Abstract: A process and an apparatus control the growth of a crystal, which growth is governed by a set of measurable and non-measurable variables. The process includes establishing an on-line simulation software working with a reduced number of variables, the reduction of variables being performed by using a projection algorithm; speeding up the on-line simulation software by generating data banks in which values of off-line precalculated variables are stored; tuning the on-line simulation software by adjusting the results predicted by on-line simulations to the results obtained by off-line simulations and by measurements; and establishing a control loop and controlling at least one of the variables in real time, the control loop using the speeded up and tuned on-line simulation software as an on-line observer.

Abstract: A method and an apparatus for pulling a silicon monocrystal from a melt iudes the pulling of a conical portion in each case at the beginning and at the end of the monocrystal and the pulling of a cylindrical portion between the conical portions. In this method, the surface of the conical portion at the beginning of the monocrystal is shielded by a shielding means spaced apart from the monocrystal.

Abstract: A method and a device is provided for determining the diameter of a monocrystal growing at a crystallization boundary during the pulling of the monocrystal from a melt. The method includes imaging a part of the crystallization boundary on at least one mirror, observing the mirror image and determining the diameter of the monocrystal from the observed relative position of the crystallization boundary on the mirror image.

Abstract: Apparatus for producing a single crystal of semiconductor material in accance with the Czochralski method, has a cooling means which cools the growing single crystal and is constructed in two parts, The first is an upper part duct system through which a liquid coolant flows. The second is a lower part which is a heat-conducting cooling body.

Abstract: A method for pulling a silicon single crystal has the single crystal being pulled at a speed defined as maximum pulling speed in the vertical direction with respect to a silicon melt held in a crucible. The value of the maximum pulling speed is approximately proportional to the axial temperature gradient in the growing single crystal.

Abstract: Silicon ingots, in particular, with diameters of approximately 75 mm and greater, can be produced by zone pulling with an oxygen content comparable to crucible-pulled material if a flat quartz element is brought into contact with the molten cap during the pulling operation. A quartz ring which is arranged concentrically beneath the induction heating coil and can be lowered from a rest position into its working position on the molten cap is suitable as a flat element. The ingot material obtained in this manner and also the silicon wafers produced therefrom combine the purity advantages of zone-pulled silicon with the beneficial gettering and hardening action of the incorporated oxygen which otherwise distinguishes only crucible-pulled silicon.

Abstract: An induction heating coil for a zone pulling of semiconductor rods assures the disturbance-free performance of the pulling process even at the high power densities required for large rod diameters (approximately 10 to 12 cm). According to the invention, the arc-over paths between surfaces in the region of the coil slot, which are at differing potentials, are covered by one or more movable planar structures of temperature-stable insulating material which are introduced into the coil slot.