EP2938760A1 - Substances de dopage liquides destinées au dopage local de tranches de silicium - Google Patents

Substances de dopage liquides destinées au dopage local de tranches de silicium

Info

Publication number
EP2938760A1
EP2938760A1 EP13817655.7A EP13817655A EP2938760A1 EP 2938760 A1 EP2938760 A1 EP 2938760A1 EP 13817655 A EP13817655 A EP 13817655A EP 2938760 A1 EP2938760 A1 EP 2938760A1
Authority
EP
European Patent Office
Prior art keywords
doping
silicon
oxide
media
diffusion
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.)
Withdrawn
Application number
EP13817655.7A
Other languages
German (de)
English (en)
Inventor
Ingo Koehler
Oliver Doll
Sebastian Barth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Merck Patent GmbH
Original Assignee
Merck Patent GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Merck Patent GmbH filed Critical Merck Patent GmbH
Priority to EP13817655.7A priority Critical patent/EP2938760A1/fr
Publication of EP2938760A1 publication Critical patent/EP2938760A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B31/00—Diffusion or doping processes for single crystals or homogeneous polycrystalline material with defined structure; Apparatus therefor
    • C30B31/04—Diffusion or doping processes for single crystals or homogeneous polycrystalline material with defined structure; Apparatus therefor by contacting with diffusion materials in the liquid state
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
    • H01L29/167—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table further characterised by the doping material
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D1/00—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C30B29/06—Silicon
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B31/00—Diffusion or doping processes for single crystals or homogeneous polycrystalline material with defined structure; Apparatus therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/22—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities
    • H01L21/225—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities using diffusion into or out of a solid from or into a solid phase, e.g. a doped oxide layer
    • H01L21/2251—Diffusion into or out of group IV semiconductors
    • H01L21/2254—Diffusion into or out of group IV semiconductors from or through or into an applied layer, e.g. photoresist, nitrides
    • H01L21/2255—Diffusion into or out of group IV semiconductors from or through or into an applied layer, e.g. photoresist, nitrides the applied layer comprising oxides only, e.g. P2O5, PSG, H3BO3, doped oxides
    • H01L21/2256—Diffusion into or out of group IV semiconductors from or through or into an applied layer, e.g. photoresist, nitrides the applied layer comprising oxides only, e.g. P2O5, PSG, H3BO3, doped oxides through the applied layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/324—Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
    • H01L31/068—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
    • H01L31/068—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • H01L31/0682—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells back-junction, i.e. rearside emitter, solar cells, e.g. interdigitated base-emitter regions back-junction cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic Table
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/547—Monocrystalline silicon PV cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a novel process for the preparation of printable, low viscosity oxide media, and their use in solar cell manufacturing, as well as the improved lifetime products produced using these novel media.
  • a silicon wafer (monocrystalline, multicrystalline or quasi-monocrystalline, p- or n-type base doping) is freed of adherent saw damage by means of an etching process and "simultaneously", usually in the same etching bath, texturized in this case, the creation of a preferred Surface (texture) as a result of the etching step or simply to understand the targeted, but not particularly oriented roughening of the wafer surface
  • the aforementioned etching solutions for treating the silicon wafers typically consist of dilute potassium hydroxide solution to which isopropyl alcohol has been added as solvent. Instead, other alcohols having a higher vapor pressure or higher boiling point than isopropyl alcohol may be added, provided that the desired etching result can be achieved thereby.
  • the desired etch result is a morphology that is randomly-etched, or rather etched out of the original surface.
  • Pyramids is characterized by square base. The density, the height and thus the base area of the pyramids can be influenced by a suitable choice of the above-mentioned constituents of the etching solution, the etching temperature and the residence time of the wafers in the etching basin.
  • Temperature range of 70 - ⁇ 90 ° C performed, with ⁇ tzabträge of up to 10 pm per wafer side can be achieved.
  • the etching solution may consist of potassium hydroxide solution with an average concentration (10-15%).
  • this etching technique is hardly used in industrial practice. More often becomes one
  • Etching solution consisting of nitric acid, hydrofluoric acid and water used.
  • This etching solution can be modified by various additives such as sulfuric acid, phosphoric acid, acetic acid, N-methylpyrrolidone and also surfactants, which u. a.
  • Wetting properties of the etching solution and their etch rate can be specifically influenced.
  • These acid etch mixtures produce a morphology of interstitially arranged etch pits on the surface.
  • the etching is typically carried out at temperatures in the range between 4 ° C to ⁇ 10 ° C and the ⁇ tzabtrag here is usually 4 pm to 6 pm.
  • the wafers are placed in a tube furnace in a quartz glass tube of a controlled atmosphere consisting of dried nitrogen, dried oxygen and phosphoryl chloride.
  • the wafers are introduced at temperatures between 600 and 700 ° C in the quartz glass tube.
  • the gas mixture is transported through the quartz glass tube.
  • the phosphoryl chloride decomposes into a vapor consisting of phosphorus oxide (eg P2O5) and chlorine gas.
  • the vapor of phosphorus oxide is deposited among other things on the wafer surfaces (occupancy).
  • the silicon surface is oxidized at these temperatures to form a thin oxide layer. In this layer, the deposited phosphorus oxide is embedded, whereby a mixed oxide of silicon dioxide and phosphorus oxide formed on the wafer surface.
  • This mixed oxide is called phosphosilicate glass (PSG).
  • PSG phosphosilicate glass
  • the mixed oxide serves the silicon wafer as a diffusion source, wherein in the course of the diffusion, the phosphorus oxide diffuses in the direction of the interface between PSG glass and silicon wafer and is reduced there by reaction with the silicon on the wafer surface (silicothermally) to phosphorus.
  • the resulting phosphor has a solubility which is orders of magnitude greater in silicon than in the glass matrix from which it is formed, and thus dissolves preferentially in silicon due to the very high segregation coefficient.
  • the phosphorus in silicon diffuses along the concentration gradient into the volume of silicon. In this diffusion process, concentration gradients of the order of 105 between typical
  • a PSG layer is formed, which typically has a layer thickness of 40 to 60 nm. in the
  • the composition of the gas mixture is adjusted so that the further supply of phosphoryl chloride is suppressed.
  • the surface of the silicon is further oxidized by the oxygen contained in the gas mixture, whereby a phosphorus depleted silicon dioxide layer is also generated between the actual doping source, the phosphorus oxide highly enriched PSG glass and the silicon wafer
  • the tube furnace is automatically cooled and the wafers can be removed from the process tube at temperatures between 600 ° C to 700 ° C.
  • Composition of the gas atmosphere used for doping the formation of a so-called boron skin can be detected on the wafers.
  • This boron skin is dependent on various influencing factors: decisive for the doping atmosphere, the temperature, the doping time, the
  • Pretreatment were subjected (for example, their structuring with diffusion-inhibiting and / or -unterbindenden layers and
  • Doping sources for example, dilute solutions of phosphoric or boric acid, as well as sol-gel-based systems or solutions of polymeric Borazilitatien can be used.
  • additional thickening polymers characterized, and contain dopants in a suitable form.
  • dopants in a suitable form.
