MONOCRYSTAL FOR MANUFACTURE OF DISKS IN SURFACE ACOUSTIC WAVE DEVICES AND METHOD OF OBTAINING MONOCRYSTAL Russian patent published in 2001 - IPC

FIELD: manufacture of acoustic electronic frequency-selective surface acoustic and volume acoustic units. SUBSTANCE: used as monocrystal for manufacture of disks is monocrystal of lanthanum gallium niobate or lanthanum gallium tantalate at diameter of 86 to 110 mm in direction of thermostable cut obtained by loading monocrystal charge which was synthesized preliminarily and was obtained by building-up synthesized polycrystal charge in form of profiled pellets and produced by sintering of respective oxides in space between inner walls of alundum crucible whose diameter is equal to diameter of iridium crucible for growing the monocrystal and alundum tube in its central portion assembled in form of hollow cylinder with crystal mount passing along its central axis with seed; inner surface of alundum crucible and outer surface of alundum tube are coated platinum; protective atmosphere is formed in two stages: in melting the charge, only gaseous argon is used and oxygen is added after melting, seed crystal oriented in direction of thermostable cut is brought in contact with surface of melt and monocrystal is pulled from it. EFFECT: improved quality of large-sized monocrystals; facilitated procedure of synthesis; rational use of raw materials. 4 cl