国外蓝宝石晶体生长炉介绍

蓝宝石晶体生长炉介绍

“OMEGA” GROWER

Catalog

1. General view of assembled grower “Omega”.

2. Technical purpose of the grower “Omega”.

The grower is intended for growing sapphire single crystals with diameter up to 200 mm and length up to 200 mm and weight up to 20 kg by the Kyropoulos method. The method consists in heating the initial raw material (aluminum oxide) in a tungsten crucible up to its melting point 2050 oC or above and gradual decreasing the melt temperature to crystallize it on a special seed. The growth is conducted in an air-locked crystallizer having special thermoisolating shields, covers and heater with charged crucible inside.

3. Technical specifications of the grower “Omega”.

蓝宝石晶体生长炉介绍

The load distribution between the phases is to be as follows : Phase A – 250 A, phase B – 250 A, phase C – 20 A.

To start the operation it is necessary to supply the grower with:

- recirculated water of I category under the pressure of 0,4 0,05 MPa. - pure gaseous argon under the pressure of 0,06 MPa (0,6 kgf/cm2).

For arrangement of the grower at the plant the following is required:

- minimal working area (room) - 8 m2;

- self-flowing water disposal system located on the floor level;

- ground mat.

4. Basic elements and component parts of the grower and their brief technical description.

The grower “Omega” consists of the components listed in the table below:

The crystallizer of the grower includes a table with an operating furnace, exhaust unit, mechanisms for the rod motion and rotation, mechanism for manual rod positioning and lifting the upper cover of chamber, control desk, pressure and drain collectors, cooling system, system for letting argon into furnace.

The drive with the column fixed to it and the upper cover of the furnace can be

蓝宝石晶体生长炉介绍

The furnace (fig. 2) consists of operating chamber, the upper covers, current lead, heater, screen fixed to the crucible, shields fixed to the current lead through a pedestal insulator. The crucible is placed on a molybdenum support.

Chamber and covers are water-cooled all-metal welded constructions made of stainless steel.

Cover has the quartz sight glasses required to control the process of nucleation and crystal growing at the beginning. The controlled molybdenum blinds are to provide glass protection from thermal radiation. The current lead is intended for applying current to the heater. It consists of two copper current drives.

Fig. 2. Crystallizer (operating furnace).

To cool the lead and copper ring of the heater, water goes to an internal cavity of the above mentioned drives.

Vacuum sealing of the current drives fixed to the cover with the split rings and insulating bush is carried out with a rubber gasket forming geometric connection when the nuts are tightened.

Fig. 3. Column.

蓝宝石晶体生长炉介绍

The column (fig. 3) mounted on the crystallizer is designed for rod operation and closing/opening the cover on the furnace.

The rod can execute translational movement with the rate of 0.03 x 10 –6 m/sec. (0.1 mm/h) to 7.5 x 10 –6 m/sec. (25 mm/h) and it also can rotate at frequency of 0.083 s-1 (5 rev. per min.) to 0.167 s-1 (10 rev. per min.). The rod is made of stainless steel but its head is made of copper to increase a convective heat exchange.

A tungsten crucible is placed into the furnace on a molybdenum support.

The heater of furnace is connected to a power board with a power line. The power board includes starting equipment, power transformer (fig. 4), power sensor and instrumentation.

Fig. 4. Transformer.

Fig. 5. Computer control board.

蓝宝石晶体生长炉介绍

Computer control board is placed on the crystallizer. It is to control, regulate, stabilize and program the settings of the growth process.

Fig. 6. Mechanical vacuum pump.

Mechanical vacuum pump is set behind crystallizer and is connected to its exhaust unit with a special hose.

Hydraulic system is intended for applying water to cool the furnace, rod and diffusion pump.

Water is applied to pressure collector from the water main through in-gate IG1 and actuator valve AV1. Then it goes to the separate cooling mains through the actuator gate and is emptied into drained collector. The gate IG7 is to cool diffusion pump.

The electric contact pressure gauge is fixed to pressure collector. It contains audible and light signaling that is switched on when collector has a water pressure less than required and when pressure is less than minimum the heater of furnace is switched off.

The actuator valve operates as throttling regulated valve and changes flow section depending on the instructed pressure which is applied from pressure collector. When in/outlet pressure of water is changed, the flow section of valve is also changed for keeping fixed nominal pressure ( 0.15 MPa) as constant into pressure collector.

Fig. 7. Diffusion pump and vacuum valves.

蓝宝石晶体生长炉介绍

Vacuum system is intended for pumping the furnace down up to residual pressure of 6 x 10 –3 Pa (5 x 10–5 mm Hg). It consists of mechanical pump P1, diffusion pump P2, thermionic rectifier valve VP4, vacuum valve VP5, solenoid valves V2, V3 and vacuum gauge VG 6, VG7.