Process and apparatus for preparation of silicon crystals with reduced metal content

A crystal pulling apparatus for producing a silicon single crystal having a reduced amount of metal contamination grown by the Czochralski process, the apparatus comprising:

• a growth chamber;
• and
• a structural component disposed within the growth chamber, the component comprising graphite and having a protective layer covering the graphite, the protective layer comprising between about 0.01% and about 0.1% silicon and between about 99.9% and about 99.99% silicon carbide.

A process for controlling the contamination of a silicon single crystal ingot with metal associated with a graphite containing component used in a crystal pulling apparatus during the growth of the silicon crystal, the process comprising:

• coating a structural component constructed of graphite for use within a growth chamber of a crystal pulling apparatus with a first protective layer that covers the component and a second protective layer of silicon that covers the first protective layer;
• and
• pulling the silicon single crystal from a pool of molten silicon within the growth chamber.

A process for controlling the contamination of a silicon single crystal ingot with metal associated with a graphite containing component used in a crystal pulling apparatus during the growth of the silicon crystal, the process comprising:

• coating a structural component constructed of graphite for use within a growth chamber of a crystal pulling apparatus with a protective layer that covers the component, the protective layer comprising between about 0.01% and about 0.1% silicon and between about 99.9% and about 99.99% silicon carbide;
• and
• pulling the silicon single crystal from a pool of molten silicon with the growth chamber.

A component for use in a silicon single crystal pulling apparatus, the component comprising graphite and having a first protective layer covering the graphite and a second protective layer covering the first protective layer wherein the second protective layer is silicon.