Abstract: A filter for trapping, sterilizing, and decomposing organic matter, bacteria, viruses, and other harmful substances is provided at low cost and extremely high efficiency. A semiconductor material having a light emitting function is formed in the interior or on the surface of a porous ceramic material substrate by deposition from a suspension of semiconductor particles, and an electrode provided to serve as a filter. Voltage is applied so that ultraviolet light is emitted while a fluid is being filtered, and any harmful substances are filtered and simultaneously sterilized and decomposed.

Abstract: A large semiconductor crystal has a diameter of at least 6 inches and a low dislocation density of not more than 1×104 cm?2. The crystal is preferably a single crystal of GaAs, or one of CdTe, InAs, GaSb, Si or Ge, and may have a positive boron concentration of not more than 1×1016 cm?3 and a carbon concentration of 0.5×1015 cm?3 to 1.5×1015 cm?3 with a uniform concentration throughout the crystal. Such a crystal can form a very thin wafer with a low dislocation density. A special method and apparatus for producing such a crystal is also disclosed.

Abstract: The present invention provides a filter with which organic matter, bacteria, viruses, and other harmful substances can be trapped, and the trapped material can be sterilized and decomposed, at low cost and extremely high efficiency. A porous ceramic or metal is used as a substrate, and a porous semiconductor composed of a semiconductor material having a light emitting function is formed in the interior or on the surface of this substrate. An electrode is provided to this product to serve as a filter, voltage is applied so that ultraviolet light is emitted while a fluid is being filtered, and any harmful substances are filtered and simultaneously sterilized and decomposed. The porous semiconductor layer is preferably composed of columns grown perpendicular to the substrate plane, and has the function of emitting ultraviolet light with a wavelength of 400 nm or less.

Abstract: A large semiconductor crystal is produced by charging a raw material into a crucible in a reactor tube, sealing the reactor tube with a flange on an open end of the tube, pressurizing the interior of the tube to an elevated pressure with an inert gas, heating the tube with an externally arranged heater to melt the raw material to form a raw material melt in the crucible, and solidifying the raw material melt to grow the semiconductor crystal. A second raw material such as a group V element can be introduced as a vapor from a reservoir into the melt in the crucible to form a compound semiconductor material. The flange is sealed to the tube by an elastic seal member, of which the temperature is maintained below 400° C. throughout the process, to protect its elastic sealing properties.

Abstract: A large semiconductor crystal has a diameter of at least 6 inches and a low dislocation density of not more than 1×104 cm−2. The crystal is preferably a single crystal of GaAs, or one of CdTe, InAs, GaSb, Si or Ge, and may have a positive boron concentration of not more than 1×1016 cm−3 and a carbon concentration of 0.5×1015 cm−3 to 1.5×1015 cm−3 with a very uniform concentration throughout the crystal. Such a crystal can form a very thin wafer with a low dislocation density. A special method and apparatus for producing such a crystal is also disclosed.

Abstract: A large semiconductor crystal is produced by charging a raw material into a crucible in a reactor tube, sealing the reactor tube with a flange on an open end of the tube, pressurizing the interior of the tube to an elevated pressure with an inert gas, heating the tube with an externally arranged heater to melt the raw material to form a raw material melt in the crucible, and solidifying the raw material melt to grow the semiconductor crystal. A second raw material such as a group V element can be introduced as a vapor from a reservoir into the melt in the crucible to form a compound semiconductor material. The flange is sealed to the tube by an elastic seal member, of which the temperature is maintained below 400° C. throughout the process, to protect its elastic sealing properties.

Abstract: An apparatus and method of providing a large semiconductor crystal at a low cost are provided. The apparatus of producing a semiconductor crystal includes a reactor tube having an open end at least one end side, formed of any one material selected from the group consisting of silicon carbide, silicon nitride, aluminum nitride, and aluminum oxide, or of a composite material with any one material selected from the group consisting of silicon carbide, silicon nitride, aluminum nitride, boron nitride, aluminum oxide, magnesium oxide, mullite, and carbon as a base, and having an oxidation-proof or airtight film formed on the surface of the base, a kanthal heater arranged around the reactor tube in the atmosphere, a flange attached at the open end to seal the reactor tube, and a crucible mounted in the reactor tube to store material of a semiconductor crystal. The material stored in the crucible is heated and melted to form material melt. The material melt is solidified to grow a semiconductor crystal.

