Abstract: Quick and inexpensive determination of an aggregate of point defects in a grown silicon semiconductor single crystal bar is accomplished by a method which comprises cutting a wafer from a freshly grown silicon single crystal bar, etching the surface of this wafer with the mixture of hydrofluoric acid and nitric acid thereby relieving the wafer of strain, treating the wafer with the mixture of K.sub.2 Cr.sub.2 O.sub.7, hydrofluoric acid, and water thereby giving rise to pits 2 and ripple patterns 1 therein, determining the density of the pits 2 and that of the ripple patterns 1, and rating the aggregate of point defects by virtue of the correlation between the densities of the pits 1 and the ripple patterns 1 and the aggregate of point defects.

Abstract: A single crystal pulling apparatus based on Czochralski technique having a conduit for continuously supplying granular polycrystal material to the crucible and a vertical purge tube suspended centrally into the heating chamber, wherein the purge tube is vertically shiftable; a heat shield ring is connected to the lower end of the purge tube, and a cylindrical quartz partition ring made of a quartz glass containing no bubbles is held vertically by the heat shield ring in a manner such that the lower end of the quartz partition ring comes substantially lower than the lower end of the purge tube so that, by being dipped in the polycrystal melt, the partition ring isolates the interior surface of the melt from the exterior surface of the melt, over which latter the granular polycrystal material is poured.

Abstract: A single crystal pulling apparatus of Czochralski technique type including (i) a cylindrical partition adapted to divide the surface portion of the melt into an inner part and an outer part, the former being where the single crystal is grown and the latter being where granular polycrystal material is supplied, (ii) a flat ring having heat reflecting and insulating property held horizontally above the melt, and (iii) a vertically shiftable purge tube suspended centrally into the heating chamber adapted to enter into the inner hole of the flat ring.

Abstract: A semiconductor single crystal rod having a controlled oxygen concentration distribution in the direction of length is produced by method of pulling up a semiconductor melt held in a quartz glass crucible under application of a magnetic field, which method is characterized by fixing the speed of revolution of the quartz glass crucible and varying the intensity of the magnetic field applied to the melt according to the length of pull-up of the single crystal rod.

Abstract: A process for producing a silicon single crystal is disclosed which comprises the steps of providing a silicon melt in a crucible, feeding grains of silicon polycrystal to the silicon melt and pulling up a silicon single crystal from the silicon melt. The concentration of residual hydrogen in the grains of silicon polycrystal is more than 10 ppmwt and less than 100 ppmwt. The process prevents the silicon single crystal from being polycrystalline.

Abstract: A semiconductor single crystal rod having a controlled oxygen concentration distribution in the direction of length is produced by method of pulling up a semiconductor melt held in a quartz glass crucible under application of a magnetic field, which method is characterized by fixing the rotational speed of said quartz crucible at a level exceeding 5 rpm and varying the intensity of said magnetic field applied to said molten semiconductor according to the length of pull of said single crystal rod.

Abstract: A semiconductor device of the MOS construction such that a gate oxide film of the device has a gate area in the range of from 5 to 15 mm.sup.2 and a thickness in the range of from 15 to 40 nm and the oxide film dielectric breakdown voltage is not less than 8 MV/cm when a gate current caused to flow in response to application of a direct-current voltage between a phosphorus-doped polysilicon electrode formed on the oxide film and a silicon single crystal substrate increases past 1 .mu.A/mm.sup.2 as current density is obtained by using a silicon wafer substrate having an oxygen concentration of not more than 1.times.10.sup.18 atoms/cm.sup.3.

Abstract: A method of producing a Czochralski-grown silicon single crystal stably and efficiently with high production yield comprises the steps of setting pulling conditions such that at least a portion of a growing silicon single crystal having a temperature in excess of 1150.degree. C. is spaced upwardly from a surface of silicon melt by a distance greater than 280 mm; and pulling the growing silicon single crystal upward while maintaining the pulling conditions. The silicon single crystal produced by this method has an excellent oxide film dielectric breakdown strength. An apparatus for carrying out the method is also disclosed.

Abstract: In a method for heat process of silicon, a single crystal silicon produced by the Czochralski process is thermally processed at a low temperature ranging from 400.degree. C. to 550.degree. C. Outside this temperature range, the oxygen precipitate is not adequate. The result is that a predetermined oxygen precipitate can be obtained uniformly in the crystal growth direction without any reduction especially at the crystal bottom part. The resulting silicon is particularly suitable for manufacture of LSI.

Abstract: An improved apparatus for growing a single crystal of semiconductor silicon by the Czochralski method which apparatus has a heat-resistant and heat-insulating covering board in direct contact with the upper ends of heat-insulating members surrounding a quartz glass silicon melting crucible and having a circular center opening, and a heat-resistant and heat-insulating tube having an outer diameter approximately equal to the diameter of the center opening in the covering board gas-tightly joined to an upwardly extending argon gas supplying conduit and extending downwardly from the joint of the top wall of a metal housing and the upwardly extending conduit and extending through the center opening in the covering board in such a manner that the single crystal during growing is coaxially surrounded thereby, the lower end thereof being at a height above and in the proximity of the surface of the melt in the crucible.