WO2006077298A1 - Support for manufacturing a strip based on polycrystalline silicon - Google Patents

Support for manufacturing a strip based on polycrystalline silicon Download PDF

Info

Publication number
WO2006077298A1
WO2006077298A1 PCT/FR2005/051142 FR2005051142W WO2006077298A1 WO 2006077298 A1 WO2006077298 A1 WO 2006077298A1 FR 2005051142 W FR2005051142 W FR 2005051142W WO 2006077298 A1 WO2006077298 A1 WO 2006077298A1
Authority
WO
WIPO (PCT)
Prior art keywords
support
silicon
ribbons
manufacturing
polycrystalline silicon
Prior art date
Application number
PCT/FR2005/051142
Other languages
French (fr)
Inventor
Christian Belouet
Original Assignee
Solarforce
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 Solarforce filed Critical Solarforce
Priority to EP05825984A priority Critical patent/EP1874983A1/en
Publication of WO2006077298A1 publication Critical patent/WO2006077298A1/en

Links

Classifications

    • 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 System
    • H01L31/182—Special manufacturing methods for polycrystalline Si, e.g. Si ribbon, poly Si ingots, thin films of polycrystalline Si
    • 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
    • C30B28/00—Production of homogeneous polycrystalline material with defined structure
    • C30B28/04—Production of homogeneous polycrystalline material with defined structure from liquids
    • C30B28/10—Production of homogeneous polycrystalline material with defined structure from liquids by pulling from a melt
    • 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
    • C30B35/00—Apparatus not otherwise provided for, specially adapted for the growth, production or after-treatment of single crystals or of a homogeneous polycrystalline material with defined structure
    • 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 invention relates to a substantially planar elongated support for manufacturing a polycrystalline silicon-based strip.
  • the object of the invention is to produce silicon strips for the manufacture of silicon photovoltaic cells.
  • a first method of manufacturing a polycrystalline silicon strip by deposition on such a support is carried out by means of a crucible containing a molten silicon bath, said support being intended to be at least partially immersed in the bath and traversing substantially vertically in the direction of the length the equilibrium surface of the bath.
  • RST Silicon Tape on Temporary Carbon Substrate
  • the support consists of an expanded and laminated natural graphite primer coated entirely with a protective film of pyrolytic graphite lamellar texture of a few micrometers thick. This coating is conventionally made at a high temperature of between 1900 and 2200 ° C., in an isothermal oven, by pyrolysis under reduced pressure of carbon compounds.
  • a second method of manufacturing a polycrystalline silicon strip by deposition on a support is carried out by means of a supply of molten silicon, said support being intended to be displaced substantially horizontally in the direction of the length and to receive the silicon on one of its longitudinal faces. This method is for example described in the patent document FR 2
  • the support can be of the same type as before and is drawn horizontally and asymmetrically covered. The silicon is finally deposited on one side of the support.
  • the lamellar texture pyrolytic graphite coating is highly resistant to molten silicon during the deposition process over periods of at least 20 seconds.
  • This excellent resistance which minimizes the formation of silicon carbide at nanometric thicknesses, subsequently makes it possible to completely burn the substrate at high temperature at 800 or 1200 ° C. and to prepare self-supported silicon layers.
  • This type of substrate allows symmetrical vertical pulling, according to the "RST” method, to obtain on either side of the support silicon films whose thickness can be adjusted between 50 and 300 microns or less.
  • the primary carbon ribbon is today the cheapest substrate available on the market.
  • the subsequent operation of burning the support is long and in practice limits the width of the strips to about ten centimeters.
  • An alternative would be to separate the two layers of silicon, for example by mechanical means, to greatly accelerate the burning operation. Such separation routes which involve the implementation of delicate manipulations, are very difficult to achieve, given the fragility of the silicon layers.
  • the second horizontal pulling method consists of depositing a silicon film from a bath located above the carbon support.
  • the rear face of the support is not exposed to silicon and therefore does not necessarily have to be coated with a protective film.
  • the use of a support coated on its two longitudinal sides of pyrolytic graphite results in a significant additional cost of the support.
  • the object of the invention is to provide a substantially planar elongated element intended in particular for the manufacture of a polycrystalline silicon-based strip that can be used for the implementation of these two processes, with a substantially vertical draw or draw substantially horizontal, while solving the technical problems mentioned above.
  • the invention proposes a substantially planar elongated element intended in particular for manufacturing a polycrystalline silicon-based strip and comprising a primary strip based on expanded and laminated natural graphite, characterized in that said primary ribbon is consisting of at least two secondary tapes superimposed and weakly adherent, said primary tape being coated on its two longitudinal sides with a second protective material.
  • Such an element can serve as a support for the manufacture of a polycrystalline silicon strip, whatever the trimming process, without loss of material and therefore without additional cost.
  • said secondary ribbons are co-laminated.
  • the first material is based on expanded natural graphite and laminated.
  • the second material is pyrolytic graphite of lamellar texture.
  • the invention also relates to a method for manufacturing a polycrystalline silicon-based strip by depositing on a support element as specified above, by means of a crucible containing a molten silicon bath, said support being intended to be immersed. at least partially in the bath and to pass substantially substantially vertically in the direction of the length of the equilibrium surface of the bath, characterized in that it also comprises a subsequent step of separating said secondary ribbons coated with silicon.
  • said separation step is followed by a step of burning the secondary ribbons.
  • said separation step is preceded by a step of cutting the edges of said secondary ribbons coated with silicon.
  • the duration of the burning operation is reduced by an order of magnitude, of the order of one hour to a few minutes. Ribbons of greater width can be used, allowing the realization of silicon wafers of greater width.
