material,
• - vapor deposition can take place under ambient conditions,
• - Vacuum technology can be saved
• - digital structuring is possible.
• - The coating process can be performed contactless if necessary.

The layers produced according to the invention can be determined by means of a scanning electron microscope, white light interferometer and X-ray photoelectron spectroscopy or by way of their application properties, such as eg. B. conductivity, resistance, impedance or scratch resistance characterize.

Further subjects of the invention are the use of the method according to the invention for producing a scratch-resistant surface coating and for the production of electrically semiconductive, conductive or insulating layers of electronic components, such as printed conductors, capacitors, insulating layers, transistors, in particular field effect transistors (FET) or thin-film transistors (TFT) and diodes. Corresponding electronic components obtainable by means of the method according to the invention are likewise the subject of the invention.

The following examples are intended to illustrate the present invention. However, they are by no means to be considered limiting. Any compounds or components that can be used in the formulations are either known and commercially available or can be synthesized by known methods.

Examples:

Example 1: Production of a semiconductive layer of zinc oxide

Example 1a Preparation of the Donor Tape

The material carrier consists of 50 μm thick polyimide film of the type "Upilex-S", purchased from UBE Europe. This is cut into 45 × 200 mm strips and cleaned with a clean room towel and isopropanol. Subsequently, the material carrier is coated in gravure with a solution of 5 wt .-% zinc acetylacetonate hydrate in 2-methoxyethanol. The printing parameters are 40 mm printing width, a printing force of 50 N and a printing speed of 0.5 m / s. The engraving parameters of the printing cylinder are 60 lines / cm with a scoop volume of 16 cm ³ / m ² . After printing, the layer of material dries on the substrate under ambient conditions.

Example 1b: Preparation of the ZnO layer

As a substrate, prefabricated substrates with a bottom-gate transistor structure are used. These consist of a conductive gate made of silicon, a thermally grown silicon dioxide layer of 90 nm thickness as a dielectric and a plurality of TFT (thin film transistor) channels prefabricated in a lithographic process, including source and drain contacts made of a gold / ITO (indium -Tin-oxides) double layer (thickness: 40 nm). These substrates are cleaned in an ultrasonic bath with subsequent exposure to acetone, water and isopropanol.

The deposition takes place with a thermal printing element of the type EPL1604T2 of the manufacturer Matsushita. In this case, material carrier and substrate are moved in a selected distance of 0.5 mm parallel and synchronously to each other in steps of 125 microns. The thermal printing element EPL1604T2 heats per step for 100 ms at a supply voltage of 7.2 V from the back of the material carrier. As a result, the zinc acetylacetonate sublimes from the material carrier and settles on the substrate.

The aftertreatment of the layer applied in the dye sublimation printing takes place in a drying chamber under an iron-doped mercury vapor lamp for 5 minutes at a distance of 6 cm and an intensity of 0.6 W / cm ² . The substrate is then baked in a glove box under argon atmosphere on a hotplate at 325 ° C. for 2 minutes to improve charge carrier mobility.

Example 1c: Characterization of the layer properties

The electrical transport measurement is carried out with the aid of an Agilent B 1500 A in a glovebox under argon atmosphere. The effective charge carrier mobility μ is determined from the transfer curve using the relation:

Where L is the channel length, W is the channel width of the transistor, C _OX is the capacitance of the dielectric, I _{D is} the drain current, and V _{G is} the gate voltage. The resulting effective charge carrier mobility of the transistors is 0.05 to 0.10 cm ² / Vs.

2 shows the breaking edge of the transistor component (SEM image). A section of the transistor channel with the 90 nm thick dielectric layer is visible, in the left half of the picture a part of a contact layer and over the entire surface the zinc oxide applied in the sublimation of the dye.

Example 2: Production of a semiconductive layer of indium zinc oxide

Example 2a: Preparation of the donor ribbon with 2 layers of

Precursors:

The material carrier consists of 25 μm thick polyimide film of the type "Kapton HN" from the manufacturer DuPont. This is cut into 45 × 200 mm strips and cleaned with a clean room towel and isopropanol. Subsequently, the material carrier is coated with a Filmziehrahmen whose gap height is 80 microns with the material in two steps. First, a layer of a solution of 2.3 wt .-% zinc acetylacetonate hydrate in 2-methoxyethanol is applied to the material carrier and dried under ambient conditions. Subsequently, a second layer of a solution of 3.5% by weight of indium tris (2,2,6,6-tetramethyl-3,5-heptanedionato) in 1,2-dimethoxyethane is applied to this first layer and dried under ambient conditions ,

Example 2b: Production of the IZO Layer

Substrates are used according to Example 1. The thermal sublimation pressure is carried out as in Example 1, but the heating time is 30 ms. The printing is done three times to obtain a thicker layer of material. The aftertreatment takes place after the last layer applied in the sublimation of the sublimation of ambient atmosphere for 4 min on a hotplate at 450.degree.

