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

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Presentation on theme: "Process stages on the grower and link for main grower units with required process parameters."— Presentation transcript:

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

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

3 Prepare raw material Verneuil stones scrap Compacted powder (density over 3.3 g/cm^3) Purity 99.998% Check purity under UV lamp (Hg) Size: 20-60 mm Layer by layer dense loading

4 Prepare machine and hot zone

5 Creation vacuum Diffusion pump Lock Vacuum gauage APG Electromagnetic valve

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

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

8 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

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

10 Control parameters  Voltage on heater fluctuation 1 mV in the range 5-12 V  Voltage decreasing rate 5-15 mV/hour  Pulling rate 0.1-0.6 mm/hour, accuracy 1%  Accuracy of load measurement 1 g when load100 kg.  Temperature change 1 deg/hour when water flow 3.5-4.5 cubic meter/hour and water pressure 4-6 bars

11 Adjust melt temperature for seeding Over froozen melt Normal island seed

12 Seeding Seed Convection line Island Over heated Normal

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

14 Shouldering Seed Crystal

15 Animation of the temperature along the melt free surface Before seedingSeedingShouldering

16 Not symmetrical field HORN

17 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

18 Ingots profile 0.3-0.4 mm/hour 0.6-0.7 mm/hour

19  After touch of ingot with crucible bottom to increase pulling up rate to 0.5..0.6 mm/hour

20 Cycle example- capacity

21 Position of seed

22 Weight fluctuation

23 Weight

24 Annealing Voltage-hours

25 Unloading ingot

26 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

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

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


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