  • a machine for the continuous implementation of this method comprises in this order said crucible, a device for drawing said support covered with polycrystalline silicon layers, a device for separating the secondary ribbons and a burning device. of these secondary ribbons.
  • the invention finally relates to a method for manufacturing a polycrystalline silicon-based strip by depositing on a part of a support as specified above, by means of a supply of molten silicon, said support portion being intended for being moved substantially horizontally in the longitudinal direction and receiving the silicon on one of its longitudinal faces, characterized in that it comprises a preliminary step of separating said secondary ribbons from said support.
  • the support according to the invention it is thus possible to produce particularly thin silicon films, the thickness of which can be adjusted between 200 and 250 ⁇ m, or even less. According to the prior art, these films are of a thickness of the order of 350 to 450 microns or more.
  • the method also comprises a step of burning the secondary ribbon.
  • the cost of the carbon ribbon is reduced by a factor close to two.
  • the invention makes it possible, thanks to rapid burning at high temperature, to minimize the thickness of the silicon layer at values much lower than those currently obtained by current methods.
  • the invention is particularly suitable for continuous printing.
  • Figure 1 is a sectional view in perspective illustrating the first manufacturing method according to the invention and in detail an element according to the invention in longitudinal section.
  • Figure 2 is a schematic view of a manufacturing machine according to the invention.
  • Figure 3 is a longitudinal sectional view illustrating the second manufacturing method according to the invention.
  • a first method of manufacturing a polycrystalline silicon-based strip by deposition on a support 1 is carried out by means of a crucible 2 containing a bath of molten silicon 3, the support being intended to be at least partially immersed in the bath and to cross in the direction represented by the arrow 5 substantially vertical, in the direction of the length, the equilibrium surface of the bath 4.
  • support 1 crosses a slot 6 arranged in the bottom of the crucible 2 and overlaps the equilibrium surface 4 of a silicon layer 7A, 7B on each of its longitudinal faces.
  • this low adhesion is achieved by co-rolling of the two secondary ribbons, the conditions of which are chosen to ensure the desired degree of adhesion.
  • Element 1 is a symmetrical structure with a complete coating, on both longitudinal faces 1B, 1B 'and on the edges, by the second protective material.
  • the secondary strips 1A, 1A ' are made of a natural expanded and laminated graphite material and the protective material is pyrolytic graphite of lamellar texture.
  • the two secondary strips 1A, 1A 'fulfill special conditions, which do not contravene the advantages of the known solution: low cost of the primary ribbon and minimal thermoelastic stresses induced in the silicon layers 7A, 7B. These conditions translate by a surface density and a minimum total thickness.
  • a known primary tape has a basis weight of the order of 160 g / cm 2 for a thickness of the order of 250 microns.
  • the primary ribbon will be obtained by co-laminating two secondary ribbons " IA, 1 A" in order to best approximate these characteristics for vertical draft, although less severe constraints on the density of the surface are feasible and still advantageous for the case of thick silicon layers.
  • This separation can be done by simple takeoff, after removal of silicon on the edges of the ribbons.
  • the opening of the ribbon field for example by laser cutting, allows to separate in half the support 1 covered with silicon. This separation is assisted by internal forces: under the effect of the stresses induced in the carbon by the contraction of the silicon layers, the composite tape splits in two according to the joining plane of the secondary ribbons 1A, 1A '.
  • the separation is done in a continuous process, in line with the draw. It is performed on the ribbon extracted from the draft frame before the thermoelastic stresses induced in the silicon layers 7A, 7B become too high, ie at high temperature, for example around 800 ° C. The two faces of carbon being then released, the operation of burning secondary ribbons and their protective material can be conducted immediately and easily. The two silicon strips 7A, 7B separated from the secondary ribbons are thus extracted continuously.
  • FIG. 2 a machine for the continuous implementation of this process is shown diagrammatically in FIG. 2 and comprises, in this order, the crucible 2, a drawing device 10 of the support covered with layers based on polycrystalline silicon, a device for separating 1 1 secondary ribbons each covered with a polycrystalline silicon layer and a burning device 12 of these secondary ribbons and their protective material.
  • the separation is performed before the burning operation on long composite strips, which have previously undergone cooling to a temperature which can reach room temperature and possibly various treatments.
  • a method of manufacturing a polycrystalline silicon-based strip by deposition on a support 1 ' is carried out, by means of a supply of molten silicon 3, the support being intended to be displaced in the direction of the arrow 5 'substantially horizontal, in the direction of the length and to receive the silicon on one of its longitudinal faces.
  • a support 1 as shown in FIG. 1 is initially used.
  • This support 1 which is shown in detail in FIG. 1, comprises a primary tape of a first material consisting of at least two secondary tapes 1A, 1A 'which are weakly adherent and coated with a second protective material 1B, 1B'.
  • this low adhesion is achieved by co-rolling of the two secondary ribbons, the conditions of which are chosen to ensure the desired degree of adhesion.
  • the support 1 is a symmetrical structure with a complete coating, on both longitudinal faces 1B, 1B 'and on the edges, with pyrolytic graphite lamellar texture.
  • the secondary strips 1A, 1A ' are made of a natural expanded and laminated graphite material and the protective material is pyrolytic graphite of lamellar texture.
  • the secondary ribbons 1A, 1A ' Prior to the deposition phase illustrated in FIG. 3, the secondary ribbons 1A, 1A 'are separated and each half 1' of this initial support 1 is used separately and covered on its upper face coated with silicon 1B protective material. 3 This separation is performed by simply opening the edge of the support 1. This can be achieved mechanically at high speed on industrial cutting machines or more slowly by laser cutting.
  • the secondary tape 1 A (or " I A") with its protective material 1 B (or 1 B ') is then burned to obtain a silicon film.