  • evaporation of Solvents from the aforementioned doping media are usually followed by a high-temperature treatment during which undesirable and interfering additives which cause the formulation are either "burned" and / or pyrolyzed., The removal of solvents and the burn-out may or may not , take place simultaneously.
  • the coated substrates usually pass through a continuous furnace at temperatures between 800 ° C and 1000 ° C, to shorten the cycle time, the temperatures in comparison to
  • Gas phase diffusion in the tube furnace can be slightly increased.
  • the prevailing in the continuous furnace gas atmosphere can according to the
  • Nitrogen dry air, a mixture of dry oxygen and dry nitrogen and / or, depending on the design of the furnace to be passed, zones of one and the other of the above
  • Driving the dopant can in principle be decoupled from each other.
  • the wafers present after the doping are coated on both sides with more or less glass on both sides of the surface. More or less in this case refers to modifications that can be applied in the context of the doping process: double-sided diffusion vs. quasi one-sided diffusion mediated by back-to-back arrangement of two wafers in a parking space of the process boats used. The latter
  • Variant allows a predominantly one-sided doping, but does not completely prevent the diffusion on the back.
  • the wafers are on the one hand transhipped in batches in wet process boats and with their help in a solution of dilute hydrofluoric acid, typically 2% to 5%, immersed and left in this until either the surface is completely removed from the glasses, or Process cycle has expired, which represents a sum parameter of the necessary ⁇ tzdauer and the automatic process automation.
  • the complete removal of the glasses can be determined, for example, by the complete dewetting of the silicon wafer surface by the dilute aqueous hydrofluoric acid solution.
  • the etching of the glasses on the wafer surfaces can also be carried out in a horizontally operating method in which the wafers are introduced in a constant flow into an etching system in which the wafers pass through the corresponding process tanks horizontally (inline system).
  • the wafers are conveyed on rollers and rollers either through the process tanks and the etching solutions contained therein or the etching media are transported onto the wafer surfaces by means of roller application.
  • the typical residence time of the wafers in the case of etching the PSG glass is about 90 seconds, and the hydrofluoric acid used is somewhat more concentrated than in the batch process
  • the concentration of hydrofluoric acid is typically 5%.
  • the tank temperature compared to the
  • edge insulation -> glass etching is a process engineering necessity, which results from the system-inherent characteristics of the double-sided diffusion, even with intentional unilateral back-to-back diffusion.
  • parasitic pn junction On the (later) back side of the solar cell there is a large-area parasitic pn junction which, although due to process technology, is partly, but not completely, removed in the course of the later processing. As a result, the Front and back of the solar cell via a parasitic and
  • the wafers are unilaterally via an etching solution
  • the etching solution may contain as minor constituents, for example, sulfuric acid or phosphoric acid.
  • the etching solution is transported via rollers mediated on the back of the wafer.
  • the etching erosion typically achieved with these methods amounts to approximately 1 ⁇ m silicon at temperatures between 4 ° C. to 8 ° C. (including the glass layer present on the surface to be treated). In this method, the glass layer remaining on the opposite side of the wafer serves as a mask before
  • edge isolation can also be done with the help of
  • Plasma etching processes are performed. This plasma etching is then usually carried out before the glass etching. For this purpose, several wafers are stacked on each other and the outer edges become the plasma
  • the plasma is filled with fluorinated gases, for example
  • Tetrafluoromethane fed.
  • Solar cells with an anti-reflection coating which usually consists of amorphous and hydrogen-rich silicon nitride.
  • Antireflection coatings are conceivable. Possible coatings may include titanium dioxide, magnesium fluoride, tin dioxide and / or
  • the layer generates an electric field due to the numerous incorporated positive charges that charge carriers in the silicon can keep away from the surface and the recombination of these charge carriers at the
  • this layer depending on its optical parameters, such as refractive index and layer thickness, this layer generates a reflection-reducing property which contributes to the fact that more light can be coupled into the later solar cell. Both effects can increase the conversion efficiency of the solar cell.
  • the antireflection reduction is most pronounced in the wavelength range of the light of 600 nm.
  • the directional and non-directional reflection shows a value of about 1% to 3% of the originally incident light (perpendicular incidence to the surface normal of the silicon wafer).
  • the above-mentioned silicon nitride films are currently deposited on the surface generally by direct PECVD method.
  • a gas atmosphere of argon is ignited a plasma, in which silane and ammonia are introduced.
  • the silane and the ammonia are converted in the plasma by ionic and radical reactions to silicon nitride and thereby deposited on the wafer surface.
  • the properties of the layers can z. B. adjusted and controlled by the individual gas flows of the reactants.
  • the deposition of the above-mentioned silicon nitride layers can also be carried out using hydrogen as the carrier gas and / or the reactants alone. Typical deposition temperatures are in the range between 300 ° C to 400 ° C.
  • Alternative deposition methods may be, for example, LPCVD and / or sputtering. 5th generation of front electrode electrode
  • Silicon nitride coated wafer surface defines the front electrode.
  • the electrode has been established using the screen printing method using metallic
  • the sum of the residual constituents results from the rheological aids necessary for formulating the paste, such as, for example, solvents, binders and thickeners.
  • the silver paste contains a special Glasfrit mixture, mostly oxides and mixed oxides based on
  • the glass frit fulfills essentially two functions: on the one hand it serves as a bonding agent between the wafer surface and the mass of the silver particles to be sintered, on the other hand it is responsible for the penetration of the silicon nitride covering layer in order to enable the direct ohmic contact to the underlying silicon.
  • the penetration of the silicon nitride takes place via an etching process with subsequent diffusion of silver present dissolved in the glass frit matrix into the silicon surface, whereby the ohmic contact formation is achieved.
  • the silver paste is deposited by screen printing on the wafer surface and then dried at temperatures of about 200 ° C to 300 ° C for a few minutes. For the sake of completeness, it should be mentioned that double-printing processes also find industrial application, which make it possible to print on an electrode grid generated during the first printing step, a congruent second.
  • the solvents contained in the paste are expelled from the paste.
  • the printed wafer passes through a continuous furnace.
  • Such an oven generally has several heating zones, which can be independently controlled and tempered.
  • the wafers are heated to temperatures up to about 950 ° C.
  • the single wafer is typically exposed to this peak temperature for only a few seconds.
  • the wafer has temperatures of 600 ° C to 800 ° C. In these
  • Temperatures are contained in the silver paste contained organic impurities such as binder, and the etching of the silver paste.
  • Silicon nitride layer is initiated. During the short time interval of the prevailing peak temperatures, contact formation occurs.
  • the front electrode grid consists of thin fingers
  • the rear bus buses are also usually by means of
  • the back electrode is defined following the pressure of the bus buses.
  • the electrode material is made of aluminum, therefore, to define the electrode, an aluminum-containing paste by screen printing on the remaining free area of the wafer back with a
  • Edge distance ⁇ 1 mm is printed.
  • the remaining components are those already mentioned under point 5 (such as solvents, binders, etc.).
  • the aluminum paste is bonded to the wafer during co-firing by causing the aluminum particles to start to melt during heating and remove silicon from the wafer in the wafer