Example 2c: Characterization of the layer properties

The electrical transport measurement is carried out as in Example 1. The effective charge carrier mobility of the transistors is 0.010 to 0.015 cm ² / Vs.

The composition of the printed layer was examined by X-ray photoelectron spectroscopy. The original composition of the scavenged solutions should give a zinc to indium ratio of one to 1.5. Immediately after printing, without post-treatment of the layer, the ratio of zinc to indium is one to 0.4. After post-treatment of the printed layer at 450 ° C, the ratio of zinc to indium is one to 0.1.

Example 3: Production of a semiconducting layer of indium zinc oxide

Example 3a Preparation of the Donor Tape with Premixed Precursor Compounds

The material carrier consists of 25 μm thick polyimide film of the type "Kapton HN" from the manufacturer DuPont. This is cut into 45 × 200 mm strips and cleaned with a clean room towel and isopropanol. Subsequently, the material carrier is coated with a Filmziehrahmen whose gap height is 80 microns with a mixture of materials. This material mixture consists of three volumes of a solution of 2.3 wt .-% zinc acetylacetonate hydrate and two volumes of a solution of 3.5 wt .-% indium acetylacetonate, each dissolved in chloroform or 2-methoxyethanol. After application, the layer is dried under ambient conditions.

Example 3b: Preparation of the IZO layer

Substrates are used according to Example 1. The thermal sublimation printing is carried out with a thermal printing element of the type KEE-57-12GAN2-STA of the manufacturer Kyocera. In this case, material carrier and substrate are moved in a selected distance of 0.25 mm parallel and synchronously to each other in steps of 125 microns. The thermo-printing element KEE-57-12GAN2-STA heats per step for 25 ms at a supply voltage of 24 V from the back of the material carrier. Thereby, the precursor compound mixture sublimes from the material carrier and settles on the substrate. The aftertreatment of the layer applied in the dye sublimation printing takes place in an ambient atmosphere for 4 minutes on a hotplate at 450.degree.

Example 3c: Characterization of the layer properties

The electrical transport measurement is carried out as in Example 1. The effective charge carrier mobility of the transistors is 0.05 to 0.35 cm ² / Vs.

The composition of the printed layer was examined by X-ray photoelectron spectroscopy. The original composition of the scavenged solutions should give a zinc to indium ratio of two to three. Directly after printing, without after-treatment of the layer, as well as after the post-treatment of the printed layer at 450 ° C, the ratio of zinc to indium is two to three.

Example 4: Production of a Multilayer, Semiconducting Layer of Indium Zinc Oxide

The donor ribbon is prepared according to Example 3. Substrates are used according to Example 1. The thermal sublimation printing is carried out according to Example 3. The aftertreatment of the layer applied in the dye sublimation printing takes place in ambient atmosphere for 4 min on a hotplate at 450 ° C.

The process of the dye sublimation printing and the post-treatment are carried out three times to prepare a multi-layered semiconductor layer.

The electrical transport measurement is carried out as in Example 1. 3a shows the output characteristic of the transistor. The measured drain current I _{D is shown} across the drain voltage V _D for different applied gate voltages V _G of 0 V to 30 V. In this case, back and forth measurements were always carried out. There is no hysteresis. The characteristics saturate at increased V _D. I _D in saturation increases quadratically with the applied voltage, indicating a very good semiconductor behavior.

3b shows the transfer characteristic of the transistor. The measured drain current I _D over the gate voltage V _G for the applied drain voltages V _D of 5 V and 30 V can be seen. Back and forth measurements were always carried out. It can be seen only a very low hysteresis in the off state. The transistor turns on at V _G = 0 V, I _D rises steeply and then saturates at higher V. This indicates a very good semiconductor behavior. The effective charge carrier mobility determined from this characteristic is 7 cm ² / Vs, the threshold voltage 6.6 V and the ratio of I _D between on and off state is 2.6 × 10 ⁹ . The resulting effective charge carrier mobility of the transistors is 4 to 7 cm ² / Vs.

4 shows a photograph with a scanning electron microscope at a fracture edge of the transistor. A section of the transistor channel with the 90 nm-thick dielectric layer is visible, in the left half of the picture a part of a contact layer and over the entire surface the indium-zinc oxide applied in the sublimation of the dye.