Abstract

The invention relates to an elongated, essentially flat element (1) provided, in particular, for manufacturing a strip based on polycrystalline silicon and comprising a primary ribbon based on expanded and laminated natural graphite. According to the invention, this primary ribbon is constituted of at least two ribbons (1A, 1A') called secondary ribbons that are superimposed and have a weak adherence, said primary ribbon being coated on its two longitudinal sides with a second protective material (1B, 1B').

Description

SUPPORT POUR LA FABRICATION DE BANDE A BASE DE SILICIUM POLYCRISTALLINSUPPORT FOR THE MANUFACTURE OF POLYCRYSTALLINE SILICON STRIP
L'invention concerne un support allongé sensiblement plan destiné à la fabrication d'une bande à base de silicium polycristallin.The invention relates to a substantially planar elongated support for manufacturing a polycrystalline silicon-based strip.
L'objet de l'invention est de réaliser des bandes de silicium pour la fabrication de cellules photovoltaïques en silicium.The object of the invention is to produce silicon strips for the manufacture of silicon photovoltaic cells.
Un premier procédé de fabrication d'une bande à base de silicium polycristallin par dépôt sur un tel support, est réalisé au moyen d'un creuset contenant un bain de silicium fondu, ledit support étant destiné à être plongé au moins partiellement dans le bain et à traverser sensiblement verticalement dans le sens de la longueur la surface d'équilibre du bain.A first method of manufacturing a polycrystalline silicon strip by deposition on such a support is carried out by means of a crucible containing a molten silicon bath, said support being intended to be at least partially immersed in the bath and traversing substantially vertically in the direction of the length the equilibrium surface of the bath.
Ce procédé, appelé procédé « RST » (pour Ruban de silicium sur Substrat de carbone Temporaire), est décrit dans plusieurs documents de brevets, par exemple FR 2 386 359, FR 2 550 965 ou FR 2 568 490.This process, called the "RST" method (for Silicon Tape on Temporary Carbon Substrate), is described in several patent documents, for example FR 2,386,359, FR 2,550,965 or FR 2,568,490.
Le support est constitué d'un ruban primaire en graphite naturel expansé et laminé, revêtu entièrement d'un film protecteur de graphite pyrolytique de texture lamellaire de quelques micromètres d'épaisseur. Ce revêtement est classiquement réalisé à haute température comprise entre 1900 et 2200°C, dans un four isotherme, par pyrolyse sous pression réduite de composés carbonés.The support consists of an expanded and laminated natural graphite primer coated entirely with a protective film of pyrolytic graphite lamellar texture of a few micrometers thick. This coating is conventionally made at a high temperature of between 1900 and 2200 ° C., in an isothermal oven, by pyrolysis under reduced pressure of carbon compounds.
L'élimination ultérieure du support de carbone ainsi inséré entre deux couches de silicium se fait typiquement par brûlage à haute température à partir des chants du ruban obtenu, par exemple ouverts par découpe laser. Un second procédé de fabrication d'une bande à base de silicium polycristallin par dépôt sur un support est réalisé au moyen d'un apport de silicium fondu, ledit support étant destiné à être déplacé sensiblement horizontalement dans le sens de la longueur et à recevoir le silicium sur une de ses faces longitudinales. Ce procédé est par exemple décrit dans le document de brevet FR 2The subsequent removal of the carbon support thus inserted between two silicon layers is typically by burning at high temperature from the edges of the ribbon obtained, for example opened by laser cutting. A second method of manufacturing a polycrystalline silicon strip by deposition on a support is carried out by means of a supply of molten silicon, said support being intended to be displaced substantially horizontally in the direction of the length and to receive the silicon on one of its longitudinal faces. This method is for example described in the patent document FR 2
529 189. Le support peut être du même type que précédemment et est tiré horizontalement et recouvert de façon asymétrique. Le silicium est finalement déposé sur une seule face du support.529 189. The support can be of the same type as before and is drawn horizontally and asymmetrically covered. The silicon is finally deposited on one side of the support.
Un tel support connu présente des avantages. Le revêtement de graphite pyrolytique de texture lamellaire résiste parfaitement au silicium fondu pendant l'opération de dépôt, sur des périodes d'au moins 20 secondes.Such a known support has advantages. The lamellar texture pyrolytic graphite coating is highly resistant to molten silicon during the deposition process over periods of at least 20 seconds.
Cette excellente résistance, qui minimise la formation de carbure de silicium à des épaisseurs nanométriques, permet ultérieurement de brûler complètement le substrat à haute température vers 800 ou 1200°C et de préparer des couches de silicium auto supportées.This excellent resistance, which minimizes the formation of silicon carbide at nanometric thicknesses, subsequently makes it possible to completely burn the substrate at high temperature at 800 or 1200 ° C. and to prepare self-supported silicon layers.
Ce type de substrat permet en tirage vertical symétrique, selon le procédé « RST », d'obtenir de part et d'autre du support des films de silicium dont l'épaisseur peut être ajustée entre 50 et 300 μm, voire moins. Le ruban de carbone primaire est aujourd'hui le substrat le moins cher disponible sur le marché.This type of substrate allows symmetrical vertical pulling, according to the "RST" method, to obtain on either side of the support silicon films whose thickness can be adjusted between 50 and 300 microns or less. The primary carbon ribbon is today the cheapest substrate available on the market.
Cependant, un tel support connu présente les problèmes techniques suivants.However, such known support has the following technical problems.
Selon le premier procédé, l'opération ultérieure de brûlage du support est longue et limite en pratique la largeur des bandes à une dizaine de centimètres. Une alternative consisterait à séparer les deux couches de silicium, par des voies mécaniques par exemple, afin d'accélérer considérablement l'opération de brûlage. De telles voies de séparation qui impliquent la mise en œuvre de manipulations délicates, sont très difficilement réalisables, compte tenu de la fragilité des couches de silicium.According to the first method, the subsequent operation of burning the support is long and in practice limits the width of the strips to about ten centimeters. An alternative would be to separate the two layers of silicon, for example by mechanical means, to greatly accelerate the burning operation. Such separation routes which involve the implementation of delicate manipulations, are very difficult to achieve, given the fragility of the silicon layers.