  • melt mixture acts as a dopant source and releases aluminum to the silicon (solubility limit:
  • This potential wall is generally referred to as the back surface field or back surface field.
  • edge isolation of the wafer has not already been carried out as described under point 3, this is typically carried out after co-firing with the aid of laser beam methods.
  • a laser beam is directed to the front of the solar cell and the front p-n junction is severed by means of the energy coupled in by this beam.
  • This trench with a depth of up to 5 pm due to
  • this laser trench is 30 pm to 60 pm wide and about 200 pm away from the edge of the solar cell.
  • solar cell architectures with both n-type and p-type base material. These solar cell types include PERT solar cells
  • structured diffusion barriers may be deposited on the silicon wafers prior to depositing the glasses to define the regions to be doped.
  • a disadvantage of this method is that in each case only one polarity (n or p) of
  • Doping can be achieved. Somewhat simpler than the structuring of the doping sources or that of any diffusion barriers is the direct laser-beam driven driving-in of dopants from previously onto the
  • Wafer surfaces deposited dopant sources This method makes it possible to save costly structuring steps. Nevertheless, it can not compensate for the disadvantage of a possible simultaneous simultaneous doping of two polarities on the same surface at the same time (co-diffusion), since this method is likewise based on a predeposition of a dopant source, which is activated only subsequently for the emission of the dopant. Disadvantage of this (post-) doping from such sources is the inevitable laser damage to the substrate: the laser beam must by absorbing the radiation into heat
  • Dotiermedien (doping inks) are produced.
  • Alkoxysilanes or alkoxyalkylsilanes which may contain individual or various saturated, unsaturated, branched, unbranched aliphatic, alicyclic and aromatic radicals, which in turn may be attached at any position of the alkoxide radical by heteroatoms selected from the group O, N, may be used to carry out the process according to the invention.
  • S, Cl, Br can be functionalized.
  • the alkoxysilanes of the invention are N-(2-aminoethoxysilanes of the invention.
  • the alkoxysilanes used according to the invention can have saturated, unsaturated, branched, unbranched aliphatic, alicyclic and aromatic radicals individually or different of these radicals, which in turn can be attached to any position of the alkoxide radical by heteroatoms selected from the group O, N, S, Cl , Br can be functionalized.
  • hydrolyzable radicals are halogen (F, Cl, Br or I, preferably Cl and Br), alkoxy (especially C 1 alkoxy, such as
  • Particularly preferred hydrolysable radicals are alkoxy groups, in particular methoxy and ethoxy.
  • non-hydrolyzable radicals R 1 in the context of the invention are alkyl, in particular C 1-4 -alkyl (such as, for example, methyl, ethyl, propyl and butyl), alkenyl (in particular C 2 -alkenyl, for example vinyl, -propenyl, 2-propenyl and butenyl), alkynyl (especially C 2- 4-AIkinyl such as acetylenyl and propargyl), and aryl, in particular C 6 -aryl, for example phenyl and naphthyl), wherein the groups just mentioned, optionally one or more Substituents, such as halogen and alkoxy, may have.
  • alkyl in particular C 1-4 -alkyl (such as, for example, methyl, ethyl, propyl and butyl)
  • alkenyl in particular C 2 -alkenyl, for example vinyl, -propenyl, 2-propeny
  • alkoxysilanes used in the sol-gel reaction can form a three-dimensional network, which can form a thin layer during drying and compression, which is convertible by thermal treatment in a dense glass layer.
  • Alkoxysilanes are therefore preferably used in the invention, the low-boiling radicals
  • the radicals are preferably methoxy, ethoxy, n-propoxy, i-propoxy and butoxy, most preferably methoxy and ethoxy. Particular preference is therefore given to the alkoxysilanes
  • Tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS) worked.
  • alkoxyalkylsilanes in which one or two of the radicals have the meaning of alkyl, in particular C 1-4 -alkyl, such as e.g. Methyl, ethyl, propyl or butyl.
  • Reaction mixture a solvent or a solvent mixture are added in an appropriate amount, so that the reaction can be carried out in sufficient speed.
  • Suitable solvents for this purpose are those which are also formed by the condensation reaction itself, for example methanol, ethanol, propanol, butanol or other alcohols. Since protic solvents also lead to the termination of the condensation reaction, they can only be added in limited amounts. Aprotic, polar solvents, such as tetrahydrofuran, are therefore preferable.
  • Suitable inert solvents other than tetrahydrofuran are other sufficiently polar and non-protic solubilizers, for example 1,4-dioxane and dibenzyl ether, into consideration, it being possible to use further solvents having corresponding properties for this purpose.
  • By a suitable choice of the synthesis conditions it is possible to adjust the viscosity of the doping ink between a few mPas, for example 3 mPas, and 100 mPas.
  • Condensation reaction can be achieved by adding a sufficient amount of a protic solvent upon reaching a desired viscosity.
  • a protic solvent may include, for example, branched and unbranched, aliphatic, cyclic, saturated and unsaturated and aromatic mono-, di-, tri- and polyols, d.
  • protic solvents may be combined with any desired polar and non-polar aprotic solvents.
  • Solvent is not explicitly limited to substances that are added to
  • Tetramethylolpropane 2, 2-dimethyl-1, 3-pentanediol, tetradecanol or the like.
  • Compounds used are those selected from the group boron oxide, boric acid and boric acid esters.
  • phosphorus-containing compounds can be obtained oxide media with good properties, when the phosphorus-containing compounds are selected from the group of phosphorus (V) oxide, phosphoric acid, polyphosphoric acid, phosphoric acid esters and phosphonic acid esters with alpha and beta-functional siloxane-functionalized groups.
  • the printable oxide media in the form of doping media based on hybrid sols and or gels using alcoholates / esters, hydroxides or oxides of aluminum, gallium, germanium, zinc, tin, titanium, zirconium, or Lead, as well as their mixtures, so that a "hybrid" sol or gel is obtained using these components.
  • hybrid sols can be made sterically by addition of suitable masking agents, complexing agents and chelating agents in a sub stoichiometric ratio stabilize and on the other hand in terms of their
  • WO2012119685 A1 and WO20121 9684 A are known. The content of these publications is therefore included in the disclosure of the present application.
  • the oxide medium is up to a highly viscous, (nearly) glassy mass and the resulting product is brought back into solution, either by addition of a suitable solvent or solvent mixture.
  • a suitable solvent or solvent mixture for this protic and / or polar solvents are suitable, such as propanol, isopropanol, butanol, butyl acetate, or ethyl acetate u. a. Ethyl acetate, ethylene glycol monobutyl ether,
  • a stable mixture is prepared by the process according to the invention, which is storage stable for a period of at least three months.
  • the doping media produced by the process according to the invention are storage-stable, can be prepared reproducibly and are characterized by a constant, ie independent of the storage life, Doping power off. Furthermore, such media can be modified by the targeted addition of monofunctional or monoreactive (capping agent) siloxanes, so that the storage stability of the
  • Suitable monofunctional siloxanes for this purpose include: acetoxytrialkylsilanes, alkoxytrialkylsilanes, such as ethoxytrimethylsilane, halo-trialkylsilanes and their derivatives, and comparable compounds. That is, when "capping agents" are added to the oxide media during manufacture, this results in a further improvement in the stability of the resulting oxide media, making them particularly well suited for use as doped inks
  • the oxide media produced according to the invention may vary depending on the consistency, i. H. depending on their theological properties, such as, for example, their viscosity, by spin coating or dip coating, drop casting, curtain or slot dye coating, screen printing or flexoprinting, gravure, ink jet or aerosol jet printing, offset printing, Micro Contact Printing, Electrohydrodynamic
