Verfahren zur Herstellung eines Stabes aus Halbleitermaterial

Pure silicon is deposited from a gas or vapour on to a rod of silicon containing phosphorus as doping agent to produce an enlarged rod of substantially known phosphorus content, whereafter the enlarged rod is subjected to zonemelting such a number of times and at such a speed of travel that a predetermined degree of evaporation and residual concentration of phosphorus is obtained. Half the total number of passages of the molten zone may be in one direction and the other half in the opposite direction. A seed crystal, which may be rotated, may be used to form a monocrystalline rod. The phosphorus-containing rod may be produced by deposition on a silicon carrier rod of a mixture of silicon and phosphorus from hydrogen containing vaporized phosphorus trichloride and silicochloroform with subsequent zone-melting and simultaneous stretching. An n-conducting rod having a resistivity of 100 ohm-cms may be produced from a polycrystalline rod having a resistivity of 10 ohm-cms by the passage of four molten zones at 3 mm per min, or five passages at 4 mm per min and a further one at 3,5 mm per min.