Verfahren zum gezielten Einbringen von Fremdstoffen in Halbleiterkristalle

摘要

1,152,415. Doping and the like. SIEMENSA.G. 6 Jan., 1967 [7 Jan., 1966], No. 899/67. Heading B1S. In the zone-melting or crystal-pulling of silicon in a vacuum chamber, a desired impurity (or decomposable compound thereof) is supplied in the gas phase at a controlled rate to molten silicon near the solidifying interface. The impurity may be contained in a carrier gas, e.g. as a boron trichloride/hydrogen, trimeric phosphorus chloride nitride/air, or gold chloride/chlorine mixture. As shown, a molten zone 8 is passed through a rod 3, by means of an induction coil 6, in an evacuated chamber 2, the pressure of which is maintained constant and an impurity is supplied to the molten zone via a pipe 10 of chromium-nickel steel or aluminium and a valve 15 from a storage chamber 11 maintained at a constant temperature and pressure. Pipe 10 may be movable and may support the induction coil. The vacuum chamber may have a pressure of less than 10-4mm Hg and the storage vessel may have a pressure of 10-3 to 1 mm Hg.