  • Glass layers are used, which act as a sodium and potassium diffusion barrier in the LCD technique as a result of thermal treatment, but in particular for the production of thin, dense glass layers on the cover glass of a display consisting of doped SiO 2 , the diffusion of ions from the Prevent coverslip into the liquid crystalline phase.
  • the present invention accordingly relates to the new, according to the invention
  • Oxidmedien which have been prepared according to the method described above and which binary or ternary systems from the group S1O2-P2O5, S1O2-B2O3, SiO 2 -P 2 O 5 - B2O3 and S1O2-Al2O3-B2O3 and / or mixtures of higher degree, which result from the use of alcoholates / esters, hydroxides or oxides of aluminum, gallium, germanium, zinc, tin, titanium, zirconium or lead during manufacture.
  • these hybrid sols can be obtained by addition of suitable
  • Masking agents, complex and chelating in a sub stoichiometric to a stoichiometric ratio on the one hand sterically stabilize and on the other hand in terms of their condensation and gelation rate but also in terms of the theological properties specifically influence and control. Suitable masking and complexing agents, as well
  • Chelating agents are known to those skilled in the patent applications WO 2012/119686 A, WO2012119685 A1 and WO2012119684 A.
  • the surface-printed oxide medium which is prepared by a method in the context of the invention, in a temperature range between 50 ° C and 750 ° C, preferably between 50 ° C and 500 ° C, more preferably between 50 ° C. and 400 ° C, using one or more, to be carried out sequentially Temper Colouren (tempering by means of a step function) and / or an annealing ramp, dried and compacted to the glazing, whereby a grip and abrasion resistant layer is formed with a thickness of up to 500 nm.
  • the heat treatment of the glazed on the surfaces layers at a temperature in the range between 750 ° C and 1100 ° C, preferably between 850 ° C and 1100 ° C, more preferably between 850 ° C and 000 ° C.
  • silicon-doping atoms such as boron and / or phosphorus
  • silicothermal reduction of the respective oxides on the substrate surface to the substrate itself deliver, whereby the conductivity of the silicon substrate is favorably favored favorable. It is particularly advantageous that due to the heat treatment of the printed substrate, the dopants depending on the
  • the surface concentrations of the dopant can usually assume values of greater than or equal to 1 ⁇ 10 19 to 1 ⁇ 10 21 atoms / cm 3 . This depends on the nature of the dopant used in the printable oxide medium.
  • Oxide media were covered by at least two powers of ten
  • hydrophilic means
  • hydrophobic in this context means: surfaces provided with silane termination, which does not exclude thin silicon layers on the surface
  • Silicon substrate to use and such silicon wafers with the
  • the effective dose of doping in the silicon substrate is thus affected by the temperature during the treatment and its duration, as well as indirectly by the diffusivity of the dopant in the thin oxide layer, but also by the temperature dependent segregation coefficients of the dopant between the silicon of the substrate and the
  • Silicon dioxide layer In general, the process according to the invention for the production of grip- and abrasion-resistant layers on silicon and silicon wafers can be characterized in that
  • Silicon wafers are printed with the oxide media as n-type dopant (for example, by ink jet printing), the printed Dotiermedien dried, compacted and then exposed to a subsequent gas phase diffusion with phosphoryl chloride, whereby high dopants are obtained in the printed areas and lower doping in the Be achieved areas that are exposed exclusively to the gas phase diffusion, or
  • Silicon wafers are printed with the oxide media as a p-type oxide medium, in this case with boron-containing precursors, the printed on doping dried, compacted and then exposed to a subsequent gas phase diffusion with boron trichloride or boron tribromide, whereby high doping is obtained in the printed areas and a lower doping is achieved in the areas which are exposed exclusively to the gas phase diffusion or
  • Doping medium is dried and / or compressed and from the compacted doped oxide medium by means of
  • Doping medium is dried and compacted and from the
  • compressed doping oxide medium is initiated by means of a suitable heat treatment, the doping of the underlying substrate, and subsequent to this doping process with subsequent local laser irradiation, the local doping of the underlying substrate material amplified and the dopant is driven deeper into the volume of the substrate
  • the silicon wafer is printed either over the whole area or locally with oxide media as doping media, which may be n- and p-doping media, optionally through
  • alternating structures which are dried and densified on printed structures and coated with suitable diffusion barrier materials, such as sol-gel based silica layers, sputtered or APCVD or PECVD based silicon dioxide, silicon nitride or silicon dioxide
  • Siliconoxynitrid für encapsulated and the doping acting oxide media are brought by suitable heat treatment for doping of the substrate,
  • the silicon wafer is printed either over the whole area or locally with oxide media as doping media, which may be n- and p-doping media. This may optionally have an alternating sequence of structures, such as printed n-doping oxide medium with any
  • Structure width for example, line width, adjacent to non-printed silicon surface, which also any combination thereof
  • the printed structures are dried and compacted, and subsequently the wafer surface can be provided with a doping medium of oppositely inducing majority charge carrier polarity over the entire surface or selectively printed on the already printed surface.
  • the last-mentioned doping media can be printable sol-gel-based oxidic doping materials, other printable doping inks and / or pastes, APCVD and / or PECVD glasses doped with dopants and dopants from conventional gas phase diffusion and doping.
  • doping oxide medium acts as a diffusion barrier to the one above it, and behaves as the majority majority carrier polarity-inducing dopant medium; Moreover, the opposite side of the
  • Wafer surface may be covered with a different and otherwise deposited (printed, CVD, PVD) diffusion barrier, such as a silicon dioxide, silicon nitride or
  • the silicon wafer is printed either over the whole area or locally with oxide media as doping media, which may be n- and p-doping media, optionally in alternating sequence, such as printed n-doping
  • any structure width for example, any line width, adjacent to non-printed Silicon surface, which also has any structural width.
  • the printed structures are dried and compacted, after which the wafer surface can be provided over the entire area with a doping medium with opposite inducing majority charge carrier polarity on the already printed wafer surface, and wherein the latter doping media can be printable sol-gel based oxidic dopants or other printable dopant inks and / or or pastes, doped APCVD and / or PECVD glasses, but also dopants from conventional gas phase diffusion and doping.
  • the overlapping arranged and doping acting doping media are brought by suitable heat treatment for doping of the substrate. In this case, the respectively underside, printed, doping oxide medium is due to appropriate
  • the opposite wafer surface can be covered by means of a different and otherwise deposited dopant source (printable sol-gel-based oxidic dopants, other printable
  • Oxide media their drying, and compaction and / or doping
  • thermal treatment resulting glass layers with a
  • the etchant used in this case contains as etchant hydrofluoric acid in a concentration of 0.001 to 10 wt .-% or 0.001 to 10 wt .-% hydrofluoric acid and 0.001 to 10 wt .-% phosphoric acid in the mixture.
  • the dried and compacted doping glasses can furthermore be removed from the wafer surface with other etching mixtures:
  • buffered hydrofluoric acid mixtures BHF
  • buffered oxide etch mixtures etching mixtures consisting of hydrofluoric and nitric acid, such as the so-called p-type etching, R-etching, S-etching, or etching mixtures, consisting of hydrofluoric acid and sulfuric acid, the aforementioned list not the Claim to completeness.
  • Inline diffusion is in principle the most efficient variant of doping silicon wafers, taking into account the industrial mass production of components that are manufactured under considerable cost pressure from two directions in billions of units. The cost pressure results both from a very pronounced political and market competitive situation. Inline diffusion can achieve industrial throughput rates that are typically between 15 to 25% higher than the usual
