92 results about "Czochralski process" patented technology

A weir is extended vertically to define an optimal annular gap between the top of the weir and the underside of a super-adjacent heat shield. The annular gap provides a high velocity stream of argon gas to be directed from the growth region to the melt region to substantially eliminate the transport of airborne particles from the melt region to the growth region. The tall weir may be configured as a modular, reusable weir extension supportably engaged with an outer (and/or inner) weir.

An improved system based on the Czochralski process for continuous growth of a single crystal ingot comprises a low aspect ratio, large diameter, and substantially flat crucible, including an optional weir surrounding the crystal. The low aspect ratio crucible substantially eliminates convection currents and reduces oxygen content in a finished single crystal silicon ingot. A separate level controlled silicon pre-melting chamber provides a continuous source of molten silicon to the growth crucible advantageously eliminating the need for vertical travel and a crucible raising system during the crystal pulling process. A plurality of heaters beneath the crucible establish corresponding thermal zones across the melt. Thermal output of the heaters is individually controlled for providing an optimal thermal distribution across the melt and at the crystal/melt interface for improved crystal growth. Multiple crystal pulling chambers are provided for continuous processing and high throughput.

In a method of producing a lithium niobate substrate by the use of a lithium niobate crystal grown by the Czochralski process, the lithium niobate crystal is heat-treated at a temperature of from 300° C. or more to less than 500° C. in the state the lithium niobate crystal is buried in a powder constituted of at least one element selected from the group consisting of Al, Ti, Si, Ca, Mg and C, or in the state the lithium niobate crystal is held in a container constituted of at least one element selected from the group consisting of Al, Ti, Si, Ca, Mg and C.

A silicon wafer produced from a silicon single crystal ingot grown by Czochralski process is subjected to rapid heating/cooling thermal process at a maximum temperature (T₁) of 1300° C. or more, but less than 1380° C. in an oxidizing gas atmosphere having an oxygen partial pressure of 20% or more, but less than 100%. The silicon wafer according to the invention has, in a defect-free region (DZ layer) including at least a device active region of the silicon wafer, a high oxygen concentration region having a concentration of oxygen solid solution of 0.7×10¹⁸ atoms/cm³ or more and at the same time, the defect-free region contains interstitial silicon in supersaturated state.

A silica glass crucible includes a stable, bubble-free inner layer and an opaque outer layer, both layers demonstrating reduced bubble growth during a Czochralski process. When used in the CZ process, little volume change is observed in the crucible wall, and the crucible has little influence on melt level. The present crucible is especially suited for slow silicon ingot pulling with reduced crystalline defects. The fusion process of the present invention controls the dynamic gas balance at the fusion front where formed grain is melted to dense fused silica.

A method and system for use in combination with a crystal growing apparatus for growing a monocrystalline ingot according to a Czochralski process. The crystal growing apparatus has a heated crucible including a semiconductor melt from which the ingot is pulled. The ingot is grown on a seed crystal pulled from the melt. A time varying external magnetic field is imposed on the melt during pulling of the ingot. The magnetic field is selectively adjusted to produce pumping forces in the melt to control a melt flow velocity while the ingot is being pulled from the melt.

In a Czochralski process for growing single crystal silicon ingots, a system is provided for adding solid material to the liquid silicon during crystal growth for the purpose of directly controlling the latent heat of fusion with respect to a crystal melt interface. In contrast to the standard method for controlling power to the crucible heater, the present system has been found to be much more effective for controlling melt temperature in the crucible, especially in heavily insulated systems. The system provides the advantage of reducing the electric power required to operate a Czochralski grower, while increasing the speed with which the melt temperature can be raised or lowered in a controlled manner.

