Abstract: A silicon wafer produced from a silicon single crystal ingot grown by Czochralski process is subjected to rapid heating/cooling thermal process at a maximum temperature (T1) of 1300° C. or more, but less than 1380° C. in an oxidizing gas atmosphere having an oxygen partial pressure of 20% or more, but less than 100%. The silicon wafer according to the invention has, in a defect-free region (DZ layer) including at least a device active region of the silicon wafer, a high oxygen concentration region having a concentration of oxygen solid solution of 0.7×1018 atoms/cm3 or more and at the same time, the defect-free region contains interstitial silicon in supersaturated state.

Abstract: A silicon wafer produced from a silicon single crystal ingot grown by Czochralski process is subjected to rapid heating/cooling thermal process at a maximum temperature (T1) of 1300° C. or more, but less than 1380° C. in an oxidizing gas atmosphere having an oxygen partial pressure of 20% or more, but less than 100%. The silicon wafer according to the invention has, in a defect-free region (DZ layer) including at least a device active region of the silicon wafer, a high oxygen concentration region having a concentration of oxygen solid solution of 0.7×1018 atoms/cm3 or more and at the same time, the defect-free region contains interstitial silicon in supersaturated state.

Abstract: An integrated submerged entry nozzle for thin slab continuous casting has a plate member 12 corresponding to the lower plate of a slide gate and a nozzle member 11 having a flat molten steel passage section in the part to be submerged into molten steel of at least the tip, the both 11. 12 being integrated together by the use of an organic adhesive. The plate member 12 and the nozzle member 11 are separately formed followed by baking or firing, the both 11, 12 are adhered together by the use of an organic adhesive, the adhesive is dried, the outside is covered with a shell, and refractory mortar is filled in the space. Thereafter, a refractory ring 28 is adhered in such a manner as to cover the inside of the adhesive joint part followed by drying.

Abstract: In a flat casting nozzle 10 having a taper 13, the position of the terminal end 14 of the taper 13 formed on the long edge side and the position of the terminal end 17 of a taper 16 formed on the short edge side are mutually shifted.

Abstract: Provided is a refractory for casting which contains clinker having a mineral crystal phase consisting essentially of mullite and baddeleyite. The refractory for casting has excellent in a thermal-shock resistance, corrosion resistance and strength. The refractory for casting is manufactured from a raw material containing a refractory composition and an organic binder, wherein the refractory composition comprises(a) 3 to 60 wt % of clinker having a mineral crystal phase consisting essentially of mullite and baddeleyite, and containing 5 to 22 wt % of alumina (Al.sub.2 O.sub.3), 38 to 68 wt % of zirconia (ZrO.sub.2) and 27 to 40 wt % of silica;(b) 5 to 40 wt % of at least one carbon-based material selected from the group consisting of graphite and carbon; and(c) at least one refractory element as a balance, selected from the group consisting of alumina, fused silica, zirconia, silicon carbide, mullite and a metal silicon.