Compartmentalized sump and gas flow system for silicon ribbon production

An apparatus for forming a crystalline ribbon grown on a surface of a melt comprising:

• an inner chamber defining a process gas inlet, an exhaust outlet, and a silicon ribbon exit;
• a crucible configured to hold a melt, wherein the crucible is disposed in a volume of the inner chamber;
• a cold initializer facing an exposed surface of the melt, wherein the cold initializer is disposed in a volume of the inner chamber;
• a process gas feed in fluid communication with the process gas inlet;
• an outer chamber, wherein the outer chamber surrounds at least part of the inner chamber and defines an opening for the process gas feed and a sump inlet;
• a plurality of heaters disposed in a sump region between an interior surface of the outer chamber and an exterior surface of the inner chamber;
• and
• a sump gas feed in fluid communication with the sump inlet, wherein the sump gas feed is configured to deliver a sump gas to the sump region.