DE19739881A1 - Production of crystalline silicon carbide - Google Patents
Production of crystalline silicon carbideInfo
- Publication number
- DE19739881A1 DE19739881A1 DE19739881A DE19739881A DE19739881A1 DE 19739881 A1 DE19739881 A1 DE 19739881A1 DE 19739881 A DE19739881 A DE 19739881A DE 19739881 A DE19739881 A DE 19739881A DE 19739881 A1 DE19739881 A1 DE 19739881A1
- Authority
- DE
- Germany
- Prior art keywords
- silicon carbide
- crystallized
- amorphous
- crystallization
- carbonitrides
- 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- Withdrawn
Links
Classifications
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- 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
- C30B29/10—Inorganic compounds or compositions
- C30B29/36—Carbides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/956—Silicon carbide
- C01B32/963—Preparation from compounds containing silicon
- C01B32/977—Preparation from organic compounds containing silicon
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- 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
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/02—Amorphous compounds
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/50—Solid solutions
- C01P2002/52—Solid solutions containing elements as dopants
- C01P2002/54—Solid solutions containing elements as dopants one element only
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Abstract
Description
Die vorliegende Erfindung betrifft ein neuartiges Verfahren zur Herstellung von kristallinem Siliciumcarbid aus Polysilylcarbodiimiden und Siliciumcarbonitriden. Das Siliciumcarbid kann rein dargestellt werden. Auch eine partielle Dotierung mit Kohlenstoff und Stickstoff ist möglich.The present invention relates to a novel method for producing crystalline silicon carbide from polysilylcarbodiimides and silicon carbonitrides. The silicon carbide can be represented purely. Partial doping with Carbon and nitrogen are possible.
Aus technischer Sicht ist Siliciumcarbid die bedeutendste Nichtoxidkeramik. Die weltweite Produktion liegt bei ca. 1×106 jato. Amorphe und kristalline Keramiken im ternären Si-C-N System können durch die Pyrolyse von Si-C-N-H-(O) Polymeren hergestellt werden. Polysilylcarbodiimide sind eine spezielle Polymerklasse dieses Systems.From a technical point of view, silicon carbide is the most important non-oxide ceramic. Worldwide production is around 1 × 10 6 t.Amorphous and crystalline ceramics in the ternary Si-CN system can be produced by pyrolysis of Si-CNH (O) polymers. Polysilylcarbodiimides are a special class of polymers in this system.
Die Darstellung der präkeramischen Si-C-N-H-(O) Polymere und der Polysilylcarbodiimide wird in mehreren Patenten beschrieben und ist nicht Gegenstand dieser Erfindung.The representation of the preceramic Si-C-N-H- (O) polymers and the Polysilylcarbodiimide is described in several patents and is not Subject of this invention.
Die deutsche Patentanmeldung 197 24 938. 8 vom 12.06.1997 beschreibt die Synthese von Siliciumcarbid aus Poly(methylsilsesquicarbodiimid). Dabei wird das Pyrolysat von Poly(methylsilsesquicarbodiimid) bei Temperaturen größer 1300°C in verschiedenen Atmosphären kristallisiert. Man erhält β-Siliciumcarbid. Dieser Darstellungsweg von Siliciumcarbid ist nicht Gegenstand dieser Erfindung.German patent application 197 24 938.8 of June 12, 1997 describes the Synthesis of silicon carbide from poly (methylsilsesquicarbodiimide). It will Pyrolysate of poly (methylsilsesquicarbodiimide) at temperatures above 1300 ° C crystallized in different atmospheres. Β-silicon carbide is obtained. This Representation of silicon carbide is not the subject of this invention.
