An apparatus (10) for producing an SiC single crystal is used in the solution growth includes a seed shaft (28) and a crucible (14). The seed shaft (28) has a lower end surface (28S) to which an SiC seed crystal (32) is to be attached. The crucible (14) holds an SiC solution (15). The seed shaft (28) includes a cylinder part (28A), a bottom part (28B), and a low heat conductive member (28C). The bottom part (28B) is located at the lower end of the cylinder part (28A) and has the lower end surface (28S). The low heat conductive member (28C) is arranged on the upper surface of the bottom part (28B) and has a thermal conductivity lower than that of the bottom part (28B). This production apparatus can make the temperature within the crystal growth surface of the SiC seed crystal less liable to vary.

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.

An improved system based on the Czochralski process for continuous growth of a single crystal ingot comprises a low aspect ratio, large diameter, and substantially flat crucible, including an optional weir surrounding the crystal. The low aspect ratio crucible substantially eliminates convection currents and reduces oxygen content in a finished single crystal silicon ingot. A separate level controlled silicon pre-melting chamber provides a continuous source of molten silicon to the growth crucible advantageously eliminating the need for vertical travel and a crucible raising system during the crystal pulling process. A plurality of heaters beneath the crucible establish corresponding thermal zones across the melt. Thermal output of the heaters is individually controlled for providing an optimal thermal distribution across the melt and at the crystal/melt interface for improved crystal growth. Multiple crystal pulling chambers are provided for continuous processing and high throughput.

The passivation of a nonlinear optical crystal for use in an inspection tool includes growing a nonlinear optical crystal in the presence of at least one of fluorine, a fluoride ion and a fluoride-containing compound, mechanically preparing the nonlinear optical crystal, performing an annealing process on the nonlinear optical crystal and exposing the nonlinear optical crystal to a hydrogen-containing or deuterium-containing passivating gas.

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.

The bulk polysilicon deposition rate of a Siemens method CVD reactor system having a power supply configured for deposition on a solid rod silicon filament of a specified diameter and length is increased by installing a high surface area silicon filament in the CVD reactor in lieu of the specified solid rod filament, the high surface area filament being dimensionally configured such that it can be used in place of the solid rod filament without reconfiguring or replacing the reactor power supply. The high surface area filament can be tubular, flat, or shaped with radial fins. Existing reactors thereby require only adaptation or replacement of filament supports to be adapted for use of the high surface area filament. The high surface area filament can be grown from silicon melt using the EFG method, so as to maintain a cross-sectional shape within a tolerance of +/10%.

A stirring apparatus of an ingot casting furnace includes a rotating shaft and at least one fin. The fin is provided onto the rotating shaft, and has a first edge, a second edge of unequal length provided correspondingly, and a third edge connecting the first and the second edges. The rotating shaft can be driven to rotate, which consequently drives the at least one fin to stir materials in a crucible. The length of the first edge is different from that of the second edge in order for the materials in the crucible can be mixed with dopants more uniformly during the stirring process to produce ingots of stable quality.

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.

A method and process for the production of bulk polysilicon by chemical vapor deposition (CVD) where conventional silicon slim rods commonly used in Siemens-type reactors are replaced with shaped silicon filaments of similar electrical properties but larger surface areas, such as silicon tubes, ribbons, and other shaped cross sections. Silicon containing gases, such as chlorosilane or silane, are decomposed and form a silicon deposit on the hot surfaces of the filaments The larger starting surface areas of these filaments ensures a higher production rate without changing the reactor size, and without increasing the number and length of the filaments. Existing reactors need only the adaptation or replacement of filament supports to use the new filaments. The filaments are grown from silicon melt by Edge-defined, Film-fed Growth (EFG) method. This also enables the doping of the filaments and simplification of power supplies for new reactors.

Disclosed is a single-crystal growth apparatus including a chamber, a crucible provided in the chamber and configured to accommodate a melt that is a raw material for single-crystal growth, a heater disposed between the crucible and a side wall of the chamber and heating the crucible, and a crucible screen disposed on an upper end of the crucible, and the crucible screen has a bending member reflecting a radiant heat generated from the melt in the crucible to inside wall of the crucible.