Example 5: Production of conductive structures of indium tin oxide

Example 5a: Preparation of the donor ribbon

The material carrier consists of 25 μm thick polyimide film of the type "Kapton HN" from the manufacturer DuPont. This is cut into 45 × 200 mm strips and cleaned with a clean room towel and isopropanol. Subsequently, the material carrier is coated with a Filmziehrahmen whose gap height is 80 microns, with a mixture of materials. This material mixture consists of a mixture of 6.13% by weight of indium acetylacetonate and 2.93% by weight of tin (IV) bis (acetylacetonate) dichlorides, which were each dissolved in chloroform and then in a volume ratio of 4.42: 1 were mixed to adjust a molar ratio of indium: tin 90:10 of the mixture. After application, the layer is dried under ambient conditions.

Example 5b: Preparation of the ITO layer

The substrate used is silicon wafers with a thermally grown silicon dioxide layer of 90 nm thickness. These substrates are cleaned in an ultrasonic bath with subsequent exposure to acetone, water and isopropanol. Subsequently, platinum electrodes with a thickness of 40 nm are applied through a mask with the aid of a turbo sputter coater type 208 HR of the manufacturer Cressington. These are arranged in pairs at different distances.

The thermal sublimation printing is carried out according to Example 3, wherein the thermal printing element is heated per step for 20 ms. In the process, lines of 500 μm width are printed between the platinum electrodes.

The aftertreatment of the layer applied in the dye sublimation printing takes place in an ambient atmosphere for 4 minutes on a hotplate at 450.degree.

The process of sublimation printing and post-treatment are performed six times to produce a thick, low resistance wiring. Even after a process run, an electrical conductivity is already detectable.

Example 5c: Characterization of the layer properties

The characterization takes place under ambient conditions. In each case two electrodes of a pair are contacted by means of contact needles and the resistance between the electrodes is measured with the aid of an Agilent 3458A multimeter. From the conductor cross-section determined by means of a Sensofar Plμ Neox and the measured resistances, a specific resistance ρ of the material thus printed can be calculated, adjusted for the contact resistance.

Where:

Where R is the _{conductor of} the measured resistance, R is the _contact resistance, A is the _{conductor of} the cross section and L is the _conductor length.

5 shows the resistances of the ITO conductor track measured at different conductor lengths. The equalizer line shows that there is a resistance for the length "0". The contact resistance. In this way a specific resistance of 30 mΩcm was determined.

Subsequent annealing of the substrate in argon atmosphere and redetermination of the resistivity gives a value of 1.5 mΩcm.

This value surpasses the H. Tomonaga and T. Morimoto in Thin Solid Films 392 (2001) pp. 243-248 described, spin-coated ITO layer for which after heating the layer produced in argon, a specific resistance of 2 mΩcm is given.

In addition, in the example according to the invention, the conductor layer is applied in a structured manner in the sublimation of the sublimation, and subsequent structuring by, for example, etching is omitted.

6 shows a recording of the substrate surface of a substrate prepared according to Example 5. The image was taken with a white light interferometer. You can see ITO printed circuit boards and platinum contact pads at both ends of the tracks.

7 shows a photograph with a scanning electron microscope at a fracture edge of a substrate prepared according to Example 5. On view is a section of an ITO trace on the silicon wafer.

EXAMPLE 6 Production of a Condenser by Dye Sublimation Printing of Dielectric Layers of Hafnium Oxide

Example 6a: Preparation of the Donor Tape

The material carrier consists of 25 μm thick polyimide film of the type "Kapton HN" from the manufacturer DuPont. This is cut into 45 × 200 mm strips and cleaned with a clean room towel and isopropanol. Subsequently, the material carrier is coated with a Filmziehrahmen whose gap height is 80 microns, with a solution of 10 wt .-% hafnium acetylacetonate dissolved in chloroform. After application, the layer is dried under ambient conditions.

Example 6b: Preparation of hafnium oxide layer

The substrate used is alkali-free quartz glass. These substrates are cleaned in an ultrasonic bath with subsequent exposure to acetone, water and isopropanol. Subsequently, platinum electrodes with a thickness of 40 nm are applied through a mask with the aid of a turbo sputter coater type 208 HR of the manufacturer Cressington. These electrodes are 230 μm wide and 2 mm long. The thermal sublimation printing is carried out according to Example 3, wherein the thermal printing element is heated per step for 20 ms. In this case, rectangles of 1 × 1 mm ^{2 are} printed on the platinum electrodes. The aftertreatment of the layer applied in the dye sublimation printing takes place in an ambient atmosphere for 4 minutes on a hotplate at 450.degree.

