Growth of doped crystals
AssigneeThe Harshaw Chemical Company
InventorCarl F. Swinehart
Life of this patent
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Abstract
Large, doped crystal ingots are grown in a Stockbarger furnace from a melt of an alkali metal or alkaline earth metal salt using very slow oscillation (1 - 2 cycles per minute) of the ingot through a small arc of 5.degree. -20.degree. to produce an ingot having a more even distribution of dopant and an absence of open boundaries between macrocrystals within the ingot.
Claims6
In the Stockbarger method of growing inorganic alkali metal or alkaline earth metal salt crystal ingots of at least two inches in diameter and containing a plurality of crystal domains or macrocrystal components, from a stratified melt of the same containing up to 1.5% of a dissolved dopant, the improvement comprising slowly moving, with variable velocity, the solidified crystal with respect to the melt about a vertical axis at a rate that is adequate to maintain an even distribution of the dopant in the melt at the interface, but that is not sufficient to disturb the temperature gradient in the melt.
Dependencies are inferred from the claim text.