Abstract: A crystal piece of monocrystalline silicon suitable for the production of semiconductor wafers has a length of not less than 8 cm and not more than 50 cm and a diameter of not less than 280 mm and not greater than 320 mm, wherein the fraction of the semiconductor wafers produced therefrom that are free from pinholes having a size of not more than 30 ?m is greater than 98%.

Abstract: A fused quartz crucible for pulling a single crystal of silicon by the Czochralski technique, has an inner side with an inner layer of fused quartz that forms a surface, the inner layer being provided with a crystallization promoter which on heating of the fused quartz crucible during use, in crystal pulling, causes crystallization of fused quartz to form b-cristobalite, wherein the concentration C of synthetically obtained SiO2 at a distance d from the surface is greater than the concentration of synthetically obtained SiO2 at a distance d2 from the surface, where d2 is greater than d. Multiple crystals can be grown while maintaining high crystal quality.