Le second procédé par tirage horizontal consiste à déposer un film de silicium à partir d'un bain situé au-dessus du support de carbone. Dans cette configuration, la face arrière du support n'est pas exposée au silicium et ne doit donc pas nécessairement être revêtue d'un film protecteur. L'utilisation d'un support revêtu sur ses deux faces longitudinales de graphite pyrolytique entraîne un surcoût significatif inutile du support. Le but de l'invention est de proposer un élément allongé sensiblement plan destiné en particulier à la fabrication d'une bande à base de silicium polycristallin qui puisse être utilisé pour la mise en œuvre de ces deux procédés, à tirage sensiblement vertical ou à tirage sensiblement horizontal, tout en résolvant les problèmes techniques évoqués ci-dessus.The second horizontal pulling method consists of depositing a silicon film from a bath located above the carbon support. In this configuration, the rear face of the support is not exposed to silicon and therefore does not necessarily have to be coated with a protective film. The use of a support coated on its two longitudinal sides of pyrolytic graphite results in a significant additional cost of the support. The object of the invention is to provide a substantially planar elongated element intended in particular for the manufacture of a polycrystalline silicon-based strip that can be used for the implementation of these two processes, with a substantially vertical draw or draw substantially horizontal, while solving the technical problems mentioned above.
Pour ce faire l'invention propose un élément allongé sensiblement plan destiné en particulier à la fabrication d'une bande à base de silicium polycristallin et comprenant un ruban primaire à base de graphite naturel expansé et laminé,, caractérisé en ce que ledit ruban primaire est constitué d'au moins deux rubans dits secondaires superposés et faiblement adhérents, ledit ruban primaire étant revêtu sur ses deux faces longitudinales d'un second matériau protecteur.To this end, the invention proposes a substantially planar elongated element intended in particular for manufacturing a polycrystalline silicon-based strip and comprising a primary strip based on expanded and laminated natural graphite, characterized in that said primary ribbon is consisting of at least two secondary tapes superimposed and weakly adherent, said primary tape being coated on its two longitudinal sides with a second protective material.
Un tel élément peut servir de support destiné à la fabrication d'une bande à base de silicium polycristallin, quel que soit le procédé de trage, sans perte de matière et donc sans surcoût.Such an element can serve as a support for the manufacture of a polycrystalline silicon strip, whatever the trimming process, without loss of material and therefore without additional cost.
Selon un mode de réalisation préféré de l'invention, lesdits rubans secondaires sont co-laminés.According to a preferred embodiment of the invention, said secondary ribbons are co-laminated.
Avantageusement, le premier matériau est à base de graphite naturel expansé et laminé. Avantageusement, le second matériau est du graphite pyrolytique de texture lamellaire.Advantageously, the first material is based on expanded natural graphite and laminated. Advantageously, the second material is pyrolytic graphite of lamellar texture.
L'invention concerne également un procédé de fabrication d'une bande à base de silicium polycristallin par dépôt sur un élément support tel que précisé plus haut, au moyen d'un creuset contenant un bain de silicium fondu, ledit support étant destiné à être plongé au moins partiellement dans le bain et à traverser sensiblement verticalement dans le sens de la longueur la surface d'équilibre du bain, caractérisé en ce qu'il comporte également une étape ultérieure de séparation desdits rubans secondaires recouverts de silicium. Selon un mode de réalisation préféré, ladite étape de séparation est suivie d'une étape de brûlage des rubans secondaires. Avantageusement, ladite étape de séparation est précédée d'une étape de découpe des bords desdits rubans secondaires recouverts de silicium.The invention also relates to a method for manufacturing a polycrystalline silicon-based strip by depositing on a support element as specified above, by means of a crucible containing a molten silicon bath, said support being intended to be immersed. at least partially in the bath and to pass substantially substantially vertically in the direction of the length of the equilibrium surface of the bath, characterized in that it also comprises a subsequent step of separating said secondary ribbons coated with silicon. According to a preferred embodiment, said separation step is followed by a step of burning the secondary ribbons. Advantageously, said separation step is preceded by a step of cutting the edges of said secondary ribbons coated with silicon.
Grâce à l'invention, la durée de l'opération de brûlage est réduite d'un ordre de grandeur, de l'ordre d'une heure à quelques minutes. Des rubans de largeur supérieure peuvent être utilisés, permettant la réalisation de plaques de silicium de plus grande largeur.Thanks to the invention, the duration of the burning operation is reduced by an order of magnitude, of the order of one hour to a few minutes. Ribbons of greater width can be used, allowing the realization of silicon wafers of greater width.
De préférence, une machine pour la mise en œuvre en continu de ce procédé, comprend dans cet ordre ledit creuset, un dispositif de tirage dudit support recouvert de couches à base de silicium polycristallin, un dispositif de séparation des rubans secondaires et un dispositif de brûlage de ces rubans secondaires.Preferably, a machine for the continuous implementation of this method comprises in this order said crucible, a device for drawing said support covered with polycrystalline silicon layers, a device for separating the secondary ribbons and a burning device. of these secondary ribbons.
L'invention concerne enfin un procédé de fabrication d'une bande à base de silicium polycristallin par dépôt sur une partie d'un support tel que précisé plus haut, au moyen d'un apport de silicium fondu, ladite partie de support étant destinée à être déplacée sensiblement horizontalement dans le sens de la longueur et à recevoir le silicium sur une de ses faces longitudinales, caractérisé en ce qu'il comporte une étape préliminaire de séparation desdits rubans secondaires dudit support. Grâce au support conforme à l'invention, il est possible de réaliser ainsi des films de silicium particulièrement minces, dont l'épaisseur peut être ajustée entre 200 et 250 μm, voire moins. Selon l'art antérieur, ces films sont d'une épaisseur de l'ordre de 350 à 450 μm, voire plus.The invention finally relates to a method for manufacturing a polycrystalline silicon-based strip by depositing on a part of a support as specified above, by means of a supply of molten silicon, said support portion being intended for being moved substantially horizontally in the longitudinal direction and receiving the silicon on one of its longitudinal faces, characterized in that it comprises a preliminary step of separating said secondary ribbons from said support. Thanks to the support according to the invention, it is thus possible to produce particularly thin silicon films, the thickness of which can be adjusted between 200 and 250 μm, or even less. According to the prior art, these films are of a thickness of the order of 350 to 450 microns or more.
