The present invention relates to a method of manufacturing polycrystalline silicon ingot using a crucible in which an oxygen exhaust passage is formed by single crystal or polycrystalline rods, the method including the steps of: manufacturing the single crystal or polycrystalline silicon rods each having the shape of a quadrilateral pillar; putting the single crystal or polycrystalline quadrilateral pillar-shaped silicon rods into the crucible in such a manner as to be arranged close to one another along the inner peripheral surface of the crucible to thus form a space portion inside the single crystal or polycrystalline silicon rods, into which silicon chunks are put, and the oxygen exhaust passages between the inner peripheral surface of the crucible and the respective surfaces of the single crystal or polycrystalline silicon rods oriented toward the inner peripheral surface of the crucible; putting the silicon chunks into the space portion of the crucible; and melting and crystallizing the silicon chunks.

An N-type polysilicon crystal, a manufacturing method thereof, and an N-type polysilicon wafer are provided. The N-type polysilicon crystal has a slope of resistivity and a slope of defect area percentage. When the horizontal axis is referred to solidified fraction and the vertical axis is referred to resistivity presented by a unit of Ohm.Math.cm (.Math.cm), the slope of resistivity is 0 to 1.8 at the solidified fraction of 0.25 to 0.8. When the horizontal axis is referred to solidified fraction and the vertical axis is referred to defect area percentage (%), the slope of defect area percentage is less than 2.5 at the solidified fraction of 0.4 to 0.8.

A cast work piece includes a cast metal component section and a sprue section connected to the cast metal component section. The cast metal component section and a portion of the sprue section have a first grain orientation and another portion of the sprue section has a second grain orientation such that there is a microstructural discontinuity where the first grain orientation meets the second grain orientation in the sprue section.

A cast work piece includes a cast metal component section and a sprue section connected to the cast metal component section. The cast metal component section and a portion of the sprue section have a first grain orientation and another portion of the sprue section has a second grain orientation such that there is a microstructural discontinuity where the first grain orientation meets the second grain orientation in the sprue section.

A polycrystalline silicon column is provided. The polycrystalline silicon column includes a plurality of silicon grains grown along a crystal-growing direction. In the crystal-growing direction, the average grain size of the silicon grains and the resistivity of the polycrystalline silicon column have opposite variation in their trends, the average grain size of the silicon grains and the oxygen content of the polycrystalline silicon column have opposite variation in their trends, and the average grain size of the silicon grains and the defect area ratio of the polycrystalline silicon column have the same variation in their trends. The overall average defect area ratio of the polycrystalline silicon column is less than or equal to 2.5%.

A polycrystalline silicon column is provided. The polycrystalline silicon column includes a plurality of silicon grains grown along a crystal-growing direction. In the crystal-growing direction, the average grain size of the silicon grains and the resistivity of the polycrystalline silicon column have opposite variation in their trends, the average grain size of the silicon grains and the oxygen content of the polycrystalline silicon column have opposite variation in their trends, and the average grain size of the silicon grains and the defect area ratio of the polycrystalline silicon column have the same variation in their trends. The overall average defect area ratio of the polycrystalline silicon column is less than or equal to 2.5%.

Disclosed is a method for preparing polycrystalline silicon ingot. The preparation method comprises: randomly laying seed crystals with unlimited crystal orientation at the bottom of crucible to form a layer of seed crystals and obtaining disordered crystalline orientations; providing molten silicon above the layer of seed crystals, controlling the temperature at the bottom of the crucible, making the layer of seed crystals not completely melted; controlling the temperature inside the crucible, making the molten silicon growing above the seed crystals, the molten silicon inheriting the structure of the seed crystals, then obtaining polycrystalline silicon ingot. By adopting the preparation method, a desirable initial nucleus can be obtained for a polycrystalline silicon ingot, so as to reduce dislocation multiplication during the growth of the polycrystalline silicon ingot.

Disclosed is a method for preparing polycrystalline silicon ingot. The preparation method comprises: randomly laying seed crystals with unlimited crystal orientation at the bottom of crucible to form a layer of seed crystals and obtaining disordered crystalline orientations; providing molten silicon above the layer of seed crystals, controlling the temperature at the bottom of the crucible, making the layer of seed crystals not completely melted; controlling the temperature inside the crucible, making the molten silicon growing above the seed crystals, the molten silicon inheriting the structure of the seed crystals, then obtaining polycrystalline silicon ingot. By adopting the preparation method, a desirable initial nucleus can be obtained for a polycrystalline silicon ingot, so as to reduce dislocation multiplication during the growth of the polycrystalline silicon ingot.

An N-type polysilicon crystal, a manufacturing method thereof, and an N-type polysilicon wafer are provided. The N-type polysilicon crystal has a slope of resistivity and a slope of defect area percentage. When the horizontal axis is referred to solidified fraction and the vertical axis is referred to resistivity presented by a unit of Ohm.Math.cm (.Math.cm), the slope of resistivity is 0 to 1.8 at the solidified fraction of 0.25 to 0.8. When the horizontal axis is referred to solidified fraction and the vertical axis is referred to defect area percentage (%), the slope of defect area percentage is less than 2.5 at the solidified fraction of 0.4 to 0.8.

Molded articles and methods for forming molded articles are provided. For example, a molded article comprises a first region formed by a first casting material and a second region formed by mixing a molten or liquid portion of the first casting material and a second casting material. The first casting material is a molten, liquid, or fluid metal alloy, and the second casting material is a molten or fluid metal alloy. The first casting material has a different chemical composition than the second casting material. The first region and the second region are cast as one integral casting using directional solidification, and the first region and the second region have different microstructure patterns. The molded article has a lower concentration of impurities than were present in the first and second casting materials, and an interface between the first region and the second region is devoid of an oxidation layer.