HYDROTHERMAL CRYSTAL GROWING PROCESS

摘要

Large single crystals of berlinite are grown onto seed crystals by maintaining the crystals at a fixed elevated temperature in a pressure vessel containing a nutrient of coarse berlinite crystalline powder, held at a fixed lower temperature, and a mixture of hydrochloric and phosphoric acids. Because berlinite shows retrograde solubility in the acid mixture, the nutrient goes into solution, and berlinite deposits on the higher-temperature growing crystal. Large single crystals of alpha-gallium orthophosphate may be grown using the same apparatus and a similar process. The resultant crystals may be cut into wafers useful in surface acoustic wave devices.