Selon un mode de réalisation préféré, le procédé comporte également une étape de brûlage du ruban secondaire.According to a preferred embodiment, the method also comprises a step of burning the secondary ribbon.
Grâce à l'invention, le coût du ruban de carbone est réduit d'un facteur proche de deux. L'invention permet, grâce à un brûlage rapide à haute température de minimiser l'épaisseur de la couche de silicium à des valeurs très inférieures à celle couramment obtenues par les procédés actuels. L'invention est particulièrement adaptée à un tirage continu.Thanks to the invention, the cost of the carbon ribbon is reduced by a factor close to two. The invention makes it possible, thanks to rapid burning at high temperature, to minimize the thickness of the silicon layer at values much lower than those currently obtained by current methods. The invention is particularly suitable for continuous printing.
L'invention est décrite ci-après plus en détail à l'aide de figures ne représentant qu'un mode de réalisation préféré de l'invention. La figure 1 est une vue en coupe et en perspective illustrant le premier procédé de fabrication conforme à l'invention ainsi qu'en détail un élément conforme à l'invention en coupe longitudinale.The invention is described below in more detail with the aid of figures representing only a preferred embodiment of the invention. Figure 1 is a sectional view in perspective illustrating the first manufacturing method according to the invention and in detail an element according to the invention in longitudinal section.
La figure 2 est une vue schématique d'une machine de fabrication conforme à l'invention.Figure 2 is a schematic view of a manufacturing machine according to the invention.
La figure 3 est une vue en coupe longitudinale illustrant le second procédé de fabrication conforme à l'invention.Figure 3 is a longitudinal sectional view illustrating the second manufacturing method according to the invention.
Comme illustré sur la figure 1 , un premier procédé de fabrication d'une bande à base de silicium polycristallin par dépôt sur un support 1 est réalisé au moyen d'un creuset 2 contenant un bain de silicium fondu 3, le support étant destiné à être plongé au moins partiellement dans le bain et à traverser dans le sens représenté par la flèche 5 sensiblement verticale, dans le sens de la longueur, la surface d'équilibre du bain 4.As illustrated in FIG. 1, a first method of manufacturing a polycrystalline silicon-based strip by deposition on a support 1 is carried out by means of a crucible 2 containing a bath of molten silicon 3, the support being intended to be at least partially immersed in the bath and to cross in the direction represented by the arrow 5 substantially vertical, in the direction of the length, the equilibrium surface of the bath 4.
Pour ce faire, félément support 1 traverse une fente 6 agencée dans le fond du creuset 2 et se recouvre à la surface d'équilibre 4 d'une couche de silicium 7A, 7B sur chacune de ses faces longitudinales.For this purpose, support 1 crosses a slot 6 arranged in the bottom of the crucible 2 and overlaps the equilibrium surface 4 of a silicon layer 7A, 7B on each of its longitudinal faces.
Selon l'invention, l'élément 1 qui est représenté en détail sur la figure 1 comprend un ruban primaire en un premier matériau constitué d'au moins deux rubans secondaires 1A, 1 A' superposés et faiblement adhérents et revêtu d'un second matériau protecteur 1 B, 1 B'. Avantageusement, cette faible adhérence est réalisée par co-laminage des deux rubans secondaires, dont les conditions sont choisies pour assurer le degré d'adhérence voulu.According to the invention, the element 1 which is shown in detail in FIG. 1 comprises a primary ribbon of a first material consisting of at least two secondary strips 1A, 1A 'superimposed and weakly adherent and coated with a second material protector 1B, 1B '. Advantageously, this low adhesion is achieved by co-rolling of the two secondary ribbons, the conditions of which are chosen to ensure the desired degree of adhesion.
L'élément 1 est une structure symétrique avec un revêtement complet, sur les deux faces longitudinales 1 B, 1 B' et sur les bords, par le second matériau protecteur.Element 1 is a symmetrical structure with a complete coating, on both longitudinal faces 1B, 1B 'and on the edges, by the second protective material.
De préférence, les rubans secondaires 1 A, 1 A' sont constitués d'un matériau à base de graphite naturel expansé et laminé et le matériau protecteur est du graphite pyrolytique de texture lamellaire.Preferably, the secondary strips 1A, 1A 'are made of a natural expanded and laminated graphite material and the protective material is pyrolytic graphite of lamellar texture.
Les deux rubans secondaires 1A, 1 A' remplissent des conditions particulières, qui ne contreviennent pas aux avantages de la solution connue : faible coût du ruban primaire et contraintes thermo-élastiques minimales induites dans les couches de silicium 7A, 7B. Ces conditions se traduisent par une masse surfacique et une épaisseur totale minimale. Un ruban primaire connu a une masse surfacique de l'ordre de 160 g/cm2 pour une épaisseur de l'ordre de 250 μm. Le ruban primaire sera obtenu par co- laminage de deux rubans secondaires "I A, 1 A' de façon à approcher au mieux ces caractéristiques pour le tirage vertical. Des contraintes moins sévères sur la densité surfacique sont néanmoins réalisables et encore avantageuses pour le cas des couches de silicium épaisses.The two secondary strips 1A, 1A 'fulfill special conditions, which do not contravene the advantages of the known solution: low cost of the primary ribbon and minimal thermoelastic stresses induced in the silicon layers 7A, 7B. These conditions translate by a surface density and a minimum total thickness. A known primary tape has a basis weight of the order of 160 g / cm 2 for a thickness of the order of 250 microns. The primary ribbon will be obtained by co-laminating two secondary ribbons " IA, 1 A" in order to best approximate these characteristics for vertical draft, although less severe constraints on the density of the surface are feasible and still advantageous for the case of thick silicon layers.
En sortie de cette phase de dépôt, illustrée sur la figure 1 , est réalisée une étape ultérieure de séparation des rubans secondaires "I A, "I A' recouverts de silicium.The output of this deposition phase, illustrated in Figure 1, is carried out a subsequent step of separation of the secondary tape "IA" IA 'covered with silicon.