Es wurde nun gefunden, daß alle Polysilylcarbodiimide der allgemeinen Formel [RSi(NCN)1.5]n zu Siliciumcarbid kristallisieren. Der Substituent R entspricht Alkyl-, Aryl- und Wasserstoff-Resten. Auch bifunktionelle Polysilylcarbodiimide der allgemeinen Formel [R0-1R'0-1Si-(X)m-SiR''0-1R'''0-1(NCN)1-3]n kristallisieren zu Siliciumcarbid. Hier sind die Substituenten R und R' ebenfalls Alkyl-, Aryl- und Wasserstoffreste, können aber auch weitere Carbodiimidbrücken darstellen. Das X repräsentiert ein kohlenwasserstoff- oder stickstoffhaltiges Brückenglied. Bei Disilanen ist m = 0.It has now been found that all polysilylcarbodiimides of the general formula [RSi (NCN) 1.5 ] n crystallize to form silicon carbide. The substituent R corresponds to alkyl, aryl and hydrogen radicals. Bifunctional polysilylcarbodiimides of the general formula [R 0-1 R ' 0-1 Si (X) m -SiR'' 0-1 R''' 0-1 (NCN) 1-3 ] n also crystallize to form silicon carbide. Here the substituents R and R 'are also alkyl, aryl and hydrogen radicals, but can also represent further carbodiimide bridges. The X represents a hydrocarbon or nitrogen-containing bridge member. For disilanes, m = 0.
Nach der Pyrolyse bei 1200°C ist bei den beschriebenen Polysilylcarbodiimiden das Verhältnis Silicium/Kohlenstoff ca. 1/1, unabhängig vom Substituenten R. Dieser spaltet sich teilweise bei der Pyrolyse ab oder wandert an der polymeren Hauptkette vom Silicium zum Kohlenstoff der Carbodiimidgruppe. Dies bedingt die Freisetzung von RH (bei Abspaltung des Restes R) und die Ausgasung von R-CN (bei Wanderung von R an der Hauptkette). Dieser Pyrolysemechanismus ist auch auf die substituierten bifunktionellen Polysilylcarbodiimide übertragbar und wurde noch nicht in der Literatur beschrieben.After pyrolysis at 1200 ° C is the described polysilylcarbodiimides the silicon / carbon ratio about 1/1, regardless of the substituent R. This partly splits off during pyrolysis or migrates to the polymer Main chain from silicon to carbon of the carbodiimide group. This requires the Release of RH (when the residue R is split off) and outgassing of R-CN (when moving from R to the main chain). This pyrolysis mechanism is too transferable to the substituted bifunctional polysilylcarbodiimides and became not yet described in the literature.
Des weiteren wurde gefunden, daß alle amorphen Siliciumcarbonitride der allgemeinen Formel Si1C0.8-1.2Nx bei Temperaturen oberhalb 1300°C zu Siliciumcarbid kristallisieren (vergl. Abb. 1). Diese Siliciumcarbonitride werden durch Pyrolyse von präkeramischen Si-C-N-H-(O) Polymeren hergestellt. Furthermore, it was found that all amorphous silicon carbonitrides of the general formula Si 1 C 0.8-1.2 N x crystallize to silicon carbide at temperatures above 1300 ° C. (cf. Fig. 1). These silicon carbonitrides are produced by pyrolysis of preceramic Si-CNH (O) polymers.
Die Kristallisation wird in einem Graphitofen bei Temperaturen größer 1300°C
durchgeführt. Die Aufheizrate beträgt jeweils 2°C/min, ist jedoch für die
Kristallisation von untergeordneter Rolle. Die Kristallisationsatmosphäre wurde
variiert (Stickstoff, Helium, Argon als Inertgas; Kohlenwasserstoffe, Ammoniak als
Reaktivgasatmosphäre). Die folgenden Kristallisationsbeispiele wurden in Argon
durchgeführt:
Crystallization is carried out in a graphite furnace at temperatures above 1300 ° C. The heating rate is 2 ° C / min in each case, but is of minor importance for the crystallization. The crystallization atmosphere was varied (nitrogen, helium, argon as an inert gas; hydrocarbons, ammonia as a reactive gas atmosphere). The following crystallization examples were carried out in argon:
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1. Bei der Pyrolyse von Poly(phenylsilsesquicarbodiimid) [C6H5Si(NCN)1.5]n bei
1200° C wird ein amorphes Pyrolysat der Zusammensetzung Si1C12N17 erhalten.
Die Kristallisation bei 1600°C ergibt Siliciumcarbid der Zusammensetzung Si1C0.95N0.05.1. In the pyrolysis of poly (phenylsilsesquicarbodiimide) [C 6 H 5 Si (NCN) 1.5 ] n at 1200 ° C., an amorphous pyrolysate with the composition Si 1 C 12 N 17 is obtained.