The process of sublimation printing and post-treatment are carried out five times.

Example 6c: Preparation of the capacitor

Subsequently, a second platinum electrode of the same dimension is rotated by 90 ° applied over the first. Thereby, a capacitor of two platinum electrodes and an intermediate dielectric of hafnium oxide having an area of 230 × 230 microns ^{2 is} generated. 8th shows the schematic representation of the structure of a capacitor according to Example 6. On the quartz glass carrier are two printed circuit boards made of platinum and in between the layer of the dielectric hafnium oxide.

Example 6d: Characterization of the capacitor

The characterization takes place in a glovebox under argon atmosphere. Therein the substrates are stored for at least two days prior to characterization. Both electrodes are outside the capacitor area with the help of Contact needles contacted. Using a Solartron ModuLab Materials Test System, an impedance spectroscopy is performed and the capacitance of the capacitor is determined by the device software using an equivalent circuit of capacitor and parallel resistor. In addition, the thickness of the dielectric layer is measured with a Sensofar Plμ Neox. Finally, by means of the capacitor equation C = ε ₀ · ε _r · A / d the relative permittivity ε _{r of} the dielectric can be determined. The following applies: C is the capacitance of the capacitor, A the electrode surface, d their distance, ε ₀ the electric field constant in vacuum and ε _r the relative permittivity of the dielectric. The dielectric layers thus characterized showed a relative permittivity of 20.

In addition, electrical breakdown measurements were performed using an Agilent B 1500A. In this case, a short circuit of the two electrodes occurred only at voltages of 65 V.

9 shows the result of the impedance measurement of the capacitor. Shown are the frequency plotted against the amount of impedance and the phase shift. In addition, the fitting characteristics of an ideal capacitor are shown in an equivalent circuit diagram. This consists of a capacitor with a parallel resistor. The measured characteristics fit very well with the ideal, calculated characteristics from the fitting. The peak in the phase shift is 50 Hz and is caused by the line frequency.

10 shows a photograph with a scanning electron microscope at a fracture edge of a capacitor according to Example 6. Above and below the platinum electrodes and between them the hafnium oxide can be seen.

List of figures

1 shows the principle of the transfer process. In the figure ( 1 ) the input of the imaging signal, ( 2 ) the printhead, ( 3 ) the heating element, ( 4 ) the donor band, ( 5 ) the precursor material, ( 6 ) applied to the substrate material and ( 7 ) the substrate.

2 shows the fracture edge of a substrate prepared according to Example 1. On the picture taken with a scanning electron microscope, a region of the transistor channel with the 90 nm thick dielectric layer, in the left half of the image a part of a contact layer and over the entire surface the zinc oxide applied in the dye sublimation printing.

3a shows the output characteristic of a transistor according to Example 4. The measurement was carried out as described in Example 1. The measured drain current I _{D is shown} across the drain voltage V _D for different applied gate voltages V _G of 0 V to 30 V. In this case, back and forth measurements were always carried out. There is no hysteresis. The characteristics saturate at increased V _D. I _D in saturation increases quadratically with the applied voltage, indicating a very good semiconductor behavior.

3b shows the transfer characteristic of a transistor according to Example 4. The measurement was carried out as described in Example 1. The measured drain current I _D over the gate voltage V _G for the applied drain voltages V _D of 5 V and 30 V can be seen. Back and forth measurements were always carried out. It can be seen only a very low hysteresis in the off state. The transistor turns on at V _G = 0V, I _D rises steeply and then saturates at higher V _G. This indicates a very good semiconductor behavior. The effective charge carrier mobility determined from this characteristic is 7 cm ² / Vs, the threshold voltage 6.6 V and the ratio of I _D between on and off state is 2.6 × 10 ⁹ .

4 2 shows a region of the transistor channel with the 90 nm-thick dielectric layer, in the left-hand half a part of a contact layer and over the entire surface the indium-zinc applied in the dye sublimation printing -Oxide.

5 shows the measured at different conductor lengths resistances of the ITO trace according to Example 5. The balance line shows that for the length "0" a resistance exists. The contact resistance. In this way a specific resistance of 30 mΩcm was determined.

6 shows a recording of the substrate surface of a substrate prepared according to Example 5. The image was taken with a white light interferometer. You can see ITO printed circuit boards and platinum contact pads at both ends of the tracks.

7 shows a photograph with a scanning electron microscope at a fracture edge of a substrate prepared according to Example 5. On view is a section of an ITO trace on the silicon wafer.

