Device for growing of the rectangular monocrystals of sapphire

FIELD: chemical industry; methods of growing of the rectangular monocrystals of sapphire.

SUBSTANCE: the invention is pertaining to the technology of growing from melts of the monocrystals of sapphire and may be used at production of the volumetric crystals with the crystallographic orientation along the axis <1010> or <1120>. The device contains the vacuum chamber with the installed in it the crucible, the rectangular shaper, the heater assembled out of the lamellas fixed on the current leads, the screens, the rod with the seed-crystal holder and the systems adjusting the hoisting speed of the seed crystal and power of the heater. The crucible, the generatrix of the lamellas and the deflector have the rectangular form, between the bottom of the crucible and the shaper there is the spacing, the altitude of the walls of the shaper exceeds the altitude of the crucible. The wall of the shaper in their upper part are made slit along the ribs and bent off along the slits in the direction of the walls of the chamber, the shaper rests on the upper edge of walls of the crucible by its slit parts. The technical result of the invention consists in the rise of the output of the single crystals up to 60 % due to reaching of integrity of the geometrical shape of the crystal with the crystallographic orientation along the axis <1010> or <1120> and acceleration of the growing process.

EFFECT: the invention ensures the increased output of the suitable single crystals up to 60 % due to reaching the integrity of the geometrical shape of the crystal with the crystallographic orientation along the axis <1010> or <1120> and acceleration of the growing process.

5 cl, 2 dwg

 

The device relates to a process of growth from melts sapphire crystal and can be used to obtain bulk crystals with crystallographic orientation along the axis <1010> or <1120>.

A device for growing single crystals of sapphire, containing installed in a vacuum chamber heater, crucible composed of an alloy of molybdenum and tungsten with the shaper, structurally, heat shields, speed regulation system of lifting the seed crystal and the power of the heater, in which the crucible has an insert made of tungsten and a basket in the form of tungsten rods, the upper ends of which protrude over the edge of the crucible and curved outwards. The purpose of the basket and liner is to increase the service life of structural elements (Patent RF №2227822 published in 2004).

A well-known shaper for growing monocrystalline ribbons sapphire, the upper ends of which side of the capillary gap is made with a bevel angle of 10-40° degrees to the vertical axis (USSR Author's certificate No. 839324, published in 1991). The shaper provides improved structural perfection of the obtained tapes, but in its present form cannot be used to obtain larger crystals.

The closest to the problem at hand, the aggregate sign is in and the achieved result is a device for growing single crystals of sapphire on Nametkina, containing a vacuum chamber, in which is installed a heater in the form of slats attached to the current leads, the crucible former, made in the form of rectangular prisms, aligned to the seed crystal, stem with structuralism, heat shields, one of which is installed around the crucible is otrajatelem. Off camera systems have been installed to control the speed of ascent of the crystal and the power of the heater. The crucible and the reflector are cylindrical in shape, forming lamellae has the shape of a circle (Eurasian patent №003419, published in 2002).

A disadvantage of the known devices is the inability to obtain a crystal in the form of the integral in the form of a parallelepiped due to the contraction in its upper part, resulting in loss of product. The maximum yield of crystals is 50%. In addition, the disadvantage of this device is the duration carried out in its growing process, component for a single crystal of about 180 hours.

The technical result of the invention is to increase the yield of single crystals up to 60% at the expense of achieving the integrity of the geometric shape of the crystal with crystallographic orientation axis <1010> or <1102> and speeding up the process. This result is particularly relevant for the production of single crystals of sapphire specified the crystallographer is political orientation, with the high cost.

This technical result is achieved in that the device for growing shaped bulk single crystals of sapphire, containing a vacuum chamber defined therein a crucible, rectangular shaper, heater, assembled from strips, attached to the current leads, screens, stem with structuralism and speed regulation system of lifting the seed crystal and the power of the heater, crucible, forming lamellae are rectangular in shape, between the bottom of the crucible and the shaper has a gap, the height of the walls shaper exceeds the height of the crucible wall shaper in the upper part of the cut made along the edges and bent at the grooves in the direction of the chamber walls, the shaper is based on the top edge the walls of the crucible cut parts.

