The present invention makes clear and defines a congruent composition of a langasite-based oxide, and establishes a method of manufacturing a crystal by any desired composition of AE.sub.3ME.sub.1+a(Ga.sub.1-xAl.sub.x).sub.3+bSi.sub.2+cO.sub.14 (AE is an alkaline-earth metal, ME is Nb or Ta, 0x1, 0.5<a0 or 0<a<0.5, 0.5<b0 or 0<b0.5, and 0.5<c0 or 0<c<0.5, excluding a=b=c=0). This makes it possible to suppress the formation of an impurity, and improve the yield and crystal manufacturing rate. The raw material is a raw material mixture prepared by mixing an alkaline-earth metal or its carbonate or oxide, Nb or Ta or its oxide, Ga or its oxide, Al or its oxide, and Si or its oxide.

Ingot puller apparatus for preparing a single crystal silicon ingot by the Czochralski method are disclosed. The ingot puller apparatus includes a heat shield. The heat shield has a leg segment that includes a void (i.e., an open space without insulation) disposed in the leg segment. The heat shield may also include insulation partially within the heat shield.

Ingot puller apparatus for preparing a single crystal silicon ingot by the Czochralski method are disclosed. The ingot puller apparatus includes a heat shield. The heat shield has a leg segment that includes a void (i.e., an open space without insulation) disposed in the leg segment. The heat shield may also include insulation partially within the heat shield.

The present invention provides a metal wire rod composed of iridium or an iridium alloy, wherein the number of crystal grains on any cross-section in a longitudinal direction is 2 to 20 per 0.25 mm.sup.2, and the Vickers hardness at any part is 200 Hv or more and less than 400 Hv. The iridium wire rod is a material which is produced by a -PD method, and has low residual stress and which has a small change in the number of crystal grains and hardness even when heated to a temperature equal to or higher than a recrystallization temperature (1200 C. to 1500 C.). The metal wire rod of the present invention is excellent in oxidative consumption resistance under a high-temperature atmosphere, and mechanical properties.

The present invention provides a metal wire rod composed of iridium or an iridium alloy, wherein the number of crystal grains on any cross-section in a longitudinal direction is 2 to 20 per 0.25 mm.sup.2, and the Vickers hardness at any part is 200 Hv or more and less than 400 Hv. The iridium wire rod is a material which is produced by a -PD method, and has low residual stress and which has a small change in the number of crystal grains and hardness even when heated to a temperature equal to or higher than a recrystallization temperature (1200 C. to 1500 C.). The metal wire rod of the present invention is excellent in oxidative consumption resistance under a high-temperature atmosphere, and mechanical properties.

A method for producing a mono-crystalline sheet includes providing at least two aperture elements forming a gap in between; providing a molten alloy including silicon in the gap; providing a gaseous precursor medium comprising silicon in the vicinity of the molten alloy; providing a silicon nucleation crystal in the vicinity of the molten alloy; and bringing in contact said silicon nucleation crystal and the molten alloy. A device for producing a mono-crystalline sheet includes at least two aperture elements at a predetermined distance from each other, thereby forming a gap, and being adapted to be heated for holding a molten alloy including silicon by surface tension in the gap between the aperture elements; a precursor gas supply supplies a gaseous precursor medium comprising silicon in the vicinity of the molten alloy; and a positioning device for holding and moving a nucleation crystal in the vicinity of the molten alloy.

A method for producing a mono-crystalline sheet includes providing at least two aperture elements forming a gap in between; providing a molten alloy including silicon in the gap; providing a gaseous precursor medium comprising silicon in the vicinity of the molten alloy; providing a silicon nucleation crystal in the vicinity of the molten alloy; and bringing in contact said silicon nucleation crystal and the molten alloy. A device for producing a mono-crystalline sheet includes at least two aperture elements at a predetermined distance from each other, thereby forming a gap, and being adapted to be heated for holding a molten alloy including silicon by surface tension in the gap between the aperture elements; a precursor gas supply supplies a gaseous precursor medium comprising silicon in the vicinity of the molten alloy; and a positioning device for holding and moving a nucleation crystal in the vicinity of the molten alloy.

Provided is a raw material supply unit comprising: a main body having a space into which raw material is filled; a barrier for dividing the main body into two or more areas in the longitudinal direction; a rod extending from above the main body into the interior of same; and a valve, connected to the rod, for covering or exposing the lower portion of the main body, wherein the bottom surface of the main body has a step.

Provided is a raw material supply unit comprising: a main body having a space into which raw material is filled; a barrier for dividing the main body into two or more areas in the longitudinal direction; a rod extending from above the main body into the interior of same; and a valve, connected to the rod, for covering or exposing the lower portion of the main body, wherein the bottom surface of the main body has a step.

A single crystal manufacturing apparatus to grow a single crystal upward from a seed crystal, the apparatus including an insulated space thermally insulated from a space outside the single crystal manufacturing apparatus, an induction heating coil placed outside the insulated space, a thermal insulation plate that divides the insulated space into a first space including a crystal growth region to grow the single crystal and a second space above the first space and includes a hole above the crystal growth region, a heating element that is placed in the second space and generates heat by induction heating using the induction heating coil to heat the inside of the insulated space, and a support shaft to vertically movably support the seed crystal from below.