A CZ silicon ingot is doped with donors and acceptors and includes an axial gradient of doping concentration of the donors and of the acceptors. An electrically active net doping concentration, which is based on a difference between the doping concentrations of the donors and acceptors varies by less than 60% for at least 40% of an axial length of the CZ silicon ingot due to partial compensation of at least 20% of the doping concentration of the donors by the acceptors.

A CZ silicon ingot is doped with donors and acceptors and includes an axial gradient of doping concentration of the donors and of the acceptors. An electrically active net doping concentration, which is based on a difference between the doping concentrations of the donors and acceptors varies by less than 60% for at least 40% of an axial length of the CZ silicon ingot due to partial compensation of at least 20% of the doping concentration of the donors by the acceptors.

In a process for producing a silicon single crystal in which carbon is incorporated in order to inhibit crystal defects, provided is a process which easily allows carbon to be mixed and dissolved into a silicon melt. The process for producing a silicon single crystal, which involves allowing a silicon single crystal to grow during its pulling-up from the silicon melt held in a crucible, uses as at least part of a silicon raw material, crushed materials of a polycrystalline silicon rod produced by Siemens process that are obtained by crushing an end of the rod in the vicinity contacting a carbon core wire holding member.

The invention provides chunk polycrystalline silicon having a concentration of carbon at the surface of 0.5-35 ppbw. A process for cleaning polycrystalline silicon chunks having carbon contaminations at the surface, includes a thermal treatment of the polycrystalline silicon chunks in a reactor at a temperature of 350 to 600° C., the polycrystalline silicon chunks being present in an inert gas atmosphere during the thermal treatment, and the polycrystalline silicon chunks after the thermal treatment having a concentration of carbon at the surface of 0.5-35 ppbw.

The invention provides chunk polycrystalline silicon having a concentration of carbon at the surface of 0.5-35 ppbw. A process for cleaning polycrystalline silicon chunks having carbon contaminations at the surface, includes a thermal treatment of the polycrystalline silicon chunks in a reactor at a temperature of 350 to 600° C., the polycrystalline silicon chunks being present in an inert gas atmosphere during the thermal treatment, and the polycrystalline silicon chunks after the thermal treatment having a concentration of carbon at the surface of 0.5-35 ppbw.

Systems and methods for continuous sapphire growth are disclosed. One embodiment may take the form of a method including feeding a base material into a crucible located within a growth chamber, heating the crucible to melt the base material and initiating crystalline growth in the melted base material to create a crystal structure. Additionally, the method includes pulling the crystal structure away from crucible and feeding the crystal structure out of the growth chamber.

A sheet-forming apparatus including a crucible for holding a melt of material and a solid sheet of the material disposed within the melt, a crystallizer disposed above the crucible and configured to form the sheet from the melt, and an ultrasonic measurement system disposed adjacent the crystallizer, the ultrasonic measurement system comprising at least one ultrasonic measurement device including a waveguide coupled to an ultrasonic transducer for directing an ultrasonic pulse through the melt.

A system for growing silicon crystal structures includes a housing defining a growth chamber and a feed system connected to the housing for delivering silicon particles to the growth chamber. The feed system includes a container for holding the silicon particles. The container includes an outlet for discharging the silicon particles. The feed system also includes a channel connected to the outlet such that silicon particles discharged from the container flow through the channel. The feed system further includes a separation valve connected to the channel and to the housing. The separation valve is configured such that a portion of the feed system rotates relative to the housing.

The present invention relates to a Czochralski growth apparatus and method, preferably a continuous Czochralski growth apparatus and method, in which solid feedstock provided from a delivery system during ingot growth is substantially prevented from entering the growth zone of a crucible. In this way, an ingot having exceptionally consistent properties is produced.

After determining the size of oxygen precipitates and the residual oxygen concentration in a silicon wafer after heat treatment performed in a device fabrication process; the critical shear stress τ.sub.cri at which slip dislocations are formed in the silicon wafer in the device fabrication process is determined based on the obtained size of the oxygen precipitates and residual oxygen concentration; and the obtained critical shear stress τ.sub.cri and the thermal stress τ applied to the silicon wafer in the heat treatment of the device fabrication process are compared, thereby determining that slip dislocations are formed in the silicon wafer in the device fabrication process when the thermal stress τ is equal to or more than the critical shear stress τ.sub.cri, or determining that slip dislocations are not formed in the silicon wafer in the device fabrication process when the thermal stress τ is less than the critical shear stress τ.sub.cri.