  • the dopant sources are applied to the wafers wet by means of suitable coating methods (spraying, rolling, screen printing, etc.), thermally dried, compacted and brought into the furnace system for diffusion.
  • suitable coating methods spraying, rolling, screen printing, etc.
  • Typical and commonly used sources of dopants are dilute ones
  • alcoholic in ethanol or isopropanol
  • aqueous solutions of phosphoric or boric acid should lead to a homogeneous film on the silicon surfaces, so that a uniform delivery of the dopant to the silicon is possible.
  • Phosphoric and boric acids have an increasing oxidic character upon drying of the solution and thermal transformation to polymeric species. The oxides in question are volatile and therefore can very easily contribute to auto-doping of regions of the substrate that were not initially homogeneously covered with the dopant source.
  • the structuring also relates to the creation of differently doped regions in a basically arbitrary, but often alternating, sequence in which either high and low-doped regions of a polarity (n- or p-type) or doped regions of alternating polarities (n - on p-type and vice versa) alternate.
  • n- or p-type polarity
  • doped regions of alternating polarities n - on p-type and vice versa
  • Wafer surface can be deposited
  • the printable dopant sources offer the potential to allow sufficient surface concentrations of dopants for the subsequent ohmic contacting of the doped regions
  • the printable dopant sources must be able to be driven into the treated silicon wafer in a co-diffusion step and thus simultaneously
  • Minority carrier lifetime is an essential basic parameter that decides on the conversion efficiency of a solar cell: low lifetime equal low efficiency and vice versa. Therefore, for the expert speaks against the use of the previously known printable doping media. The adverse effect on carrier lifetime is evident by the raw materials used to make the dopant media
  • auxiliaries necessary for the paste formulation, and in particular the polymeric binders are a source of contamination which is difficult to control and which has a negative effect on the performance of the silicon.
  • These adjuvants may contain unwanted, harmful metals and metal ions whose concentration is typically in the per mil range.
  • silicon reacts very sensitively to metallic contaminations already in the range of ppb to a few ppm - especially when the
  • Silicon treatment follows a high-temperature phase, which allows for the most effective distribution of these harmful contaminants in the bulk (via diffusion and "doping") of silicon. Such diffusions in wafers typically occur as a result of
  • Typical and particularly harmful contaminants are, for example, iron, copper, titanium, nickel and other transition metals from this group of
  • volume can penetrate than the desired dopants themselves, and thus can affect not only the surface of the silicon, but also its entire volume. So in case of iron, with the
  • binders added in the formulation of pastes are generally very difficult to even chemically clean up or free of their cargo of metallic trace elements. The effort to clean them is high and is due to the high cost in any
  • auxiliaries are a constant source of contamination, are favored by the unwanted contamination in the form of metallic species greatly.
  • Liquid phase dopant deposited on the silicon wafer surface In the subsequent drying of the liquid dopant, the metal ions contained in the ink are enriched in the remaining residue.
  • the enrichment factor is of the concentration in the liquid
  • the enrichment factor can be between 10 and 100. That is, with a metal ion load of 10 ppbw of any element, 100 ppbw to 1 ppmw in the dried
  • the layer containing the dopant thus represents a comparatively highly concentrated source of possible metal ions for the silicon substrate underneath.
  • the release of the metal ions from this layer is strongly dependent on the temperature and the
  • Material properties such as the segregation coefficient of the dopant layer over the silicon wafer dependent.
  • thermal activation of the dopant layer in order to allow the dopant to diffuse in silicon, can also considerably mobilize the metal ions.
  • diffusivity of most metal ions is many orders of magnitude higher than that of all dopants.
  • Metal ions (3d subgroup elements) diffused into the silicon although they can form silicides and partially precipitate as such, behave and / or precipitate on oxides and oxygen clusters and grain boundaries and dislocations, in some cases also very strongly. by electronically inducing deep impurities in the silicon. These depths
  • Impurities have a pronounced recombination activity for the minority carriers.
  • Minority carrier lifetime or diffusion length is one of the basic quality parameters of the silicon used for solar cell fabrication, it significantly determines the maximum conversion efficiency to be achieved. A very high one
  • printable, low viscosity oxide media of the present invention which can be prepared by a sol-gel process.
  • these oxide media can be produced by suitable additives as printable doping media.
  • novel doping media can be synthesized on the basis of the sol-gel process and, if this is necessary, can be further formulated.
  • the synthesis of the doping ink can be achieved by adding
  • Condensation initiators e.g. be controlled by a carboxylic anhydride in the absence of water. In this way, the degree of crosslinking in the ink is above the stoichiometry of the addition,
  • the acid anhydride for example, the acid anhydride, controllable.
  • the resulting ink is low viscosity and low viscosity. As a result, it is perfectly processable with suitable printing methods.
  • Suitable printing methods can be the following: Spin or Dip Coating, Drop Casting, Curtain or Slot Dye Coating, Screen or Flexo Printing, Gravure or Ink Jet or Aerosol Jet Printing, Offset Printing, Microcontact Printing, Electrohydrodynamic Dispensing, Roller or Spray Coating, Ultrasonic Spray Coating, Pipe Jetting, Laser Transfer Printing, Päd Printing, Flatbed Screen Printing and Rotary Screen Printing. This list is not exhaustive, and other printing methods may be suitable.
  • the properties of the doping media according to the invention can be adjusted in a targeted manner, so that they are optimally suitable for special printing processes and for application to specific surfaces, with which they can interact intensively. In this way you can target properties, such as
  • particulate additives eg aluminum hydroxides and
  • particulate additives eg aluminum hydroxides and
  • each printing and coating method has its own requirements for the ink to be printed.
  • parameters to be set individually for the respective printing method are those such as the surface tension, the
  • Viscosity and the total vapor pressure of the ink Viscosity and the total vapor pressure of the ink.
  • the printable media in addition to their use as a doping source as scratch protection and corrosion protection layers, eg. Example, in the manufacture of components in the metal industry, preferably in the electronics industry, and in particular in the production of microelectronic, photovoltaic and microelectromechanical (MEMS) components, application.
  • photovoltaic components are in particular solar cells and modules.
  • applications in the electronics industry are characterized by the use of said inks and pastes in the following, by way of example, but not exhaustive fields: fabrication of thin film solar cells from thin film solar modules, organic solar cell manufacturing, printed circuit and organic electronics manufacturing, manufacturing from
  • Display elements based on the technologies of thin-film transistors (TFT), liquid crystals (LCD), organic light-emitting diodes (OLED) and touch-sensitive capacitive and resistive sensors.
  • TFT thin-film transistors
  • LCD liquid crystals
  • OLED organic light-emitting diodes
  • the dopants prepared according to this method are:
  • Fig. 1 shows a 31 P-NMR measurement of an ink resulting in Example 1.
  • the chemical shift of free phosphoric acid is 0 ppm and is not detectable in this example.
  • the phosphoric acid must therefore be firmly bound in the Si0 2 matrix.
  • FIG. 2 shows the doping profiles of the doping tests as repeatable
  • a polished p-type silicon wafer is after HF cleaning with a phosphorus doped Si0 2 matrix according to Example 1 means
  • a resulting ECV profile of the diffused emitter is additionally shown the behavior of the auto and / or proximity doping.
