A method of fabricating a poly-crystalline silicon ingot includes: (a) loading a nucleation promotion layer onto a bottom of a mold; (b) providing a silicon source on the nucleation promotion layer in the mold; (c) heating the mold until the silicon source is melted into a silicon melt completely; (d) controlling at least one thermal control parameter regarding the silicon melt continually to enable the silicon melt to nucleate on the nucleation promotion layer such that a plurality of silicon grains grow in the vertical direction; (e) controlling the at least one thermal control parameter to enable the plurality of the silicon grains to continuously grow with an average grain size increasing progressively in the vertical direction until entirety of the silicon melt is solidified to obtain the poly-crystalline silicon ingot, wherein the nucleation promotion layer is loaded by spreading a plurality of mono-Si particles over the bottom of the mold.

Methods and systems for low etch pit density 6 inch semi-insulating gallium arsenide wafers may include a semi-insulating gallium arsenide single crystal wafer having a diameter of 6 inches or greater without intentional dopants for reducing dislocation density, an etch pit density of less than 1000 cm.sup.?2, and a resistivity of 1?10.sup.7 ?-cm or more. The wafer may have an optical absorption of less than 5 cm.sup.?1 less than 4 cm.sup.?1 or less than 3 cm.sup.?1 at 940 nm wavelength. The wafer may have a carrier mobility of 3000 cm.sup.2/V-sec or higher. The wafer may have a thickness of 500 ?m or greater. Electronic devices may be formed on a first surface of the wafer. The wafer may have a carrier concentration of 1.1?10.sup.7 cm.sup.?3 or less.

To provide a single crystal production apparatus that is capable of prolonging the lifetime of a heater, and capable of reducing the cost. A single crystal production apparatus of the present invention is the single crystal production apparatus which produces a single crystal of a metal oxide in an oxidative atmosphere, containing: a base body; a cylindrical furnace body having heat resistance disposed above the base body; a lid member occluding the furnace body; a heater disposed inside the furnace body; a high frequency coil heating the heater through high frequency induction heating; and a crucible heated with the heater, the heater containing a Pt-based alloy and having a zirconia coating on an overall surface of the heater.

Disclosed is a method of growing a zirconia single crystal that has excellent physical properties free from low-temperature degradation and thus enables precise machining, the method including raw material preparation, raw material charging, raw material melting, melt soaking stage, seed production, and single crystal growth.

A poly-crystalline silicon ingot having a bottom and defining a vertical direction includes a plurality of silicon grains grown in the vertical direction, in which the plurality of the silicon grains have at least three crystal orientations; and a nucleation promotion layer comprising a plurality of chips and chunks of poly-crystalline silicon on the bottom, wherein the poly-crystalline silicon ingot has a defect density at a height ranging from about 150 mm to about 250 mm of the poly-crystalline silicon ingot that is less than 15%.

A crystal growth apparatus includes a crucible, a heating device, a thermal insulation cover, and a driving device. The crucible contains materials to be melted, wherein the heating device heats the crucible to melt the materials; the thermal insulation cover is provided upon the materials, wherein the thermal insulation cover includes a main body, which has a bottom surface facing an interior of the crucible, and a insulating member being provided at the main body; the driving device moves the thermal insulation cover towards or away from the materials, whereby, the thermal insulation cover effectively blocks heat conduction and heat convection, which prevents thermal energy from escaping out of the crucible.

A substrate, in particular intended for contact with liquid silicon, wherein it is at least partially surface-coated with a multilayer coating formed by: at least one layer, known as the adhesion layer, contiguous with the substrate, having an open porosity of at least 30%, and formed of a material comprising silica and silicon nitride, said material having a silica content of between 10 wt.-% and 55 wt.-% in relation to the total weight thereof; and a layer different from the adhesion layer, known as the release layer, located on the surface of the adhesion layer and formed of a material including silica and silicon nitride, said material having a silica content of between 2 wt.-% and 10 wt.-% in relation to the total weight thereof.

A crystal growth furnace comprising a crucible containing at least feedstock material and a liquid-cooled heat exchanger that is vertically movable beneath the crucible to extract heat from it to promote the growth of a crystalline ingot is disclosed. The liquid-cooled heat exchanger comprises a heat extraction bulb made of high thermal conductivity material that is vertically movable into thermal communication with the crucible to extract heat from the crucible using a liquid coolant. A liquid-cooled heat exchanger enclosed in a sealed tubular outer jacket is also disclosed as is a method for producing a crystalline ingot using a vertically movable liquid-cooled heat exchanger.

A method for manufacturing a polycrystalline silicon ingot includes steps of: a) melting a silicon material in a container disposed in a thermal field to form a molten silicon; b) controlling the thermal field to provide heat to the molten silicon from above the container and to solidify a portion of the molten silicon contacting a base part and at least a portion of a wall part proximate to the base part of the container to form a solid silicon crystalline isolation layer; and c) controlling the thermal field to continuously provide heat to the rest of the molten silicon from above the container and to solidify the rest of the molten silicon gradually from a bottom to a top of the rest of the molten silicon to form a polycrystalline silicon ingot.

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.