Process stages on the grower and link for main grower units with required process parameters

 Prepare raw material  Prepare machine and hot zone  Creation vacuum  Melting  Seeding  Growth  Detachment  Annealing  Unloading ingot

Prepare raw material Verneuil stones scrap Compacted powder (density over 3.3 g/cm^3) Purity % Check purity under UV lamp (Hg) Size: mm Layer by layer dense loading

Prepare machine and hot zone

Creation vacuum Diffusion pump Lock Vacuum gauage APG Electromagnetic valve

Vacuum parameters 1 Initial vacuum 1*10 -2 Pa 2Melting 5*10 -4 Pa 3Annealing 5*10 -5 Pa

Melting 5 cm melt Crucible material Equilibrium gas concentration in melt Mo x 10 W x 1.1 Ir No change

Reaction in Al 2 O 3 Al 2 O 3  Al 2 O+AlO Al 2 O 3  Al 2 O+2O Al 2 O 3  Al 2 O 2 +O AlO  Al+O AlO 2  Al+2O Al 2 O  AlO+Al Al 2 O  2Al+O Al 2 O 2  Al 2 O+O Al 2 O 2  2Al+2O Al 2 O 2  2AlO 2O  O 2

Adjusting temperature field Black seed  t melt ~ 100°C  =2.88 g/cm 3

Control parameters  Voltage on heater fluctuation 1 mV in the range 5-12 V  Voltage decreasing rate 5-15 mV/hour  Pulling rate mm/hour, accuracy 1%  Accuracy of load measurement 1 g when load100 kg.  Temperature change 1 deg/hour when water flow cubic meter/hour and water pressure 4-6 bars

Adjust melt temperature for seeding Over froozen melt Normal island seed

Seeding Seed Convection line Island Over heated Normal

Formation constrictions  Heat removal from grown ingot – to provide ingot temperature lower then crucible walls  Decreasing dislocations density  Decrease inner stress  Symmetrical growth

Shouldering Seed Crystal

Animation of the temperature along the melt free surface Before seedingSeedingShouldering

Not symmetrical field HORN

Melt temperature fluctuations «Blinds» Overheated melt- bubbles accepted by solid interface due to temperature fluctuations «Central cord» too cold melt or too fast growth speed

Ingots profile mm/hour mm/hour

 After touch of ingot with crucible bottom to increase pulling up rate to mm/hour

Cycle example- capacity

Position of seed

Weight fluctuation

Weight

Annealing Voltage-hours

Unloading ingot

Prepare machine for next cycle  Remove foreign material from crystallizer shields and heater and apply vacuum cleaner for crystallizer  Clean elements of hot zone with rectified alcohol  Remove and clean windows  Clean washer with rectified alcohol

Optical properties Transmission As grown (b, d) and after X-ray 4 hours (с, e)

X-ray diffraction диафрагма: b – 5 мм, c –2мм, d-1 мм, e-0,2 мм, f-0,1 мм