8th shows the schematic representation of the structure of a capacitor according to Example 6. On the quartz glass carrier are two printed circuit boards made of platinum and in between the layer of the dielectric hafnium oxide.

9 shows the result of the impedance measurement of the capacitor according to Example 6. Shown are plotted over the frequency of the amount of impedance and the phase shift. In addition, the fitting characteristics of an ideal capacitor are shown in an equivalent circuit diagram. This consists of a capacitor with a parallel resistor. The measured characteristics fit very well with the ideal, calculated characteristics from the fitting. The peak in the phase shift is 50 Hz and is caused by the line frequency.

10 shows a photograph with a scanning electron microscope at a fracture edge of a capacitor according to Example 6. Above and below the platinum electrodes and between them the hafnium oxide can be seen.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• McCulloch; Chem. Mater. 17 (2005) 1381-1385 [0004]
• Bornemann; J. Imaging Sci. Technol. 55 (4): 040201-1-8, 2011 [0005]
• H. Tomonaga and T. Morimoto in Thin Solid Films 392 (2001) pp. 243-248 [0068]

Claims (17)

A method of producing functional structures by evaporating or sublimating precursor compounds from a donor ribbon and depositing on a substrate. A method according to claim 1, characterized in that in a first step, a donor band coated with precursor compounds is produced. Method according to one or more of claims 1 or 2, characterized in that as a carrier material for the donor ribbon, a film having a thickness in the range 0.1 .mu.m to 1 mm is selected, wherein a support material is used, which is up to 50 ° C above the Sublimation temperature of the material to be applied is chemically stable. Method according to one or more of claims 1 to 3, characterized in that as carrier material for the donor ribbon paper, thin glass, metal foil or a polymer film is selected, wherein the polymer film is preferably selected from polyethylene terephthalate-polyethylene-polypropylene or polyimide films. Method according to one or more of claims 1 to 4, characterized in that the substrate is post-treated by energy input after depositing the precursor compounds, wherein the post-treatment preferably by heating at a temperature in the range of 50 ° C to 700 ° C, preferably 200 ° C to 500 ° C or by means of high-energy radiation, preferably from a high-power light source or a laser takes place. Method according to one or more of claims 1 to 5, characterized in that the thickness of the functional structure is in each case in the range between an atomic or molecular layer and 2 microns, preferably between 10 nm and 500 nm. Method according to one or more of claims 1 to 6, characterized in that a solid substrate such as glass, ceramic, metal, silicon wafer or plastic substrate, or a flexible substrate, in particular a plastic film or a metal foil, is used as the substrate. Process according to one or more of Claims 1 to 7, characterized in that a functional structure produced is a metal oxide layer, the metal oxide preferably being selected from the oxides or mixed oxides of the elements from the group aluminum, magnesium, gallium, neodymium, Ruthenium, hafnium, zirconium, indium, zinc, titanium, yttrium, chromium, copper, iron, lithium and tin. Method according to one or more of Claims 1 to 8, characterized in that a functional structure produced is a metal layer, the metal preferably being selected from the elements copper, silver and gold. Method according to one or more of claims 1 to 9, characterized in that are used as precursor compounds sublimable metal complexes, preferably selected from the group of acetylacetonates, β-dionates, alkoxides and alkyl metalates. Method according to one or more of claims 1 to 10, characterized in that during evaporation or sublimation of the precursor compounds either contact between donor ribbon and substrate or the distance between donor ribbon and substrate is preferably in the range of 0.01 and 1 mm, particularly preferably between 0.1 and 0.8 mm. Method according to one or more of claims 1 to 11, characterized in that a thermal print head is used. Donor strip suitable for evaporation or sublimation processes, such as, for example, dye sublimation printing, characterized in that it comprises a carrier material to which precursor compounds have been applied. Donor band according to claim 13, characterized in that a foil having a thickness in the range of 0.1 μm to 1 mm is selected as carrier material for the donor ribbon, a carrier material being used which is chemically stable up to 50 ° C above the sublimation temperature of the material to be applied. Method according to one or more of claims 13 or 14, characterized in that as support material for the donor ribbon paper, thin glass, metal foil or a polymer film is selected, wherein the polymer film is preferably selected from polyethylene terephthalate-polyethylene-polypropylene or polyimide films. Use of the method according to one or more of claims 1 to 12 for the production of a scratch-resistant surface coating. Use of the method according to one or more of claims 1 to 12 for the production of electrically semiconductive, conductive or insulating layers of electronic components, such as printed conductors, capacitors, insulating layers, transistors, in particular field-effect transistors (FET) or thin-film transistors (TFT) and diodes.

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