Abstract: A method of preparing a compound semiconductor crystal is able to dope the crystal with carbon with high reproducibility. The method includes the steps of sealing a carbon oxide gas of a predetermined partial pressure and a compound semiconductor material in a gas-impermeable airtight vessel, increasing the temperature of the vessel to melt the compound semiconductor material sealed in the vessel, and then decreasing the temperature of the vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon. With this method, a compound semiconductor crystal with a carbon concentration of 0.1×1015cm−3 to 20×1015cm−3 is prepared with high reproducibility.

Abstract: A vapor phase growth apparatus 1 for growing a group III-V nitride semiconductor (GaN) comprises a reaction ampoule 3 having a container 11 disposed therein for containing a group III element and an inlet 7 for introducing nitrogen; excitation means 15 for plasma-exciting nitrogen introduced from the inlet 7; and heating means 13 for heating a seed crystal 10 disposed within the reaction ampoule 3 and the container 11; wherein, upon growing the group III-V nitride semiconductor on the seed crystal 10, nitrogen is introduced from the inlet 7, and no gas is let out from within the reaction ampoule 3.

Abstract: A method of preparing a compound semiconductor crystal is able to dope the crystal with carbon with high reproducibility. The method includes the steps of sealing a carbon oxide gas of a predetermined partial pressure and a compound semiconductor material in a gas-impermeable airtight vessel, increasing the temperature of the vessel to melt the compound semiconductor material sealed in the vessel, and then decreasing the temperature of the vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon. With this method, a compound semiconductor crystal with a carbon concentration of 0.1×1015 cm−3 to 20×1015 cm−3 is prepared with high reproducibility.

Abstract: An apparatus and method of providing a large semiconductor crystal at a low cost are provided. The apparatus of producing a semiconductor crystal includes a reactor tube having an open end at least one end side, formed of any one material selected from the group consisting of silicon carbide, silicon nitride, aluminum nitride, and aluminum oxide, or of a composite material with any one material selected from the group consisting of silicon carbide, silicon nitride, aluminum nitride, boron nitride, aluminum oxide, magnesium oxide, mullite, and carbon as a base, and having an oxidation-proof or airtight film formed on the surface of the base, a kanthal heater arranged around the reactor tube in the atmosphere, a flange attached at the open end to seal the reactor tube, and a crucible mounted in the reactor tube to store material of a semiconductor crystal. The material stored in the crucible is heated and melted to form material melt. The material melt is solidified to grow a semiconductor crystal.

Abstract: There is provided a method of preparing a compound semiconductor crystal, allowing the compound semiconductor crystal to be doped with carbon in high reproducibility. The method includes the steps of sealing carbon oxide gas of a predetermined partial pressure and compound semiconductor material in a gas-impermeable airtight vessel, increasing the temperature of the vessel to melt the compound semiconductor material sealed in the vessel, and decreasing the temperature of vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon. With this method, a compound semiconductor crystal with a carbon concentration of 0.1×1015 cm−3 to 20×1015 cm−3 is also prepared in high reproducibility.

Abstract: An apparatus for and method of producing a large semiconductor crystal at a low cost are provided. The apparatus for producing a semiconductor crystal includes a reactor (1) having an open end at both ends thereof, that is formed of any material selected from the group consisting of silicon carbide, silicon nitride, aluminum nitride, and aluminum oxide, or of a composite material including a base material selected from the group consisting of silicon carbide, silicon nitride, aluminum nitride, boron nitride, aluminum oxide, magnesium oxide, mullite, and carbon as a base, and including an oxidation-proof or airtight film formed on the surface of the base. The apparatus further includes a resistance heater (3) arranged around the reactor (1) in the atmosphere, a flange (9) attached at the open end to seal the reactor (1), and a crucible (2) mounted in the reactor (1) to store material of a semiconductor crystal. The material stored in the crucible (2) is heated and melted to form a material melt (60).