Crystallization at 1600 ° C. gives silicon carbide with the composition Si 1 C 0.95 N 0.05 . - 2. Bei der Pyrolyse von Poly(silsesquicarbodiimid) [HSi(NCN)1.5]n bei 1200°C wird ein amorphes Pyrolysat der Zusammensetzung Si1C0.8N1.9 erhalten. Die Kristallisation bei 1600°C ergibt Siliciumcarbid der Zusammensetzung Si1C1.05.2. When pyrolysis of poly (silsesquicarbodiimide) [HSi (NCN) 1.5 ] n at 1200 ° C., an amorphous pyrolysate with the composition Si 1 C 0.8 N 1.9 is obtained. Crystallization at 1600 ° C. gives silicon carbide with the composition Si 1 C 1.05 .
- 3. Bei der Pyrolyse von Poly(tert.-butylsilsesquicarbodiimid) [C4H9Si(NCN)1.5]n bei 1200°C wird ein amorphes Pyrolysat der Zusammensetzung Si1C1.1N1.4 erhalten. Die Kristallisation bei 1600°C ergibt Siliciumcarbid der Zusammensetzung Si1C0.95N0.05.3. In the pyrolysis of poly (tert-butylsilsesquicarbodiimide) [C 4 H 9 Si (NCN) 1.5 ] n at 1200 ° C., an amorphous pyrolysate with the composition Si 1 C 1.1 N 1.4 is obtained. Crystallization at 1600 ° C. gives silicon carbide with the composition Si 1 C 0.95 N 0.05 .
- 4. Bei der Pyrolyse von Poly(disilantricarbodiimid) [Si2(NCN)3]n bei 1200°C wird ein amorphes Pyrolysat der Zusammensetzung Si1C1.1N25 erhalten. Die Kristallisation bei 1600°C ergibt Siliciumcarbid der Zusammensetzung Si1C0.9N0.1. 4. When pyrolysis of poly (disilane tricarbodiimide) [Si 2 (NCN) 3 ] n at 1200 ° C., an amorphous pyrolysate with the composition Si 1 C 1.1 N 25 is obtained. Crystallization at 1600 ° C gives silicon carbide with the composition Si 1 C 0.9 N 0.1 .
- 5. Bei der Pyrolyse eines Polysilazangemisches bei 1200°C wird ein amorphes Pyrolysat der Zusammensetzung Si1C1.02N1.5 erhalten. Die Kristallisation bei 1600°C ergibt Siliciumcarbid der Zusammensetzung Si1N0.95N0.05.5. In the pyrolysis of a polysilazane mixture at 1200 ° C., an amorphous pyrolysate with the composition Si 1 C 1.02 N 1.5 is obtained. Crystallization at 1600 ° C. gives silicon carbide with the composition Si 1 N 0.95 N 0.05 .
Claims (12)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19739881A DE19739881A1 (en) | 1997-09-11 | 1997-09-11 | Production of crystalline silicon carbide |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19739881A DE19739881A1 (en) | 1997-09-11 | 1997-09-11 | Production of crystalline silicon carbide |
Publications (1)
Publication Number | Publication Date |
---|---|
DE19739881A1 true DE19739881A1 (en) | 1999-03-18 |
Family
ID=7841970
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19739881A Withdrawn DE19739881A1 (en) | 1997-09-11 | 1997-09-11 | Production of crystalline silicon carbide |
Country Status (1)
Country | Link |
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DE (1) | DE19739881A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1331743C (en) * | 2006-03-02 | 2007-08-15 | 浙江理工大学 | Process for preparing test tube brush type silicon carbide |
-
1997
- 1997-09-11 DE DE19739881A patent/DE19739881A1/en not_active Withdrawn
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1331743C (en) * | 2006-03-02 | 2007-08-15 | 浙江理工大学 | Process for preparing test tube brush type silicon carbide |
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Legal Events
Date | Code | Title | Description |
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8122 | Nonbinding interest in granting licences declared | ||
8139 | Disposal/non-payment of the annual fee |