Melt Growth Techniques
The “Top seeded solution growth (TSSG)” technique (with seed)
Crystallization may be accomplished with the help of seed crystals by dipping these crystals into a supersaturated solution. The procedure of the TSSG technique corresponds to that of the well-known Czochralski technique1 or the Nacken-Kyropoulos technique2 for melt-grown material.
The TSSG technique may be applied in two ways – the vertical temperature gradient transport method (using nutrient material) and the slow cooling method (in a supersaturated solution). The former is primarily used for compounds containing substituents or dopants while the latter is commonly used for pure compounds.
For an effective homogenization of the solution and a controlled growth process, optimized hydrodynamic conditions can be achieved by suitable seed rotation. Additionally, if the temperature gradient transport method is applied, it is necessary to pull the seed from the solution.[Melt Growth Techniques].
This method allows the growth of large, high-quality single crystals. Exposure of these crystals to any tension in the solidified solution is avoided by pulling them from the solution before the cooling process.
Usually the yield and quality of commercially applicable material obtained by TSSG crystallization is higher than that of spontaneously nucleated crystals grown by the bottom growth technique.
Continuous pulling of the seed crystal (located on the melt surface) during the growing process
Growth of a seed crystal dipped into the melt completely.