  • the proximity is according to an arrangement of silicon wafers
  • FIG. 3 shows the ECV profiles of the above-described doping experiments.
  • Example 4 shows the ECV profiles of the above-described doping experiments.
  • a textured p-type silicon wafer is after HF cleaning with a phosphorus doped Si0 2 matrix according to Example 1 with isopropanol or a comparable solvent, defined by vapor pressure and / or Hansen-solubility parameter, ethyl acetate or a comparable
  • Solvent defined by vapor pressure and / or Hansen solubility parameter
  • butanol or a comparable solvent defined by vapor pressure and / or Hansen solubility parameter as
  • Solvent (mass ratio 1: 1: 0.25) printed by spray coating. After subsequent baking for 2 minutes on a hotplate (100 ° C), diffusion at 900 ° C for 15 minutes leads to a
  • FIG. Figure 4 shows a scanning electron micrograph (50,000X magnification) of the deposited diffusion layer on a pyramid of an alkaline textured (100) wafer. It is easy to see the homogeneous coverage of the surface by the sprayed-on PSG layer. The measured layer thickness is 44 nm.
  • FIG. 5 shows the sheet resistance distribution (top right) on a full-area ink deposited with doping medium according to example 1.
  • the ECV profile (bottom left) gives a typical measurement point on the sample.
  • a textured p-type silicon wafer is after HF cleaning with a phosphorus doped SiO 2 matrix according to Example 1, with
  • Dipropylene glycol monomethyl ether as solvent, locally printed by inkjet. After subsequent baking for 2 minutes on a hotplate (100 ° C), diffusion at 900 ° C for 15 minutes leads to a
  • a resultant ECV profile of the diffused emitter and a measurement 1 mm apart from the printed location are shown in FIG.
  • the surface concentrations of the two areas differed by a factor> 00.
  • Fig. 6 shows the ECV profile of the diffused emitter and a reference measurement 1 mm next to the printed area.
  • a polished p-type silicon wafer is after HF cleaning with a phosphorus doped Si0 2 matrix according to Example 1 means
  • Sheet resistance of 50 ⁇ / sqr determined via QSSPC measurement (quasi-stationary photoconductivity measurement) and read out at one
  • Injection density of 1 * 10 15 minority charge carriers / cm 3 demonstrated.
  • the life span is 130 ps.
  • the lifetime of a comparable but untreated, ie undoped, reference wafer is 320 ps.
  • the wafers are wet-chemically passivated by methanol-quinhydrone process.
  • FIG. 7 shows a comparative lifetime measurement of a p-type wafer doped with a commercially available doping ink against one
  • FIG. 8 compares the service life of a p-type wafer according to the procedure outlined above using a doping ink according to Example 1 of the lifetime of a commercially available doping ink.
  • the lifetime of the wafer coated with an ink of the invention is 520 ps, which is four times larger than that of the competitive approach.
  • the increase in lifetime is due to the optimized synthesis method using very pure chemicals and the adequate pre-purification of the solvents used.
  • Fig. 8 shows the comparative lifetime measurement of one using one prepared according to the optimized synthesis method and using adequately pretreated solvent treated wafers compared to a wafer after its doping with a commercially available doping ink.
  • a doping ink is prepared according to the following conditions: in a 250 ml flask, weigh 67.3 g of ethanol, 54.2 ethyl acetate, 13.3 g of acetic acid, 32.5 g of tetraethylorthosilicate, mix thoroughly and add 6.7 g of water. In this mixture, 1, 7 g of phosphorus pentoxide (P4O10) are dissolved and the mixture is heated to reflux for 24 h. After the synthesis of the doping ink is stored in a refrigerator at +8 ° C and used at certain time intervals for doping of silicon wafers. For this purpose, the ink is in each case by means of the spin coating process on a one-side polished, p-type wafer with a conductivity of 1-10 Q * cm
  • the wafer is dried at 00 ° C on a hot plate for 2 minutes and then fed to the doping in a conventional muffle furnace at 900 ° C for 20 minutes. After diffusion, the resulting PSG glass is removed from the wafer surface by dilute hydrofluoric acid ( ⁇ 2%) and the sheet resistance is determined by four-peak measurement.
  • the doping effect of the doping ink prepared according to this method demonstrates a pronounced time dependence of the doping effect to be observed. There is a proportional relationship: as the storage time of the doping medium increases, its doping capacity decreases. The doping medium shows no long-term storage stability.
  • Doping medium applied as a function of the storage time too Achieving layer resistance as a function of storage time of the doping medium during cooling.
  • the observation is furthermore independent of which type of phosphorus compound and in which order it is added: aqueous or crystalline phosphoric acid, polyphosphoric acid,
  • Phosphoric acid esters such as mono-, di- and tributyl phosphate or phosphorus pentoxide itself.
  • Mass fractions of the phosphor contained in the precursor substances still have a low doping effect as such, which are prepared with pentavalent phosphorus sources.
  • phosphonic acids may be, for example, phosphonic acid, dibutylphosphonate,
  • Solvents are given in the description). Alternatively, a solvent mixture according to Example 4 can be added in an appropriate amount. The resulting mixture is kept under
  • the doping ink may be synthesized using a mixture of tetraethyl orthosilicate and aluminum isobutylate.
  • the partial substitution of tetraethyl orthosilicate by aluminum isobutylate may require the substoichiometric addition of complexing ligands, such as those of acetylacetone, salicylic acid, 2,3-dihydroxy- and 3,4-dihydroxybenzoic acid, or mixtures thereof.
  • the doping was carried out at 950 ° C in a tube furnace for 30 minutes in a nitrogen atmosphere.
  • Tetrahydrofuran added.
  • the resulting mixture is brought to reflux using an oil bath (80 ° C).
  • 100 g of acetic anhydride are rapidly added dropwise from an attached dropping funnel.
  • 190 g is added to this mixture from another dropping funnel.
  • Tetraethylorthosilicate slowly added dropwise to the mixture introduced in the apparatus with vigorous stirring. After the addition of the tetraethyl orthosilicate, the temperature of the oil bath is raised to 20 ° C and the mixture is left under vigorous stirring for one hour at this temperature. The reaction is then followed by a
  • Solvent mixture consisting of 150 g of ethyl acetate, 600 g of isopropanol and 150 g of ethoxypropanol, quenched and refluxed for a further 60 minutes.
  • the doping ink enables a homogeneous spray coating of
  • the content of acetic anhydride in the reaction mixture according to this Example 10 can be varied. It has proven to be advantageous to use masses between 90 g and 380 g of the reactant.
  • the crosslinking of the oxide network can be determined by the amount of added acetic anhydride, the amount of tetrahydrofuran contained in the reaction mixture, the duration of the heating of the
  • Reaction mixture at 120 ° C, as well as the temperature of the heating are controlled.
  • the duration of heating can after complete Add all reactants between 30 minutes and 240 minutes.
  • inert solvents other tetra hydrofu ran other sufficiently polar and non-protic solubilizers, such as
  • a suitable capping agent such as preferably provided ethoxytrimethylsilane. It has proved to be advantageous, 10 ml to 50 ml of the capping material, in this case
  • Fig. 1 P-NMR profile of an ink according to Example 1.
  • the chemical shift of free phosphoric acid is 0 ppm and is not detectable in this example.
  • FIG. 2 Doping profiles of doping tests according to Example 2 with
  • Fig. 4 Scanning electron micrograph (50,000 times
  • the measured layer thickness is 44 nm.
  • FIG. 5 Sheet resistance distribution (top right) on a whole-area wafer treated with doping medium according to Example 1.
  • the ECV profile (bottom left) corresponds to a typical measurement point on the sample
  • Fig. 6 ECV profile of a diffused emitter and a
  • FIG. 7 Comparative lifetime measurement of a p-type wafer doped with a commercially available doping ink versus a comparable one.
  • FIG. 8 Comparative lifetime measurement of a wafer treated with a solvent produced according to the optimized synthesis method and using adequately pretreated solvent in comparison to a wafer after its doping with a commercially available doping ink
  • FIG. 9 Doping potential of a doping medium prepared according to Example 6; FIG. Layer resistance as a function of under cooling