Cette séparation peut se faire par simple décollage, après élimination du silicium sur les bords des rubans. L'ouverture du champ du ruban par exemple par découpe laser, permet de séparer en deux le support 1 recouvert de silicium. Cette séparation est assistée par des forces internes : sous l'effet des contraintes induites dans le carbone par la contraction des couches de silicium, le ruban composite se sépare en deux suivant le plan d'accolage des rubans secondaires 1 A, 1 A'.This separation can be done by simple takeoff, after removal of silicon on the edges of the ribbons. The opening of the ribbon field for example by laser cutting, allows to separate in half the support 1 covered with silicon. This separation is assisted by internal forces: under the effect of the stresses induced in the carbon by the contraction of the silicon layers, the composite tape splits in two according to the joining plane of the secondary ribbons 1A, 1A '.
Dans une première variante, la séparation se fait suivant un procédé continu, en ligne avec le tirage. Elle est réalisée sur le ruban extrait du bâti de tirage avant que les contraintes thermo-élastiques induites dans les couches de silicium 7A, 7B ne deviennent trop importantes c'est-à-dire à température élevée, par exemple vers 800 °C. Les deux faces de carbone étant alors dégagées, l'opération de brûlage des rubans secondaires et de leur matériau protecteur peut être conduite aussitôt et facilement. Les deux bandes de silicium 7A, 7B séparées des rubans secondaires sont ainsi extraites en continu.In a first variant, the separation is done in a continuous process, in line with the draw. It is performed on the ribbon extracted from the draft frame before the thermoelastic stresses induced in the silicon layers 7A, 7B become too high, ie at high temperature, for example around 800 ° C. The two faces of carbon being then released, the operation of burning secondary ribbons and their protective material can be conducted immediately and easily. The two silicon strips 7A, 7B separated from the secondary ribbons are thus extracted continuously.
Dans ce cas, une machine pour la mise en œuvre en continu de ce procédé est schématisée sur la figure 2 et comprend dans cet ordre le creuset 2, un dispositif de tirage 10 du support recouvert de couches à base de silicium polycristallin, un dispositif de séparation 1 1 des rubans secondaires recouverts chacun d'une couche à base de silicium polycristallin et un dispositif de brûlage 12 de ces rubans secondaires et de leur matériau protecteur.In this case, a machine for the continuous implementation of this process is shown diagrammatically in FIG. 2 and comprises, in this order, the crucible 2, a drawing device 10 of the support covered with layers based on polycrystalline silicon, a device for separating 1 1 secondary ribbons each covered with a polycrystalline silicon layer and a burning device 12 of these secondary ribbons and their protective material.
Dans une seconde variante, adaptée à un procédé discontinu, la séparation est pratiquée avant l'opération de brûlage sur des bandes composite de grande longueur, qui ont préalablement subi le refroidissement à une température qui peut atteindre la température ambiante et éventuellement divers traitements.In a second variant, adapted to a batch process, the separation is performed before the burning operation on long composite strips, which have previously undergone cooling to a temperature which can reach room temperature and possibly various treatments.
Comme illustré sur la figure 3, un procédé de fabrication d'une bande à base de silicium polycristallin par dépôt sur un support 1 ' est réalisé, au moyen d'un apport de silicium fondu 3, le support étant destiné à être déplacé dans le sens de la flèche 5' sensiblement horizontale, dans le sens de la longueur et à recevoir le silicium sur une de ses faces longitudinales.As illustrated in FIG. 3, a method of manufacturing a polycrystalline silicon-based strip by deposition on a support 1 'is carried out, by means of a supply of molten silicon 3, the support being intended to be displaced in the direction of the arrow 5 'substantially horizontal, in the direction of the length and to receive the silicon on one of its longitudinal faces.
Selon ce procédé, un support 1 comme représenté sur la figure 1 est initialement utilisé. Ce support 1 qui est représenté en détail sur la figure 1 comprend un ruban primaire en un premier matériau constitué d'au moins deux rubans secondaires 1A, 1 A' faiblement adhérents et revêtu d'un second matériau protecteur 1 B, 1 B'. Avantageusement, cette faible adhérence est réalisée par co-laminage des deux rubans secondaires, dont les conditions sont choisies pour assurer le degré d'adhérence voulu.According to this method, a support 1 as shown in FIG. 1 is initially used. This support 1, which is shown in detail in FIG. 1, comprises a primary tape of a first material consisting of at least two secondary tapes 1A, 1A 'which are weakly adherent and coated with a second protective material 1B, 1B'. Advantageously, this low adhesion is achieved by co-rolling of the two secondary ribbons, the conditions of which are chosen to ensure the desired degree of adhesion.
Le support 1 est une structure symétrique avec un revêtement complet, sur les deux faces longitudinales 1 B, 1 B' et sur les bords, par du graphite pyrolytique de texture lamellaire.The support 1 is a symmetrical structure with a complete coating, on both longitudinal faces 1B, 1B 'and on the edges, with pyrolytic graphite lamellar texture.
De préférence, les rubans secondaires 1 A, 1 A' sont constitués d'un matériau à base de graphite naturel expansé et laminé et le matériau protecteur est du graphite pyrolytique de texture lamellaire.Preferably, the secondary strips 1A, 1A 'are made of a natural expanded and laminated graphite material and the protective material is pyrolytic graphite of lamellar texture.
Préalablement à la phase de dépôt illustrée sur la figure 3, les rubans secondaires 1 A, 1 A' sont séparés et chaque moitié 1 ' de ce support initial 1 est utilisée séparément et recouverte sur sa face supérieure revêtue de matériau protecteur 1 B de silicium 3 Cette séparation est effectuée par simple ouverture du chant du support 1. Ceci peut être réalisé par voie mécanique à grande vitesse sur des machines de découpe industrielles ou plus lentement par découpe laser. Le ruban secondaire 1 A (ou "I A') avec son matériau protecteur 1 B (ou 1 B') est ensuite brûlé pour obtenir un film de silicium. Prior to the deposition phase illustrated in FIG. 3, the secondary ribbons 1A, 1A 'are separated and each half 1' of this initial support 1 is used separately and covered on its upper face coated with silicon 1B protective material. 3 This separation is performed by simply opening the edge of the support 1. This can be achieved mechanically at high speed on industrial cutting machines or more slowly by laser cutting. The secondary tape 1 A (or " I A") with its protective material 1 B (or 1 B ') is then burned to obtain a silicon film.