The invention discloses a method for controlling a sapphire seeding form of a Kyropoulos method. The method comprises that an aluminum oxide raw material is placed in a mono-crystal furnace crucible, seed crystal is installed on a seed crystal rod, a vacuum system and a heating system are started, the voltage of the heating system is adjusted, so that the aluminum oxide raw material is melted completely, a convectional stable state of a melt surface is achieved, and the deviation distance of a cold core of a liquid level and a geometric centre of the crucible is less than 20mm; the seed crystal position is adjusted slowly, then the seed crystal is close to the melt liquid surface gradually, simultaneously, the working voltage of the heating system is adjusted, and the melting of the seed crystal is avoided; preheating is performed for 30 minutes at a position of 2-5mm from the lower end portion of the seed crystal to the melt liquid surface; and the seed crystal is rotated through a traditional Czochralski process, the working voltage of the heating system is adjusted, the diameter of the end portion of crystallization is controlled to be less than 50mm and shouldering is started to be performed after the cold core is coated by the end portion of the crystallization. By the aid of the method, the form of the end portion of the crystallization can be well controlled, the operation is simple, and the success ratio and the yield of the seed crystal are improved.

A system for growing silicon crystals that facilitates controlling a shape of a melt-solid interface is described. The crystal growing system includes a heated crucible including a semiconductor melt from which a monocrystalline ingot is grown according to a Czochralski process. The ingot is grown on a seed crystal pulled from the melt. The method includes applying an unbalanced cusped magnetic field to the melt, and rotating the ingot and the crucible in the same direction while the ingot is being pulled from the melt.

The invention discloses a method and a device for improving the uniformity of the axial resistivity of czochralski monocrystalline silicon. The device comprises a doping agent container, a mass flowmeter, an electromagnetic valve and a conveying pipe. The method comprises the following steps of (1), preparation before the start of the pulling of monocrystalline silicon; (2), melting of a polycrystalline-silicon raw material; (3), seeding; (4), shouldering; (5), shoulder rotation; (6), diameter equaling; (7), ending. The method and the device for improving the uniformity of the axial resistivity of the czochralski monocrystalline silicon have the advantages that (1), a conventional doping way in a czochralski process is changed, the uniformity of an axial doping element in the monocrystalline silicon is improved, and further, the uniformity of the axial resistivity is improved; (2), the device provided by the invention is simple in structure and is convenient to operate.

The invention discloses a processing technology for preparing single crystal silicon by the Czochralski method, which comprises the following steps: necking growth: when the temperature of the silicon melt is stabilized to a certain temperature, the seed crystal is immersed in the silicon melt, and the seed crystal is Increase the pulling speed at a certain rate to reduce the diameter of the seed crystal to 3-7mm; shoulder growth: after the necking growth is completed, reduce the crucible temperature and pulling speed, adjust the crucible rotation speed and crystal rotation speed, and increase the crystal to the required diameter; equal-diameter growth: after the shoulder growth is completed, adjust the crucible temperature, pulling speed, crucible rotation speed and crystal rotation speed, so that the diameter of the ingot is maintained between plus and minus 2mm; the present invention adds pure boron to the single crystal silicon raw material, The mass ratio of pure boron to monocrystalline silicon raw materials is 5%-15%, so that the resistivity of monocrystalline silicon can reach 300Ω/CM, and the radial uniformity of resistivity is within 3%; reduce the oxygen content in silicon melt It effectively inhibits the entry of oxygen from the silicon melt into the silicon crystal, improves work efficiency, and reduces the oxygen content of the silicon crystal.

The present invention discloses one kind of magnetic material with bi-directional shape memory effect and its monocrystal preparing process. The magnetic monocrystal material has the chemical expression of MnxNiyGaz, where x is 37-55, y is 20-38, z is 20-30, x+y+z=100, x, y and z are atom percentage content. The monocrystal preparing process includes setting prepared material in crucible and Czochralski process of growing the magnet MnxNiyGaz monocrystal. The magnetic monocrystal material has its martensitic transformation temperature regulated via altering the Mn, Ni and Ga ratio, and may have martensitic starting point regulated in 36-350 K and Curie temperature in 140-330 deg.c as requirement. In addition, the present invention uses conventional equipment, has low cost and is easy industrial application.