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Electromagnetism (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Sustainable Development (AREA)
  • Inorganic Chemistry (AREA)
  • Wood Science & Technology (AREA)
  • Ceramic Engineering (AREA)
  • Photovoltaic Devices (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • Sustainable Energy (AREA)
  • Dispersion Chemistry (AREA)

Abstract

La présente invention concerne un nouveau procédé de production de substances d'oxydes à faible viscosité, imprimables, et leur utilisation dans la production de cellules solaires.
EP13817655.7A 2012-12-28 2013-12-18 Substances de dopage liquides destinées au dopage local de tranches de silicium Withdrawn EP2938760A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP13817655.7A EP2938760A1 (fr) 2012-12-28 2013-12-18 Substances de dopage liquides destinées au dopage local de tranches de silicium

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP12008660 2012-12-28
EP13005734 2013-12-10
EP13817655.7A EP2938760A1 (fr) 2012-12-28 2013-12-18 Substances de dopage liquides destinées au dopage local de tranches de silicium
PCT/EP2013/003839 WO2014101990A1 (fr) 2012-12-28 2013-12-18 Substances de dopage liquides destinées au dopage local de tranches de silicium

Publications (1)

Publication Number Publication Date
EP2938760A1 true EP2938760A1 (fr) 2015-11-04

Family

ID=49917636

Family Applications (1)

Application Number Title Priority Date Filing Date
EP13817655.7A Withdrawn EP2938760A1 (fr) 2012-12-28 2013-12-18 Substances de dopage liquides destinées au dopage local de tranches de silicium

Country Status (8)

