Shin-etsu Handotai Co., Ltd.

Hiroyuki Kamada

Ryoji Hoshi

Kiyotaka Takano

Kosei Sugawara

Tomohiko Ohta

Suguru Matsumoto

Wataru Yajima

Takahide Onai

A single-crystal pulling apparatus includes: a pulling furnace having a heater and crucible; and a magnetic field generation device having superconducting coils, the device having four of the superconducting coils, two of the superconducting coils are in each of two regions divided by a cross section that includes an X axis being a direction of magnetic force lines at the central axis in the horizontal plane including all the coil axes of the four superconducting coils, and includes the pulling furnace central axis having line symmetry about the cross section, the four superconducting coils are all arranged so that the coil axes have an angle of more than −30° and less than 30° relative to a Y axis, the direction of the magnetic force lines thereof have line symmetry about the cross section, and in each of the regions, the two superconducting coils generate magnetic force lines in opposite directions.

Single-crystal pulling apparatus and single-crystal pulling method

A single-crystal pulling apparatus including: a pulling furnace having a central axis; and a magnetic field generation device arranged around the pulling furnace and having superconducting coils, the apparatus applying a horizontal magnetic field to the molten semiconductor raw material, two coil axes in the two pairs of the superconducting coils are included in a single horizontal plane, and when a direction of lines of magnetic force at the central axis of the pulling furnace in the horizontal plane is determined as an X axis, a center angle α having the X axis between the two coil axes is 100 degrees or more and 120 degrees or less. This makes it possible to reduce the height of the coils, to raise the magnetic field center close to the melt surface of the semiconductor raw material, and to obtain a single crystal having a lower oxygen concentration than conventional single crystals.

Single-crystal pulling apparatus with saddle-shaped superconducting coils and single-crystal pulling method

A method controls a resistivity of a grown silicon single crystal by using a dopant when the silicon single crystal is grown by CZ method, including the steps of initially doping with a primary dopant such that the silicon single crystal has a predetermined conductive type and additionally doping with a secondary dopant having a conductive type opposite to that of the primary dopant continuously or intermittently, according to a solidification rate expressed by (crystalized weight)/(initial weight of silicon raw material) while growing the silicon single crystal, wherein in the additional doping step, the additional doping with the secondary dopant is carried out when the solidification rate is a predetermined value &#x3b1; or more, while the crystal is not doped with the secondary dopant until the solidification rate reaches the predetermined value &#x3b1;.

Method for controlling resistivity and N-type silicon single crystal

A method for a heat treatment of a silicon single crystal wafer in an oxidizing ambient, including: performing the heat treatment based on a condition determined by a tripartite correlation between a heat treatment temperature during the heat treatment, an oxygen concentration in the silicon single crystal wafer before the heat treatment, and a growth condition of a silicon single crystal from which the silicon single crystal wafer is cut out. This provides a method for a heat treatment of a silicon single crystal wafer which can annihilate void defects or micro oxide precipitate nuclei in a silicon single crystal wafer with low cost, efficiently, and securely by a heat treatment in an oxidizing ambient.

Method for heat treatment of silicon single crystal wafer

The present invention is a method for a heat treatment of a silicon single crystal wafer in an oxidizing ambient, including: performing the heat treatment based on a condition determined by a tripartite correlation between a heat treatment temperature during the heat treatment, an oxygen concentration in the silicon single crystal wafer before the heat treatment, and a void size in the silicon single crystal wafer before the heat treatment. This provides a method for a heat treatment of a silicon single crystal wafer which can annihilate void defects or micro oxide precipitate nuclei in a silicon single crystal wafer with low cost, efficiently, and securely by a heat treatment in an oxidizing ambient.

A method for evaluating concentration of defect in silicon single crystal substrate, defect being formed by particle beam irradiation in silicon single crystal substrate, including the steps of: measuring a resistivity of silicon single crystal substrate, followed by irradiating silicon single crystal substrate with particle beam, re-measuring resistivity of silicon single crystal substrate after irradiation; determining each carrier concentration in silicon single crystal substrate before and after irradiation on basis of measured results of resistivity before and after particle beam irradiation to calculate rate of change of carrier concentration; and evaluating concentration of VV defect on basis of rate of change of carrier concentration, VV defect being made of a silicon atom vacancy and being formed by particle beam irradiation in silicon single crystal substrate. The method can simply evaluate concentration of VV defect formed in silicon single crystal substrate by particle beam irradiation.

Method for evaluating concentration of defect in silicon single crystal substrate

The present invention provides a method for manufacturing a silicon single crystal wafer, wherein, under a growth condition that V/G&#x2267;1.05&#xd7;(V/G)crt is achieved where V is a growth rate in growth of the silicon single crystal ingot, G is a temperature gradient near a crystal growth interface, and (V/G)crt is a value of V/G when a dominant point defect changes from a vacancy to interstitial Si, a silicon single crystal ingot having oxygen concentration of 7&#xd7;10atoms/cm(ASTM'79) or less is grown, and a silicon single crystal wafer which includes a region where the vacancy is dominant and in which FPDs are not detected by preferential etching is manufactured from the grown silicon single crystal ingot. As a result, there is provided the method that enables manufacturing a low-oxygen concentration silicon single crystal wafer that can be preferably used for a power device with good productivity at a low cost.

Method for manufacturing a defect-controlled low-oxygen concentration silicon single crystal wafer

The present invention provides a method for evaluating silicon single crystal wherein an amount &#x394;[C] of carriers generated due to oxygen donors produced when a heat treatment is performed to the silicon single crystal is calculated and evaluated, the amount &#x394;[C] being calculated from oxygen concentration [Oi] in the silicon single crystal, a temperature T of the heat treatment, a time t of the heat treatment, and an oxygen diffusion coefficient D(T) at the temperature T by using the following relational expression:&#x394;[C]=&#x3b1;[Oi]&#xd7;exp(&#x2212;&#x3b2;&#xb7;D(T)&#xb7;[Oi]&#xb7;t)

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Nishigo-mura, Japan

Hiroyuki Kamada