Claims

REVENDICATIONS
1. Elément (1 ) allongé sensiblement plan destiné en particulier à la fabrication d'une bande à base de silicium polycristallin et comprenant un ruban primaire à base de graphite naturel expansé et laminé , caractérisé en ce que ledit ruban primaire est constitué d'au moins deux rubans ("IA, "IA') dits secondaires superposés et faiblement adhérents, ledit ruban primaire étant revêtu sur ses deux faces longitudinales d'un second matériau protecteur (1 B, 1 B'). 1. Elongated substantially flat element (1) intended in particular for the manufacture of a polycrystalline silicon-based strip and comprising a primary strip based on expanded and laminated natural graphite, characterized in that said primary strip consists of at least two ribbons ( " IA, " IA ') said superimposed secondary and weakly adherent, said primary ribbon being coated on its two longitudinal sides with a second protective material (1 B, 1 B').
2. Elément selon la revendication précédente, caractérisé en ce que lesdits rubans secondaires ("I A, "I A') sont co-laminés.2. Element according to the preceding claim, characterized in that said secondary ribbons ( " IA, " I A ') are co-laminated.
3. Elément selon Tune des revendications précédentes, caractérisé en ce que le second matériau est du graphite pyrolytique de texture lamellaire. 3. Element according to one of the preceding claims, characterized in that the second material is pyrolytic graphite lamellar texture.
4. Procédé de fabrication d'une bande à base de silicium polycristallin par dépôt sur un élément support (1 ) selon l'une des revendications précédentes, au moyen d'un creuset (2) contenant un bain de silicium fondu (3), ledit support étant destiné à être plongé au moins partiellement dans le bain et à traverser sensiblement verticalement dans le sens de la longueur la surface d'équilibre du bain (4), caractérisé en ce qu'il comporte également une étape ultérieure de séparation desdits rubans secondaires (1 A, 1 A') recouverts de silicium.4. Process for manufacturing a polycrystalline silicon-based strip by depositing on a support element (1) according to one of the preceding claims, by means of a crucible (2) containing a molten silicon bath (3), said support being intended to be at least partially immersed in the bath and to pass substantially substantially vertically in the direction of the length of the equilibrium surface of the bath (4), characterized in that it also comprises a subsequent step of separating said ribbons; secondary (1A, 1A ') coated with silicon.
5. Procédé de fabrication selon la revendication 4, caractérisé en ce que ladite étape de séparation est suivie d'une étape de brûlage des rubans secondaires (1 A, 1 A').5. Manufacturing process according to claim 4, characterized in that said separation step is followed by a step of burning the secondary ribbons (1A, 1A ').
6. Procédé de fabrication selon la revendication 4 ou 5, caractérisé en ce que ladite étape de séparation est précédée d'une étape de découpe des bords desdits rubans secondaires (1 A, 1 A') recouverts de silicium.6. The manufacturing method according to claim 4 or 5, characterized in that said separating step is preceded by a step of cutting the edges of said secondary ribbons (1A, 1A ') covered with silicon.
7. Machine pour la mise en œuvre en continu du procédé selon la revendication 4 à 6, caractérisée en ce qu'elle comprend dans cet ordre ledit creuset (2) , un dispositif de tirage (10) dudit support recouvert de couches à base de silicium polycristallin, un dispositif de séparation (1 1 ) des rubans secondaires (1 A, 1 A') et un dispositif de brûlage (12) de ces rubans secondaires.7. Machine for the continuous implementation of the process according to claim 4 to 6, characterized in that it comprises in this order said crucible (2), a drawing device (10) of said support covered with polycrystalline silicon layers, a separating device (1 1) of the secondary ribbons (1 A, 1 A ') and a burning device (12) of these secondary ribbons.
8. Procédé de fabrication d'une bande à base de silicium polycristallin par dépôt sur une partie d'un support (1 ) selon l'une des revendications 1 à8. A method of manufacturing a polycrystalline silicon-based strip by depositing on a part of a support (1) according to one of claims 1 to
3, au moyen d'un apport de silicium fondu (3) , ladite partie de support étant destinée à être déplacé sensiblement horizontalement dans le sens de la longueur et à recevoir le silicium sur une de ses faces longitudinales, caractérisé en ce qu'il comporte une étape préliminaire de séparation desdits rubans secondaires (1 A, 1 A') dudit support.3, by means of a supply of molten silicon (3), said support portion being intended to be displaced substantially horizontally in the direction of the length and to receive the silicon on one of its longitudinal faces, characterized in that comprises a preliminary step of separating said secondary ribbons (1 A, 1 A ') from said support.
9. Procédé de fabrication selon la revendication 8, caractérisé en ce qu'il comporte également une étape de brûlage du ruban secondaire (1 A ou 1 A'). 9. The manufacturing method according to claim 8, characterized in that it also comprises a step of burning the secondary tape (1 A or 1 A ').
PCT/FR2005/051142 2005-01-19 2005-12-22 Support for manufacturing a strip based on polycrystalline silicon WO2006077298A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP05825984A EP1874983A1 (en) 2005-01-19 2005-12-22 Support for manufacturing a strip based on polycrystalline sillicon

