Semiconductor wafers useful for NAND circuitry and having a front side, a rear side, a middle and a periphery, have an Nv region which extends from the middle to the periphery; a denuded zone which extends from the front side to a depth of not less than 20 m into the interior of the semiconductor wafer, where the density of vacancies in the denuded zone, determined by means of platinum diffusion and DLTS is not more than 110.sup.13 vacancies/cm.sup.3; a concentration of oxygen of not less than 4.510.sup.17 atoms/cm.sup.3 and not more than 5.510.sup.17 atoms/cm.sup.3; a region in the interior of the semiconductor wafer which adjoins the denuded zone and has nuclei which can be developed by means of a heat treatment into BMDs having a peak density of not less than 6.010.sup.9/cm.sup.3, where the heat treatment comprises heating the semiconductor wafer to a temperature of 800 C. over a period of four hours and to a temperature of 1000 C. over a period of 16 hours. The wafers are produced by a unique RTA treatment of Nv wafers.

Provided is a heat shielding member, a single crystal pulling apparatus, and a method of producing a single crystal silicon ingot, which can expand the margin of the crystal pulling rate with which a defect-free single crystal silicon can be obtained. A heat shielding member is provided in a single crystal pulling apparatus, the heat shielding member including a cylindrical tubular portion surrounding an outer circumferential surface of the single crystal silicon ingot; and a ring-shaped projecting portion under the tubular portion. The projecting portion has an upper wall, a bottom wall, and two vertical walls, a heat insulating material with a ring shape is provided in the space surrounded by those walls; and a gap between the vertical wall adjacent to the single crystal silicon ingot and the heat insulating material.

A mono-crystalline silicon growth method includes: providing a furnace, a supporting base and a crucible which do not rotate relative to the furnace, and a heating module disposed at an outer periphery of the supporting base. After solidifying a liquid surface of a silicon melt in the crucible to form a crystal, the heating power of the heating module is successively reduced to appropriately adjust the temperature around the crucible to effectively control a temperature gradient of a thermal field around the crucible, so as to form a mono-crystalline silicon ingot by solidifying the silicon melt.

A RAMO.sub.4 substrate that does not easily crack during or after the formation of group III nitride crystal includes a single crystal represented by general formula RAMO.sub.4 (wherein R represents one or more trivalent elements selected from the group consisting of Sc, In, Y, and lanthanoid elements, A represents one or more trivalent elements selected from the group consisting of Fe(III), Ga, and Al, and M represents one or more divalent elements selected from the group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). The RAMO.sub.4 substrate has a crystal plane with a curvature radius r of 52 m or more, and a square value of correlation coefficient of 0.81 or more. The curvature radius r is calculated as an absolute value from X-ray peak position i and measurement position Xi after the measurements of X-ray peak positions i at a plurality of positions Xi lying on a straight line passing through the center of the RAMO.sub.4 substrate. The correlation coefficient is a measure of correlation between and measurement position Xi.

A semiconductor wafer made of single-crystal silicon has an oxygen concentration (new ASTM) of not less than 4.910.sup.17 atoms/cm.sup.3 and not more than 6.510.sup.7 atoms/cm.sup.3 and a nitrogen concentration (new ASTM) of not less than 810.sup.12 atoms/cm.sup.3 and not more than 510.sup.13 atoms/cm.sup.3, wherein a frontside of the semiconductor wafer is covered with an epitaxial layer made of silicon, wherein the semiconductor wafer comprises BMDs of octahedral shape whose mean size is 13 to 35 nm, and whose mean density is not less than 310.sup.8 cm.sup.3 and not more than 410.sup.9 cm.sup.3, as determined by IR tomography.

This invention provides method, device, system, and computer storage medium for crystal growth control of a shouldering process. The method comprises: presetting setting values of a crystal diameter variation, and a shouldering length variation at different stages of a shouldering process and a crystal growth process parameter at different stages of the shouldering process; obtaining crystal diameters at different stages of the shouldering process and calculating a measured crystal diameter variation; obtaining shouldering lengths at different stages of the shouldering process and calculating a measured shouldering length variation; comparing a ratio of the measured crystal diameter variation and the measured shouldering length variation with a ratio of the setting values of the crystal diameter variation and the shouldering length variation to obtain a difference as an input variable of PID algorithm; calculating an adjustment value of a crystal growth process parameter by PID algorithm as an output variable of PID algorithm; adding the adjustment value of the crystal growth process parameter and the setting value of the crystal growth process parameter to obtain a process parameter of an actual crystal growth process. The method, device and system and computer storage medium control the crystal diameter variation during the shouldering process by PID algorithm to overcome an influence of small changes in the thermal field to the shouldering process, ensure the changing value of the crystal diameter is consistent, and improve the repeatability of the shouldering process and the stability of the process.

An oxychloride infrared nonlinear optical crystal and the preparation method and use thereof, the optical crystal has a general chemical formula of Pb.sub.2+xOCl.sub.2+2x, therein 0<x<0.139 or 0.141<x<0.159 or 0.161<x0.6. The crystal is non-centrosymmetric, belongs to orthonormal system with space group of Fmm2, cell parameter is a=35.4963(14)0.05 , b=5.8320(2)0.05 , c=16.0912(6)0.05 . The crystal is prepared by high temperature melt method or flux method. The crystal has a strong second harmonic generation efficiency of 4 times that of KDP (KH.sub.2PO.sub.4) tested by Kurtz method, it is phase machable, transparent in the range of 0.34-7 m. The laser damage threshold is 10 times that of the current commercial infrared nonlinear optical crystal AgGaS.sub.2. No crystalline water exists in lead oxychloride, and it is stable in the air and has good thermal stability.

A method of producing a monocrystalline silicon uses a monocrystal pull-up apparatus including a crucible, a crucible driver, a pull-up portion, a heat shield having a circular hollow cylindrical lower end portion, and a chamber. The heat shield satisfies a formula (1) below in growing the monocrystalline silicon,

R1.27C(1) where C represents a radius (mm) of a straight body of the monocrystalline silicon, and R represents an inner radius (mm) at the lower end portion of the heat shield.

An embodiment provides a method for manufacturing a silicon single crystal ingot by using a silicon single crystal growing apparatus comprising: a chamber; a crucible arranged inside the chamber and accommodating a molten silicon solution; a heater arranged outside the crucible so as to heat the crucible; a heat shielding part arranged inside the chamber; and a pulling part for pulling a single crystal growing from the molten silicon solution, wherein the method can comprise a step of respectively growing a neck part, a shoulder part and a body part.

There are provided a solid electrolyte material having high density and ion conductivity, and an all solid lithium ion secondary battery using the solid electrolyte material. The solid electrolyte material has a garnet-related structure which has a chemical composition represented by Li.sub.7-x-yLa.sub.3Zr.sub.2-x-yTa.sub.xNb.sub.yO.sub.12 (0x0.8, 0.2y1, and 0.2x+y1) and relative density of 99% or greater, and belongs to a cubic system. The solid electrolyte material has lithium ion conductivity which is equal to or greater than 1.010.sup.3 S/cm. The solid electrolyte material has a lattice constant a which satisfies 1.28 nma1.30 nm, and has a lithium ion which occupies only two or more 96h sites in a crystal structure. The all solid lithium ion secondary battery includes a positive electrode, a negative electrode, and a solid electrolyte. The solid electrolyte includes the solid electrolyte material.