Nitrogen-doped CZ silicon crystal ingots and wafers sliced therefrom are disclosed that provide for post epitaxial thermally treated wafers having oxygen precipitate density and size that are substantially uniformly distributed radially and exhibit the lack of a significant edge effect. Methods for producing such CZ silicon crystal ingots are also provided by controlling the pull rate from molten silicon, the temperature gradient and the nitrogen concentration. Methods for simulating the radial bulk micro defect size distribution, radial bulk micro defect density distribution and oxygen precipitation density distribution of post epitaxial thermally treated wafers sliced from nitrogen-doped CZ silicon crystals are also provided.

A convection pattern control method includes: heating a silicon melt in a quartz crucible using a heating portion; and applying a horizontal magnetic field to the silicon melt in the quartz crucible being rotated. In the heating of the silicon, the silicon melt is heated with the heating portion whose heating capacity differs on both sides across an imaginary line passing through a center axis of the quartz crucible and being in parallel to a central magnetic field line of the horizontal magnetic field when the quartz crucible is viewed from vertically above. In the applying of the horizontal magnetic field, the horizontal magnetic field of 0.2 tesla or more is applied to fix a direction of a convection flow in a single direction in a plane orthogonal to an application direction of the horizontal magnetic field in the silicon melt.

An ingot growing apparatus is composed of a neck portion, a shoulder portion, a body portion, and a tail portion. The ingot growing apparatus comprises a memory configured to store an artificial neural network and a processor.

The processor learns the artificial neural network to obtain a primary shoulder shape model corresponding to training data, updates the obtained primary shoulder shape model based on shoulder information obtained during the growth of a shoulder portion of a first ingot to obtain a secondary shoulder shape model, sets a target tail temperature for growth a tail portion of the first ingot based on the secondary shoulder shape model, and controls the growth of the tail portion of the first ingot according to the set target tail temperature.

Nitrogen-doped CZ silicon crystal ingots and wafers sliced therefrom are disclosed that provide for post epitaxial thermally treated wafers having oxygen precipitate density and size that are substantially uniformly distributed radially and exhibit the lack of a significant edge effect. Methods for producing such CZ silicon crystal ingots are also provided by controlling the pull rate from molten silicon, the temperature gradient and the nitrogen concentration. Methods for simulating the radial bulk micro defect size distribution, radial bulk micro defect density distribution and oxygen precipitation density distribution of post epitaxial thermally treated wafers sliced from nitrogen-doped CZ silicon crystals are also provided.

Provided is an indium phosphide substrate, a semiconductor epitaxial wafer, a method for producing an indium phosphide single-crystal ingot and a method for producing indium phosphide substrate capable of suppressing concave defects. An indium phosphide substrate has a diameter of 100 mm or less, and at least one of surfaces has zero concave defects detected in the topography channel, by irradiating a laser beam of 405 nm wavelength with S-polarized light on the surface.

Epitaxially coated semiconductor wafers of monocrystalline silicon comprise a p.sup.+-doped substrate wafer and a p-doped epitaxial layer of monocrystalline silicon which covers an upper side face of the substrate wafer;

an oxygen concentration of the substrate wafer of not less than 5.3×10.sup.17 atoms/cm.sup.3 and not more than 6.0×10.sup.17 atoms/cm.sup.3;

a resistivity of the substrate wafer of not less than 5 mΩcm and not more than 10 mΩcm; and

the potential of the substrate wafer to form BMDs as a result of a heat treatment of the epitaxially coated semiconductor wafer, where a high density of BMDs has a maximum close to the surface of the substrate wafer.

Epitaxially coated semiconductor wafers of monocrystalline silicon comprise a p.sup.+-doped substrate wafer and a p-doped epitaxial layer of monocrystalline silicon which covers an upper side face of the substrate wafer; an oxygen concentration of the substrate wafer of not less than 5.3×10.sup.17 atoms/cm.sup.3 and not more than 6.0×10.sup.17 atoms/cm.sup.3; a resistivity of the substrate wafer of not less than 5 mΩcm and not more than 10 mΩcm; and
the potential of the substrate wafer to form BMDs as a result of a heat treatment of the epitaxially coated semiconductor wafer, where a high density of BMDs has a maximum close to the surface of the substrate wafer.

Single crystal silicon with <100> orientation is doped with n-type dopant and comprises a starting cone, a cylindrical portion and an end cone, a crystal angle being not less than 20° and not greater than 30° in a middle portion of the starting cone, the length of which is not less than 50% of a length of the starting cone, and edge facets extending from a periphery of the single crystal into the single crystal, the edge facets in the starting cone and in the cylindrical portion of the single crystal in each case having a length which is not more than 700 μm.

An n-type silicon single crystal production method of pulling up a silicon single crystal from a silicon melt containing red phosphorus as a principal dopant and growing the silicon single crystal by the Czochralski process, the method including: controlling electrical resistivity at a start position of a straight body portion of the silicon single crystal to 0.80 mΩcm or more and 1.05 mΩcm or less; and sequentially lowering the electrical resistivity of the silicon single crystal as the silicon single crystal is up and grown, thereby adjusting electrical resistivity of a part of the silicon single crystal to 0.5 mΩm or more and less than 0.6 mΩcm.

Nitrogen-doped CZ silicon crystal ingots and wafers sliced therefrom are disclosed that provide for post epitaxial thermally treated wafers having oxygen precipitate density and size that are substantially uniformly distributed radially and exhibit the lack of a significant edge effect. Methods for producing such CZ silicon crystal ingots are also provided by controlling the pull rate from molten silicon, the temperature gradient and the nitrogen concentration. Methods for simulating the radial bulk micro defect size distribution, radial bulk micro defect density distribution and oxygen precipitation density distribution of post epitaxial thermally treated wafers sliced from nitrogen-doped CZ silicon crystals are also provided.