In addition, the length of the slot edges of the wall is 15-20% of the length of the ribs, the angle of the cut parts relative to the vertical axis of the crucible is 25-35°, shaper made with additional support in the form of pins located in the middle of the lower edge or edges of the shaper, the clearance between the bottom of the crucible and the bottom edge of the shaper is 0,015-0,025, and the distance between the walls of the crucible and shaper - 0,05-0,06 from the height of the crucible, respectively.

p> The device and its fragment shown in figure 1 and 2.

The device shown in figure 1, consists of a vacuum chamber (1), which has a rectangular crucible (2), rectangular shaper (3), the heater (4) forming a rectangular blades, a rod with a fixed structuralism (5), screens (6), the reflector rectangular shape (7), the current and speed regulation system of lifting the seed crystal and the power of the heater (not shown).

Figure 2 shows the crucible with the shaper.

The operation of the device

In a vacuum chamber (1) establish the crucible (2) shaper (3) coaxially with the heater (4). Loaded into the crucible initial charge, for example, in the form of crushed pieces of sapphire or granules of alumina, set on structurale (5) the seed crystal in the form of a rectangular prism with crystallographic orientation along the axis that is selected depending on the single crystal from which the orientation is planned to grow (for single crystal oriented along the axis <1010> is a rectangular prism with the same orientation along the axis, the side faces of which are pairwise orientation of <0001> and <1102>; for a single crystal with orientation axis <1120> is a rectangular prism with the same orientation along the axis, the side faces of which are pairwise orientation 0001> and <1010>). Seal is the Amer and create a vacuum to (1-5)× 10-5mm Hg Feeding power to the heater (4), are warming up to a temperature of 2100°To receive the melt and keep it for 2-3 hours for homogenization. Screens (6) and the reflector (7) is used to create a uniform thermal field and protect the camera from overheating. Then reduce the temperature to 2050°and lower the seed crystal before contact with the melt. After soaking for 2-4 minutes monocrystal raise at a rate of 0.5-0.6 mm/min After 20-30 minutes, lifting the seed crystal is terminated. Further razresevanje crystal to the walls of the shaper and depth of the crucible is provided an analog control system capacity of the heater. Provided by the invention is the implementation of the walls shaper provides a convex solidification front in relation to the melt. After completion of the crystallization of the melt supplied power is uniformly reduced to zero within 12-16 hours, the single crystal within 6-8 hours is cooled to a temperature less than 100°C, after which it is unloaded from the chamber.

Rectangular elements of the device (the crucible, shaper, heater and reflector) in combination with convex solidification front, provided by the execution of the former, allows to increase the yield of single crystals up to 60-65% by achieving a whole is in the surrounding area of the geometric shape rectangular crystal and accelerate the growth process. Even for large-size single crystals of sapphire reduction in the duration of cultivation in comparison with the prototype is not less than 30 hours.

1. Device for growing shaped bulk single crystals of sapphire, containing a vacuum chamber defined therein a crucible, rectangular shaper, heater, assembled from strips, attached to the current leads, reflector, screens, stem with structuralism and speed regulation system of lifting the seed crystal and the power of the heater, wherein the crucible, forming of the blades and the reflector are rectangular in shape, between the bottom of the crucible and the shaper has a gap, the height of the walls shaper exceeds the height of the crucible wall shaper in the upper part of the cut made along the edges and bent at the grooves in the direction of the chamber walls, the shaper is based on the top edge the walls of the crucible cut parts.

2. The device according to claim 1, characterized in that the length of the slot edges of the wall is 15-20% of the length of the ribs.

3. The device according to claim 1, characterized in that the angle of cut of the parts relative to the vertical axis of the crucible is 25-35°.

4. The device according to claim 1, wherein the shaper is made with additional support in the form of pins, the location is the R in the middle of the lower edge or edges of the shaper.

5. The device according to claim 1, characterized in that the clearance between the bottom of the crucible and the bottom edge of the shaper is 0,015-0,025, and the distance between the walls of the crucible and shaper 0,05-0,06 from the height of the crucible, respectively.



 

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7 cl, 2 dwg

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2 cl, 2 dwg, 2 ex

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1 dwg 1 o

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