A seed crystal holder according to the present invention for growing a crystal by a solution method, and that includes a seed crystal made of silicon carbide; a holding member above the seed crystal; a bonding agent configured to fix the seed crystal and the holding member; and a sheet member made of carbon which is interposed in the bonding agent in a thickness direction, and which has an outer periphery smaller than an outer periphery of the seed crystal in a plan view.

A crystal has a diameter of 1 cm or more and shows a strongest peak in cathode luminescent spectrum at a wavelength of 360 nm in correspondence to a band edge.

A crystal growth apparatus comprises a reaction vessel holding a melt mixture containing an alkali metal and a group III metal, a gas supplying apparatus supplying a nitrogen source gas to a vessel space exposed to the melt mixture inside the reaction vessel, a heating unit heating the melt mixture to a crystal growth temperature, and a support unit supporting a seed crystal of a group III nitride crystal inside the melt mixture.

A system and method provides a piezoelectric stack arrangement for reduced driving voltage while maintaining a driving level for active piezoelectric materials. A stack arrangement of d.sub.36 shear mode <011>single crystals of both air X-cut and Y-cut 1:45 (20) arrangement are bonded with discrete conductive pillars to form a shear crystal stack. The bonding area between the neighboring crystal parts is minimized. The bonding pillars are positioned at less than a total surface are of the single crystal forming the stack. The stack fabrication is facilitated with a precision assembly system, where crystal parts are placed to desired locations on an assembly fixture for alignment following the preset operation steps. With the reduced clamping effect from bonding due to lower surface coverage of the discrete conductive pillars, such a piezoelectric d.sub.36 shear crystal stack exhibits a reduced driving voltage while maintaining a driving level and substantial and surprisingly improved performance.

In one embodiment, a sheet production apparatus comprises a vessel configured to hold a melt of a material. A cooling plate is disposed proximate the melt and is configured to form a sheet of the material on the melt. A first gas jet is configured to direct a gas toward an edge of the vessel. A sheet of a material is translated horizontally on a surface of the melt and the sheet is removed from the melt. The first gas jet may be directed at the meniscus and may stabilize this meniscus or increase local pressure within the meniscus.

A method for preventing molten material breach in a crystal growth apparatus includes providing a chamber of the crystal growth apparatus which is coated with a ceramic material. The chamber can be coated on an interior surface to prevent damage to the chamber itself, which is made of steel, and to prevent steam explosions in the water-cooled chamber. Ceramic blanket layers also can be provided over the coated interior surface of the chamber. As a result, it is possible to produce high quality crystalline products while minimizing the hazards and costs in the event of a spill of molten material.

A semiconductor template having a top surface aligned along a (100) crystallographic orientation plane and an inverted pyramidal cavity defined by a plurality of walls aligned along a (111) crystallographic orientation plane. A method for manufacturing a semiconductor template by selectively removing silicon material from a silicon template to form a top surface aligned along a (100) crystallographic plane of the silicon template and a plurality of walls defining an inverted pyramidal cavity each aligned along a (111) crystallographic plane of the silicon template.