A method for producing a silicon single crystal, wherein a silicon nitride powder is introduced into a raw material before start of melting and the silicon single crystal doped with nitrogen is pulled by Czochralski method, wherein nitrogen doping is performed while an upper limit amount of usable silicon nitride powder is limited based on an amount of carbon impurities contained in the silicon nitride powder so that a carbon concentration in the silicon single crystal is equal to or less than allowable value. This makes it possible to achieve the required nitrogen doping amount at low cost while achieving the low carbon-concentration specification.

A method for producing a silicon single crystal, wherein a silicon nitride powder is introduced into a raw material before start of melting and the silicon single crystal doped with nitrogen is pulled by Czochralski method, wherein nitrogen doping is performed while an upper limit amount of usable silicon nitride powder is limited based on an amount of carbon impurities contained in the silicon nitride powder so that a carbon concentration in the silicon single crystal is equal to or less than allowable value. This makes it possible to achieve the required nitrogen doping amount at low cost while achieving the low carbon-concentration specification.

Silicon particles with a reduced and/or delayed propensity to generate hydrogen gas by reaction with water in aqueous inks for preparing lithium ion battery anodes are prepared by milling silicon, preferably in an oxidative atmosphere, followed by heat treating at an elevated temperature in vacuum or an inert atmosphere.

A semiconductor wafer comprises a substrate wafer of monocrystalline silicon and a dopant-containing epitaxial layer of monocrystalline silicon atop the substrate wafer, wherein a non-uniformity of the thickness of the epitaxial layer is not more than 0.5% and a non-uniformity of the specific electrical resistance of the epitaxial layer is not more than 2%.

A semiconductor wafer comprises a substrate wafer of monocrystalline silicon and a dopant-containing epitaxial layer of monocrystalline silicon atop the substrate wafer, wherein a non-uniformity of the thickness of the epitaxial layer is not more than 0.5% and a non-uniformity of the specific electrical resistance of the epitaxial layer is not more than 2%.

A magnet coil for magnetic Czochralski single crystal growth includes: a first coil, a second coil, and an auxiliary coil arranged between the first coil and the second coil. A distance between the first coil and a first edge of the auxiliary coil close to the first coil is equal to a distance between the second coil and a second edge of the auxiliary coil close to the second coil. The auxiliary coil, the first coil and the second coil have a common central axis. When being energized, a direction of a current in the first coil is opposite to a direction of a current in the second coil, and a magnetic field generated by a current in the auxiliary coil is used for enhancing a cusp magnetic field between the first coil and the second coil.

A magnet coil for magnetic Czochralski single crystal growth includes: a first coil, a second coil, and an auxiliary coil arranged between the first coil and the second coil. A distance between the first coil and a first edge of the auxiliary coil close to the first coil is equal to a distance between the second coil and a second edge of the auxiliary coil close to the second coil. The auxiliary coil, the first coil and the second coil have a common central axis. When being energized, a direction of a current in the first coil is opposite to a direction of a current in the second coil, and a magnetic field generated by a current in the auxiliary coil is used for enhancing a cusp magnetic field between the first coil and the second coil.

A method of producing an epitaxial silicon wafer, including: loading a wafer into a chamber; performing epitaxial growth; unloading the epitaxial silicon wafer from the chamber; and then cleaning the inside of the chamber using hydrochloric gas. After the cleaning is performed, whether components provided in the chamber are to be replaced or not is determined based on the cumulative amount of the hydrochloric gas supplied. The components have a base material that includes graphite and is coated with a silicon carbide film.

A method of producing an epitaxial silicon wafer, including: loading a wafer into a chamber; performing epitaxial growth; unloading the epitaxial silicon wafer from the chamber; and then cleaning the inside of the chamber using hydrochloric gas. After the cleaning is performed, whether components provided in the chamber are to be replaced or not is determined based on the cumulative amount of the hydrochloric gas supplied. The components have a base material that includes graphite and is coated with a silicon carbide film.

In a side view, when an angle θ1 formed between the light axis of light incident on a surface of a silicon wafer and the surface (or an imaginary plane corresponding to the surface) is 67° to 78° and an angle formed between the surface of the silicon wafer (or an imaginary plane corresponding to the surface) and the detection optical axis of a photodetector is θ2, θ1−θ2 is −6° to −1° or 1° to 6°.