METHOD FOR PRODUCING POLYCRYSATLLINE SILICON

• Main Authors: POPP, FRIEDRICH, HERTLEIN, HARALD
• Format: Patent
• Language: English
• Published: 24.11.2021
• Subjects: CHEMISTRY; COMPOUNDS THEREOF; INORGANIC CHEMISTRY; METALLURGY; NON-METALLIC ELEMENTS

THE INVENTION RELATES TO A METHOD FOR PRODUCING GRANULATED POLYCRYSTALLINE SILICON IN WHICH POLYCRYSTALLINE SILICON IS DEPOSITED ON CARRIER BODIES HEATED BY THE DIRECT PASSAGE OF A CURRENT WHICH ENABLES POLYCRYSTALLINE SILICON RODS TO BE PRODUCED. SAID CARRIER BODIES ARE MAINTAINED ON A BASE PLATE OF A REACTOR AND ARE SUPPLIED WITH A CURRENT BY ELECTRODES, THE DEPOSIT OF POLYCRYSTALLINE SILICON IS STOPPED WHEN THE POLYCRYSTALLINE SILICON RODS HAVE REACHED A DESIRED END DIAMETER. SAID POLYCRYSTALLINE SILICON RODS ARE THEN REMOVED FROM THE REACTOR AND THE REACTOR IS EQUIPPED WITH NEW CARRIER BODIES IN ORDER TO PRODUCE ADDITIONAL POLYCRYSTALLINE SILICON RODS. THE BASE PLATE OF THE REACTOR IS CLEANED AFTER THE EXTRACTION OF THE POLYCRYSTALLINE SILICON RODS FROM THE REACTOR AND PRIOR TO THE EQUIPPING OF THE REACTOR WITH NEW CARRIER BODIES. THE INVENTION IS CHARACTERISED IN THAT THE CLEANING OF THE BASE PLATE TAKES PLACE IN AT LEAST TWO CLEANING STEPS DURING WHICH AT LEAST TWO CLEANING AGENTS WITH DIFFERENT AGGREGATE STATES ARE USED.