Technique for the Growth of Compositionally Ungraded Single Crystals of Solid Solutions.
DEPARTMENT OF THE AIR FORCE WASHINGTON DC
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This invention describes a modified method of growing high purity, compositionally ungraded, single crystals of multicomponent solid solutions by the Czochralski, Kyropoulos, Bridgman or other related melt growth technqiue. In the method of this invention, the container or crucible used to contain the multicomponent crystal growing melt is fabricated from the higher melting point component of the multicompenent melt while lower melting point components are positioned within the crucible. The temperature of the crucible is then raised beyond the melting point of the lower melting point component to a temperature which is the exact melting point of the solid solution, or crystal alloy desired. This will dissolve an amount of the crucible material higher melting point compenent equal to the exact amount required to produce a solid solution having the desired composition. A seed is then introduced into the melt and normal crystal pulling is initiated resulting in the growth of a compositionally ungraded crystal having a uniform compositional content throughout its structure. Author