Abstract:
A method of growing a ribbon crystal provides a crucible containing molten material and passes string through the molten material to grow the ribbon crystal. The method further directs gas flow around the ribbon crystal such that the gas flows down along the ribbon crystal toward the crucible.
Abstract:
A method and apparatus for growing a semiconductor crystal include pulling the semiconductor crystal from melt at a pull speed and modulating the pull speed by combining a periodic pull speed with an average speed. The modulation of the pull speed allows in-situ determination of characteristic temperature gradients in the melt and in the crystal during crystal formation. The temperature gradients may be used to control relevant process parameters that affect morphological stability or intrinsic material properties in the finished crystal such as for instance the target pull speed of the crystal or the melt gap, which determines the thermal gradient in the crystal during growth.
Abstract:
Methods and apparatus for concurrent growth of multiple crystalline ribbons from a single crucible employ meniscus shapers to facilitate continuous growth of discrete and substantially flat crystalline ribbons having controlled width.
Abstract:
An apparatus for growing hollow crystalline bodies by the EFG process, comprising an EFG die having a top surface shaped for growing a hollow crystalline body having a cross-sectional configuration in the shape of a polygon having n faces, and a radiation shield adjacent to and surrounded by the top end surface of the die, characterized in that the shield has an inner edge defining a similar polygon with n sides, and the inner edge of the shield is notched so that the spacing between the n faces and the n sides is greatest between the central portions of the n faces and the n sides, whereby the greater spacing at the central portions helps to reduce lateral temperature gradients in the crystalline body that is grown by use of the die.
Abstract:
An improved susceptor for a crucible/die assembly for growing tubular crystalline structures by the EFG process is provided. The crucible/die assembly comprises a die having a substantially polygonally-shaped top end surface for supporting a film of silicon feed material that is replenished from a melt in the crucible through capillary action. A hollow crystalline body is grown from the film of silicon material on the top end surface of the die. The heat susceptor is made of graphite or similar material, and has a peripheral configuration similar to that of the die. Further, the upper surface of the heat susceptor has a central land and a plurality of circumferentially-spaced upwardly extending projections. The central land thermally contacts a central portion of the lower surface of the crucible/die, and the projections thermally contact the lower surface of the crucible/die at its corners, whereby a temperature distribution is provided that permits growth of hollow bodies having more nearly constant thickness walls.
Abstract:
A rutile single crystal with no grain boundaries of large inclination is obtained by an EFG crystal growth process wherein a die provided with slits is incorporated in a feed melt 2 to deliver up the melt through the slits until it reaches the upper face of the die, thereby obtaining a single crystal conforming in configuration to the die by pulling growth.
Abstract:
A method and apparatus for producing a manganese-zinc ferrite single crystal using a local liquid pool formation which involves melting of a starting material in a crucible and lowering of the temperature of crucible to make the resultant melt maintain form three phase regions of an upper liquid pool region, an intermediate semi-rigid region and a lower solid region. A pair of heaters are disposed at the upper and side wall portions of crucible and controlled differently from each other so that the formed lower solid region extends at its peripheral portion throughout the inner surface of the side wall portion of the crucible, thereby minimizing the contact of the formed upper liquid pool region with the whole inner surface of the crucible. For monitoring respective temperatures of various portions in the crucible to control the heaters, there are provided thermocouples which includes a thermocouple for the crystal drawing port member, a thermocouple for the upper portion of crucible, a thermocouple for the upper portion of the side wall of crucible and a thermocouple for the lower portion of crucible.
Abstract:
An improved furnace is provided for growing crystalline bodies from a melt. The improved furnace is characterized by a door assembly which is remotely controlled and is arranged so as to selectively shut off or permit communication between an access port in the furnace enclosure and a hot zone within that enclosure. The invention is especially adapted to facilitate use of crystal growing cartridges of the type disclosed in U.S. Pat. No. 4,118,197.
Abstract:
A METHOD AND APPARATUS IS DESCRIBED FOR HORIZONTALLY PULLING CRYSTAL RIBBONS FROM A MELT PARALLEL TO THE MELT SURFACE. THE HEAT OF CRYSTALLIZATION IS SELECTIVELY REMOVED FROM ONE END OF A SEED CRYSTAL BY A HEAT ABSORBING MEANS PERPENDICULAR TO THE MELT SURFACE. MEANS ARE PROVIDED TO APPROPRIATELY SUPPRESS NET LOSS OF THE HEAT OF FUSION FROM THE BALANCE OF THE SEED IN CONTACT WITH THE MELT TO CONTROL THE THICKNESS OF THE RESULTANT RIBBON.