FLUX FOR CRYSTALLISING EPITAXIAL LAYERS OF FLUORITE AND METHOD FOR PRODUCING EPITAXIAL LAYERS OF FLUORITE Russian patent published in 2022 - IPC C30B19/02 C30B19/08 C30B19/12 C30B29/12 

FIELD: crystals.

SUBSTANCE: group of inventions relates to the field of optical materials science for use in photonics, optoelectronics, and in laser systems. Flux for crystallising epitaxial layers of fluorite, both pure and alloyed with rare earth ions by means of liquid phase epitaxy, constitutes a mixture of NaF and KF, at the following ratio of components, mol.%: NaF 0.58 to 0.84, KF 0.16 to 0.42. Method for producing epitaxial layers of fluorite, both pure and alloyed with rare earth ions by means of liquid phase epitaxy, includes the heating of the melt solution followed by crystallisation thereof on a fluorite seed under conditions of reduction in the temperature of the melt solution or under conditions of temperature gradient of the melt solution in the crystallisation zone, wherein the heating in the first case is continued until a temperature of 850 to 950 °C, in the second case 750 to 800 °C, and the crystallisation is performed from a melt solution with the composition CaF₂-NaF-KF using the above flux under conditions of reduction in the temperature of the melt solution at a rate of 1 °C/min or under conditions of temperature gradient of the melt solution in the crystallisation zone of 2 °C/cm.

EFFECT: proposed flux does not cause corrosion of container materials (platinum crucibles), is low-volatile, easily washed with water; as a result, the operating life of platinum crucibles is increased, and the process of producing epitaxial layers is safer and less toxic.

2 cl, 2 dwg, 2 tbl, 7 ex