Country Link
US (1) US20160218185A1 (fr)
EP (1) EP2938760A1 (fr)
JP (1) JP2016506631A (fr)
KR (1) KR20150103162A (fr)
CN (1) CN104870699A (fr)
SG (2) SG11201504934UA (fr)
TW (1) TW201439372A (fr)
WO (1) WO2014101990A1 (fr)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20170100628A (ko) * 2014-12-30 2017-09-04 메르크 파텐트 게엠베하 반도체를 도핑하기 위한 방법
US20170365734A1 (en) 2014-12-30 2017-12-21 Merck Patent Gmbh Laser doping of semiconductors
WO2016150549A2 (fr) * 2015-03-23 2016-09-29 Merck Patent Gmbh Encre imprimable destinée à être utilisée comme barrière antidiffusion et antialliage pour la fabrication de cellules solaires cristallines au silicium à haut rendement
WO2016150548A2 (fr) * 2015-03-23 2016-09-29 Merck Patent Gmbh Barrière antidiffusion et antialliage pâteuse imprimable pour la fabrication de cellules solaires cristallines au silicium à haut rendement
EP3284110A1 (fr) * 2015-04-15 2018-02-21 Merck Patent GmbH Milieux dopants, formant barrière à une diffusion parasitaire et imprimables, à base de sol-gel et destinés au dopage local de tranches de silicium
KR20170137878A (ko) * 2015-04-15 2017-12-13 메르크 파텐트 게엠베하 인 확산을 억제하는 인쇄가능한 도핑 매질을 이용하는 태양 전지의 제조 방법
CN108352413B (zh) 2015-10-25 2021-11-02 索拉昂德有限公司 双面电池制造方法
DE102018109571B4 (de) 2018-04-20 2021-09-02 Karlsruher Institut für Technologie Verfahren zum Dotieren von Halbleitern
CN109325294B (zh) * 2018-09-25 2023-08-11 云南电网有限责任公司电力科学研究院 一种火电机组空气预热器性能状态的证据表征构建方法
CN110518084B (zh) * 2019-08-06 2021-03-05 苏州腾晖光伏技术有限公司 一种镓局域掺杂的perc电池及其制备方法

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2245407B3 (fr) * 1973-09-19 1977-04-08 Texas Instruments Inc
JPS5534258A (en) * 1978-09-01 1980-03-10 Tokyo Denshi Kagaku Kabushiki Coating solution for forming silica film
JPH06181201A (ja) * 1992-12-11 1994-06-28 Kawasaki Steel Corp 半導体装置の絶縁膜およびその絶縁膜形成用塗布液
DE19910816A1 (de) * 1999-03-11 2000-10-05 Merck Patent Gmbh Dotierpasten zur Erzeugung von p,p+ und n,n+ Bereichen in Halbleitern
US7159421B2 (en) * 2002-07-16 2007-01-09 Agere Systems Inc. Manufacture of planar waveguides using sol-gel techniques
US7393469B2 (en) * 2003-07-31 2008-07-01 Ramazan Benrashid High performance sol-gel spin-on glass materials
US7297414B2 (en) * 2003-09-30 2007-11-20 Fujifilm Corporation Gas barrier film and method for producing the same
DE602005010747D1 (de) * 2005-01-13 2008-12-11 Cinv Ag Kohlenstoffnanopartikel enthaltende verbundwerkstoffe
WO2008122596A2 (fr) * 2007-04-05 2008-10-16 Cinvention Ag Composition d'implant thérapeutique durcissable
US20100035422A1 (en) * 2008-08-06 2010-02-11 Honeywell International, Inc. Methods for forming doped regions in a semiconductor material
US7951696B2 (en) * 2008-09-30 2011-05-31 Honeywell International Inc. Methods for simultaneously forming N-type and P-type doped regions using non-contact printing processes
JP2010267787A (ja) * 2009-05-14 2010-11-25 Sharp Corp 半導体装置の製造方法
WO2011074467A1 (fr) * 2009-12-18 2011-06-23 東レ株式会社 Procédé de fabrication de dispositif semi-conducteur et cellule solaire à jonction arrière

Also Published As

Publication number Publication date
WO2014101990A1 (fr) 2014-07-03
CN104870699A (zh) 2015-08-26
JP2016506631A (ja) 2016-03-03
TW201439372A (zh) 2014-10-16
US20160218185A1 (en) 2016-07-28
SG10201705326XA (en) 2017-07-28
SG11201504934UA (en) 2015-07-30
KR20150103162A (ko) 2015-09-09

Similar Documents

Publication Publication Date Title
EP2938760A1 (fr) Substances de dopage liquides destinées au dopage local de tranches de silicium
EP2938761A1 (fr) Substances de dopage destinées au dopage local de tranches de silicium
WO2014101987A1 (fr) Barrières de diffusion imprimables pour tranche de silicium
EP3241242A1 (fr) Dopage laser de semi-conducteurs
EP2683777A2 (fr) Barrière de métallisation à base d'oxyde d'aluminium
WO2016107662A1 (fr) Procédé pour doper des semiconducteurs
US20180122640A1 (en) Screen-printable boron doping paste with simultaneous inhibition of phosphorus diffusion in co-diffusion processes
EP3284109B1 (fr) Procédé de fabrication de cellules photovoltaïques à l'aide de milieux dopant inhibant la diffusion du phosphore et imprimables
WO2016150548A2 (fr) Barrière antidiffusion et antialliage pâteuse imprimable pour la fabrication de cellules solaires cristallines au silicium à haut rendement
EP2938762A1 (fr) Substances d'oxydes destinées à extraire par effet getter des impuretés de tranches de silicium
JP6295953B2 (ja) 太陽電池素子及びその製造方法、並びに太陽電池モジュール
KR20150036260A (ko) 패시베이션층 형성용 조성물, 패시베이션층이 형성된 반도체 기판, 패시베이션층이 형성된 반도체 기판의 제조 방법, 태양 전지 소자, 태양 전지 소자의 제조 방법 및 태양 전지
JP2014072437A (ja) 半導体基板パッシベーション膜形成用組成物、パッシベーション膜付半導体基板及びその製造方法、並びに太陽電池素子及びその製造方法
WO2016165810A1 (fr) Milieux dopants, formant barrière à une diffusion parasitaire et imprimables, à base de sol-gel et destinés au dopage local de tranches de silicium
WO2016150549A2 (fr) Encre imprimable destinée à être utilisée comme barrière antidiffusion et antialliage pour la fabrication de cellules solaires cristallines au silicium à haut rendement

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20150519

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

RIN1 Information on inventor provided before grant (corrected)

Inventor name: KOEHLER, INGO

Inventor name: DOLL, OLIVER

Inventor name: BARTH, SEBASTIAN

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20171206