Silicon block, method for producing the same, crucible of transparent or opaque fused silica suited for performing the method, and method for the production thereof

US9828691B2 · kind B2 · utility

Assignee

• HERAEUS QUARZGLAS GMBH & CO. KG · DE

Inventors

• Christian Schenk · Ingelheim am Rhein, DE
• Gerrit Scheich · Seligenstadt, DE
• Nils Christian Nielsen · Göllheim, DE
• Walter Lehmann · Leipzig, DE
• Bernhard Freudenberg · Coburg, DE
• Kaspars DADZIS · Freiberg, DE
• Sandra Nadolny · Freiberg, DE
• Franziska Wolny · Dresden, DE
• Gerd Fischer · Hannover, DE

Key dates

• Filing date: Aug 4, 2015
• Grant date: Nov 28, 2017
• Expiry date: Oct 31, 2035

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03B2201/03
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A method for producing a solar crucible includes providing a crucible base body of transparent or opaque fused silica having an inner wall, providing a dispersion containing amorphous SiO2 particles, applying a SiO2-containing slip layer to at least a part of the inner wall by using the dispersion, drying the slip layer to form a SiO2-containing grain layer and thermally densifying the SiO2-containing grain layer to form a diffusion barrier layer. The dispersion contains a dispersion liquid and amorphous SiO2 particles that form a coarse fraction and a fine fraction with SiO2 nanoparticles. The weight percentage of the SiO2 nanoparticles based on the solids content of the dispersion is in the range between 2 and 15% by weight. The SiO2-containing grain layer is thermally densified into the diffusion barrier layer through the heating up of the silicon in the crystal growing process.