PREPARATION METHOD FOR SINGLE CRYSTAL OF HIGH-PURITY QUARTZ

摘要

PURPOSE: A preparation method of a crystal of high-purity by disposing a seed crystal horizontally in an autoclave and hydrothermal-etching the crystal with a gradient of negative temperature in a heat rising step is provided which can minimize the formation of a cluster. CONSTITUTION: A method for making a high-purity quartz crystal comprises: (a)disposing a seed crystal horizontally in an autoclave and hydrothermal-etching the crystal with a gradient of negative temperature in a heat rising step in which the temperature in a crystal growing part is raised to 10-20 deg.C more than in a dissolving part when the temperature in a crystal growing part reaches 200 deg.C in the heating rising step. The compound is useful as a high-purity quartz oscillator, a surface acoustic element, and an optical low pass filter.