Method and apparatus for crystal growth
AssigneeEvergreen Solar, Inc.
InventorEmanuel Michael Sachs
Life of this patent
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Abstract
A method and apparatus for growing a crystalline or poly-crystalline body from a melt is described, wherein the melt is retained by capillary attachment to edge features of a mesa crucible. The boundary profile of the resulting melt surface results in an effect which induces a ribbon grown from the surface of the melt to grow as a flat body. Further, the size of the melt pool is substantially reduced by bringing these edges close to the ribbon, thereby reducing the materials cost and electric power cost associated with the process.
Claims22
An apparatus for forming a crystalline ribbon, comprising:
- a crucible including:
- a crucible body having a top surface supporting substantially all of a melt of a source material for forming the crystalline ribbon;
- a pair of side walls extending downward from opposing edges of the top surface, the edges formed to retain substantially all of the melt by capillary attachment to the top surface of the crucible;
- and
- a puller for drawing the crystalline ribbon from the melt and away from the crucible body and top surface thereof.
An apparatus for controlling temperature of a crucible while forming a crystalline ribbon, the apparatus comprising:
- a crucible disposed within a furnace, the crucible including:
- a crucible body having a top surface supporting substantially all of a melt of a source material for forming the crystalline ribbon, and
- a pair of side walls extending downward from opposing edges of the top surface, the edges formed to retain substantially all of the melt by capillary attachment to the top surface of the crucible;
- a puller for drawing the crystalline ribbon from the melt and away from the crucible body and top surface thereof;
- an insulator comprising movable elements disposed along the crucible;
- and means for moving the moveable elements of the insulator relative to the crucible to create controlled heats leaks from the furnace.
An apparatus for replenishing a melt of a source material on a crucible, the apparatus comprising:
- a crucible body having a top surface supporting substantially all of a melt of a source material for forming the crystalline ribbon;
- a pair of side walls extending downward from opposing edges of the top surface, the edges formed to retain substantially all of the melt by capillary attachment to the top surface of the crucible;
- a puller for drawing the crystalline ribbon from the melt and away from the crucible body and top surface thereof;
- a feeder positioned at a distance from the crucible, the feeder movable in a first direction and a second direction along the crucible;
- and
- means for vibrating the feeder during motion in at least one of the first direction and the second direction, such that a source material disposed within the feeder enters the melt during such motion.
An apparatus for forming a crystalline ribbon, the apparatus comprising:
- a crucible for retaining a melt having a boundary profile, the crucible having:
- a top surface supporting substantially all of the melt of the source material for forming a crystalline ribbon;
- and
- a pair of side walls extending downward from opposing edges of the top surface, the edges formed to retain substantially all of the melt by capillary attachment to the top surface of the crucible;
- and
- a puller for drawing the crystalline ribbon from the melt and away from the crucible body and top surface thereof, wherein at least a portion of the boundary profile is concave downward.
An apparatus for forming a crystalline ribbon, the apparatus comprising:
- a crucible for retaining a melt having a boundary profile, the crucible having:
- a top surface supporting substantially all of the melt of the source material for forming a crystalline ribbon;
- and
- a pair of side walls extending downward from opposing edges of the top surface, the edges formed to retain substantially all of the melt by capillary attachment to the top surface of the crucible;
- and
- a puller for drawing the crystalline ribbon from the melt and away from the crucible body and top surface thereof, thereby forming an inflection point in at least a portion of a cross-sectional boundary profile of the melt.
An apparatus for forming a crystalline ribbon, the apparatus comprising:
- a top surface supporting substantially all of the melt of the source material for forming a crystalline ribbon;
- and
- a pair of side walls extending downward from opposing edges of the top surface, the edges formed to retain substantially all of the melt by capillary attachment to the top surface of the crucible;
- and
- a puller for drawing the crystalline ribbon from the melt and away from the crucible body and top surface thereof, wherein a substantial portion of the melt is above the edges of the crucible.
A crucible comprising:
- a crucible body having a top surface supporting substantially all of a melt of a source material for forming a crystalline ribbon;
- and
- a pair of side walls extending downward from opposing edges of the top surface, the edges formed to retain substantially all of the melt by capillary attachment to the top surface of the crucible;
- and
- means for pulling the crystalline ribbon from the melt and away from the crucible body and top surface thereof.
Dependencies are inferred from the claim text.