Abstract: An apparatus comprises a Ga-disposing section in which Ga is disposed; a seed-crystal-disposing section in which a seed crystal of GaN is disposed; a synthesis vessel adapted to accommodate the Ga-disposing section, the seed-crystal-disposing section, and a gas containing nitrogen; heating means adapted to heat the Ga-disposing section and the seed-crystal-disposing section; and a control section for transmitting to the heating means a command for heating the Ga to an evaporation temperature of Ga or higher and heating the seed crystal to a temperature higher than that of the Ga, wherein the Ga evaporated by the heating means is adapted to react with the nitrogen of a nitrogen component in the gas so as to yield a GaN-forming gas, the GaN-forming gas being adapted to reach the seed-crystal-disposing section.

Abstract: A method is provided for preparing, with high reproducibility, a carbon-doped group III-V compound semiconductor crystal having favorable electrical characteristics and having impurities removed therefrom, and in which the amount of doped carbon can be adjusted easily during crystal growth. This method includes the steps of: filling a crucible with compound raw material, solid carbon, and boron oxide; sealing the filled crucible gas impermeable material; heating and melting the compound raw material under the sealed state in the airtight vessel; and solidifying the melted compound raw material to grow a carbon-doped compound semiconductor crystal.

Abstract: According to the present invention, in the growth of an oxide single crystal or a compound semiconductor single crystal such as GaAs single crystal by the CZ method or LEC method, the tendency of concave solid-liquid interface shape at the periphery of the growing crystal can be suppressed to prevent polycrystallization without localized heating of the solid-liquid interface, while controlling the diameter of the growing crystal even when using a crucible with a larger diameter, thus improving the yield of crystal on a commercial scale. In the invention, the end of a cylindrical body having an inner diameter of larger than the predetermined diameter of straight part of the growing crystal is immersed in the raw material melt or liquid encapsulant and the crystal is pulled while preventing the shape of the solid-liquid interface from becoming concave by controlling the rotation rate of at least one of a crucible holding the raw material melt, the growing crystal and cylindrical body.

Abstract: A method is provided for preparing, with high reproducibility, a carbon-doped group III-V compound semiconductor crystal having favorable electrical characteristics and having impurities removed therefrom, and in which the amount of doped carbon can be adjusted easily during crystal growth. This method includes the steps of: filling a crucible with compound raw material, solid carbon, and boron oxide; sealing the filled crucible within an airtight vessel formed of a gas impermeable material; heating and melting the compound raw material under the sealed state in the airtight vessel; and solidifying the melted compound raw material to grow a carbon-doped compound semiconductor crystal.

Abstract: A method of preparing a compound semiconductor crystal is able to dope the crystal with carbon with high reproducibility. The method includes the steps of sealing a carbon oxide gas of a predetermined partial pressure and a compound semiconductor material in a gas-impermeable airtight vessel, increasing the temperature of the vessel to melt the compound semiconductor material sealed in the vessel, and then decreasing the temperature of the vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon. With this method, a compound semiconductor crystal with a carbon concentration of 0.1×1015cm?3 to 20×1015cm?3 is prepared with high reproducibility.

Abstract: A method is provided for preparing, with high reproducibility, a carbon-doped group III-V compound semiconductor crystal having favorable electrical characteristics and having impurities removed therefrom, and in which the amount of doped carbon can be adjusted easily during crystal growth. This method includes the steps of: filling a crucible with compound raw material, solid carbon, and boron oxide; sealing the filled crucible gas impermeable material; heating and melting the compound raw material under the sealed state in the airtight vessel; and solidifying the melted compound raw material to grow a carbon-doped compound semiconductor crystal.

Abstract: A method of preparing a compound semiconductor crystal is able to dope the crystal with carbon with high reproducibility. The method includes the steps of sealing a carbon oxide gas of a predetermined partial pressure and a compound semiconductor material in a gas-impermeable airtight vessel, increasing the temperature of the vessel to melt the compound semiconductor material sealed in the vessel, and then decreasing the temperature of the vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon. With this method, a compound semiconductor crystal with a carbon concentration of 0.1×1015cm?3 to 20×1015cm?3 is prepared with high reproducibility.