A method of creating thin wafers of single crystal silicon, sapphire and similar materials, wherein an ingot of single crystalline material, or a ribbon of single crystalline material is cleaved, in a plane parallel to a surface, with laser light focused to a line in the desired plane of cleavage, near the growing cleavage furrow. The light is of a wavelength that the material is transparent to, but for which the material has strong two- or three-photon absorption. Consequently the light is not appreciably absorbed until it reached the desired focal line. The light is presented in an extremely short pulse, which heats and expands the material at the line focus, before the heat can be dissipated. This expansion creates tangential stresses around the focal line. These stresses are designed to be precisely normal to the growing cleavage furrow. Therefore the stresses are able to induce cleavage in the desired plane, without inducing cleavage in other possible cleavage planes that may happen to intersect with the growing cleavage edge. In this way, extremely thin wafers and ribbon shaped wafers can be produced, with extremely high quality cleaved faces. Methods of initiating the cleavage furrow and separating the cleaved wafer from the rest of the crystal are also discussed.

A substrate 10 contains a first layer L1 and a second layer L2 that are stacked on one another, the first layer L1 contains crystalline AlN and an additive element, the second layer L2 contains crystalline α-alumina, the additive element is at least one selected from the group consisting of rare earth elements, alkaline earth elements, and alkali metal elements, the thickness of the first layer L1 is 5 to 600 nm, RC(002) is a rocking curve of diffracted X-rays originating from a (002) plane of AlN, RC(002) is measured by an ω-scan of the surface S.sub.L1 of the first layer L1, the half width of RC(002) is 0° to 0.4°, RC(100) is a rocking curve of diffracted X-rays originating from a (100) plane of AlN, RC(100) is measured by a ϕ-scan of the surface S.sub.L1 of the first layer L1, and the half width of RC(100) is 0° to 0.8°.

A device for producing a tubular single crystal comprises a crucible, a heating means, a die disposed in the crucible, having an annular slit, and a pulling-up means. The upper surface of the die includes an upward slope that increases in height from the annular slit to an inner diameter side and an outer diameter side, respectively, progressing away from the annular slit, wherein the maximum height of the slope on the inner diameter side (H1) is greater than the maximum height of the slope on the outer diameter side (H2) and the difference (H1−H2) is 0.1 mm or more and less than 7.5 mm.

A device for producing a tubular single crystal comprises a crucible, a heating means, a die disposed in the crucible, having an annular slit, and a pulling-up means. The upper surface of the die includes an upward slope that increases in height from the annular slit to an inner diameter side and an outer diameter side, respectively, progressing away from the annular slit, wherein the maximum height of the slope on the inner diameter side (H1) is greater than the maximum height of the slope on the outer diameter side (H2) and the difference (H1−H2) is 0.1 mm or more and less than 7.5 mm.

An apparatus for growing a crystal includes a growth chamber and a melt chamber thermally isolated from the growth chamber. The growth chamber includes: a growth crucible configured to contain a liquid melt; and a die located in the growth crucible, the die having a die opening and one or more capillaries extending from within the growth crucible toward the die opening. The melt chamber includes: a melt crucible configured to receive feedstock material; and at least one heating element positioned within the melt chamber relative to the melt crucible to melt the feedstock material within the melt crucible to form the liquid melt. The apparatus also includes at least one capillary conveyor in fluid communication with the melt crucible and the growth crucible to transport the liquid melt from the melt crucible to the growth crucible.

An apparatus for growing a crystal includes a growth chamber and a melt chamber thermally isolated from the growth chamber. The growth chamber includes: a growth crucible configured to contain a liquid melt; and a die located in the growth crucible, the die having a die opening and one or more capillaries extending from within the growth crucible toward the die opening. The melt chamber includes: a melt crucible configured to receive feedstock material; and at least one heating element positioned within the melt chamber relative to the melt crucible to melt the feedstock material within the melt crucible to form the liquid melt. The apparatus also includes at least one capillary conveyor in fluid communication with the melt crucible and the growth crucible to transport the liquid melt from the melt crucible to the growth crucible.

A heat exchange device for a single crystal furnace is provided, including a heat exchanger on which an inner chamber for heat exchange defined in a shape of circular truncated cone is formed. A convex portion is defined by a chamber wall of the inner chamber for heat exchange partially projecting along a radial direction of the inner chamber for heat exchange, the convex portion extends along a direction of an axis of the inner chamber for heat exchange, and a minimum distance between an end away from the chamber wall of the inner chamber for heat exchange of the convex portion and the axis of the inner chamber for heat exchange is denoted as L, which is greater than or equal to a minimum radius of a cross section of the inner chamber for heat exchange.

A seeding method for crystal growth comprising: a first seeding step: rotating a crucible with a first rotation speed to grow the crystal to a first length; a second seeding step: gradually increasing the rotation speed of the crucible from the first rotation speed to a second rotation speed, and growing the crystal to a second length; a third seeding step: rotating the crucible with the second rotation speed to growing the crystal to a predicted length. By separating the seeding stage to three steps and gradually increasing the rotation speed in the second step of the crucible, the silicon melt convection is enhanced and the temperature at center of the silicon melt is kept to be not lower than the starting temperature of the seeding. Thereby, the removal of dislocation within the seed crystal can be increased, and the growth problems such as broken or polycrystallization can be prevented.

A die for growing a single crystal by an Edge-defined Film-fed Growth (EFG) technique includes a first outer die plate; a second outer die plate; and at least one central die plate positioned between the first outer die plate and the second outer die plate such that at least two capillaries are formed between the first outer die plate and the second outer die plate. First ends of the first outer die plate and the second outer die plate have a slope extending away from at least one of the at least two capillaries to form a growth interface at a top of the die. Second ends of the first outer die plate and the second outer die plate are immersed in a raw material melt provided in a crucible. The raw material melt is configured to travel to the growth interface by capillary flow of the raw material melt through the at least two capillaries.

The present invention relates to an apparatus for growing crystals. The apparatus comprises a chamber and a crucible being arranged in a heatable accommodation space of the chamber, wherein the crucible comprises an inner volume which is configured for growing crystals inside. The crucible comprises a bottom from which respective side walls extend to a top section of the crucible. The crucible comprises at least one a deposition section which is configured for attaching a seed crystal, wherein the deposition section is formed on at least one of the side wall and the top section of the crucible.