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0550159A FR2880900B1 (en) 2005-01-19 2005-01-19 SENSIVELY PLANAR EXTENSION CARRIER FOR THE MANUFACTURE OF A POLYCRYSTALLINE SILICON STRIP
FR0550159 2005-01-19

Publications (1)

Publication Number Publication Date
WO2006077298A1 true WO2006077298A1 (en) 2006-07-27

Family

ID=34953725

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FR2005/051142 WO2006077298A1 (en) 2005-01-19 2005-12-22 Support for manufacturing a strip based on polycrystalline silicon

Country Status (3)

Country Link
EP (1) EP1874983A1 (en)
FR (1) FR2880900B1 (en)
WO (1) WO2006077298A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4383130A (en) * 1981-05-04 1983-05-10 Alpha Solarco Inc. Solar energy cell and method of manufacture
EP0079567A2 (en) * 1981-11-13 1983-05-25 COMPAGNIE GENERALE D'ELECTRICITE Société anonyme dite: Process for making polycrystalline silicon films for solar cells
US5441577A (en) * 1991-03-07 1995-08-15 Mitsubishi Denki Kabushiki Kaisha Thin film solar cell and production method therefor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4383130A (en) * 1981-05-04 1983-05-10 Alpha Solarco Inc. Solar energy cell and method of manufacture
EP0079567A2 (en) * 1981-11-13 1983-05-25 COMPAGNIE GENERALE D'ELECTRICITE Société anonyme dite: Process for making polycrystalline silicon films for solar cells
US5441577A (en) * 1991-03-07 1995-08-15 Mitsubishi Denki Kabushiki Kaisha Thin film solar cell and production method therefor

Also Published As

Publication number Publication date
EP1874983A1 (en) 2008-01-09
FR2880900B1 (en) 2007-04-13
FR2880900A1 (en) 2006-07-21

Similar Documents

Publication Publication Date Title
EP1114446B1 (en) Method for producing a thin membrane
FR2804245A1 (en) Method for the formation of a thin crystalline layer containing silicon at high productivity and low cost
EP1268884B1 (en) Method and device for making substrates
EP1618612A1 (en) Sintered semiconductor material
WO1995031825A1 (en) Method for production of a structure with a low level of dislocations and having an oxide layer buried in a semiconductor substrate
EP2867942B1 (en) Lithium-ion battery with a cathode with variable porosity and corresponding method
FR3007892A1 (en) METHOD FOR TRANSFERRING A THIN LAYER WITH THERMAL ENERGY SUPPLY TO A FRAGILIZED AREA VIA AN INDUCTIVE LAYER
FR2460545A1 (en) PROCESS FOR PREPARING LAYERS OF HG1-XCDXTE
EP1846957B1 (en) Method for the production of photovoltaic cells
EP2979306A1 (en) Process for manufacturing a multi-junction structure for a photovoltaic cell
WO2006077298A1 (en) Support for manufacturing a strip based on polycrystalline silicon
EP1900012A1 (en) Highly oxygen-sensitive silicon layer and method for obtaining same
FR2724487A1 (en) COMPOSITE STRUCTURE WITH A SEMICONDUCTOR LAYER ARRANGED ON A DIAMOND LAYER AND / OR A DIAMOND-LIKE LAYER AND METHOD FOR THE PRODUCTION THEREOF
FR2973157A1 (en) METHOD FOR PRODUCING ISOLATES OF AT LEAST PARTIALLY RELAXED STRAINED MATERIAL
WO2010026343A1 (en) Method for preparing a self-supporting crystallized silicon thin film
FR2848334A1 (en) Multi-layer structure production of semiconductor materials with different mesh parameters comprises epitaxy of thin film on support substrate and adhesion on target substrate
WO2006100301A1 (en) Method of producing a hetero-structure comprising at least one thick layer of semiconductor material
EP3577257A1 (en) Process for manufacturing a two-dimensional film of hexagonal crystalline structure
WO2023084173A1 (en) Method for preparing a carrier substrate provided with a charge-trapping layer
EP2566996B1 (en) Carbon tape intended to receive a layer of a semiconductor material
WO2023084168A1 (en) Method for preparing a support substrate provided with a charge-trapping layer
FR2849268A1 (en) Fabricating collapsible substrate for electronic, opto-electronic and optic applications, by forming adhesive interface with migration of an atomic species to produce a gaseous phase at the interface
WO2010076422A1 (en) Method for assembling two substrates in a vacuum at a negative temperature, and machine for implementing said method
FR3038393A1 (en) FIBER OF CRYSTALLINE MATERIAL AND METHOD OF MANUFACTURING THE SAME
WO2014177809A1 (en) Formation of a i-iii-vi2 semiconductor layer by heat treatment and chalcogenization of an i‑iii metallic precursor

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 2005825984

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE

WWP Wipo information: published in national office

Ref document number: 2005825984

Country of ref document: EP