Systems and methods are presented for efficient heating during production of corundum. One embodiment takes the form of a system for processing corundum including a first furnace and a second furnace. The first and second furnaces are sequentially arranged and heat from the first furnace is subsequently used to heat the second furnace.

The device forming a crucible for fabrication of crystalline material by directional solidification comprises a bottom and at least one side wall. The bottom presents a first portion having a first thermal resistance and a second portion having a second thermal resistance that is lower than the first thermal resistance. The second portion is designed to receive a seed for fabrication of the crystalline material. The bottom and side wall are at least partially formed by a tightly sealed part including at least one indentation participating in defining said first and second portions. The first portion is covered by a first anti-adherent layer having an additional first thermal resistance. The second portion may be covered by a second anti-adherent layer having an additional second thermal resistance that is lower than the first thermal resistance.

The crystallization system includes a crucible provided with a bottom and with side walls designed to contain the material to be solidified and a device for creating a main thermal gradient inside the crucible in a perpendicular direction to the bottom of the crucible. An additional inductive heating device is arranged at the level of the side walls of the crucible facing the liquid material and without overlapping with the solid phase. This additional inductive heating device is configured to heat a part of the crystalline material located in the vicinity of the triple contact line between the liquid material, the solidified material and the crucible so that the interface between the liquid material and the solidified material forms a convex meniscus in the vicinity of the triple contact line.

Methods and wafers for low etch pit density, low slip line density, and low strain indium phosphide are disclosed and may include an indium phosphide single crystal wafer having a diameter of 4 inches or greater, having a measured etch pit density of less than 500 cm.sup.?2, and having fewer than 5 dislocations or slip lines as measured by x-ray diffraction imaging. The wafer may have a measured etch pit density of 200 cm.sup.?2 or less, or 100 cm.sup.?2 or less, or 10 cm.sup.?2 or less. The wafer may have a diameter of 6 inches or greater. An area of the wafer with a measured etch pit density of zero may at least 80% of the total area of the surface. An area of the wafer with a measured etch pit density of zero may be at least 90% of the total area of the surface.

The present invention relates to a substrate-triggered single crystal superalloy directional solidification process, including: (1) preparing a single crystal substrate material having crystallographic characteristics that match crystallographic characteristics of the single crystal superalloy; (2) fabricating a single crystal substrate chilling plate using the obtained single crystal substrate material; and (3) applying the obtained single crystal substrate chilling plate in a directional solidification apparatus, and then preparing a single crystal alloy product by performing superalloy melting and directional solidification. Compared with grain selector method and seeding with grain selector method, in addition to control the crystallographic orientation of the single crystal superalloy precisely, the present invention could reduce the height of block and the whole mold through canceling the spiral grain selector, significantly improve the axial heat dissipation and temperature gradient at the solid-liquid interface, and then reduce the occurrence of freckles and stray grains near platform.

An apparatus for forming a crystalline sheet. The apparatus may include a crystallizer comprising a first gas channel and a second gas channel, wherein the first gas channel and second gas channel extend through the crystallizer to a lower surface of the crystallizer between an upstream edge and a downstream edge. The first gas channel may be disposed closer to the downstream edge than the second gas channel. A first gas source may be coupled to the first gas channel, where the first gas source comprises helium or hydrogen, and a second gas source may be coupled to the second gas channel, where the second gas source does not contain hydrogen or helium.

A method for recharging a crucible with polycrystalline silicon comprises adding flowable chips to a crucible used in a Czochralski-type process. Flowable chips are polycrystalline silicon particles made from polycrystalline silicon prepared by a chemical vapor deposition process, and flowable chips have a controlled particle size distribution, generally nonspherical morphology, low levels of bulk impurities, and low levels of surface impurities. Flowable chips can be added to the crucible using conventional feeder equipment, such as vibration feeder systems and canister feeder systems.

An advanced crucible support system is described that allows for greater heat flow to and from the bottom of a crucible, preferably while also preventing excessive heat from reaching a heat exchanger. In particular, a support base is described that includes a plurality of spaced crown features disposed on the support base plate. The crown features receive and vertically support the crucible and are spaced to support the crucible and to allow heat flow between the plurality of crown features. In doing so, a top surface of spaced crown features are in direct contact with the crucible.

A method of manufacturing a directionally solidified article of the present disclosure includes providing a collection of particulate material and additively manufacturing a first article with an outer wall from the particulate material. The outer wall defines at least part of a cavity. The cavity contains an amount of the particulate material. The method also includes encasing at least a portion of the first article with an outer member. The outer member defines an internal cavity that corresponds to the first article. The method further includes heating the outer member and the first article to melt the first article into a molten mass within the internal cavity of the outer member. Additionally, the method includes solidifying the molten mass along a predetermined solidification path within the outer member to form a second article that corresponds to at least a portion of the internal cavity of the outer member.

A container for silicon ingot fabrication and a manufacturing method thereof are provided. The method includes the following steps. A base layer made of quartz is provided in a chamber. A powder solution layer is coated over an inner surface of the base layer. The powder solution layer includes silicon nitride or carbon. The base layer having the powder solution layer coated thereon is heated to a temperature of 1000 C. to 1700 C. while a reaction gas is supplied into the chamber for 2 hours to 8 hours to form a barrier layer over the inner surface of the base layer. The barrier layer includes silicon oxynitride represented by Si.sub.xN.sub.yO.sub.z, 1x2, 1y2, and 0.1z1. Moreover, a method for manufacturing a crystalline silicon ingot is also provided.