IMPROVEMENTS IN OR RELATING TO THE PRODUCTION OF P-DOPED ZONES IN SEMICONDUCTOR MONOCRYSTALS

摘要

1,241,397. Semi-conductor devices. SIEMENS A.G. 16 April, 1970 [17 April, 1969], No. 18088/70. Heading H1K. A P-doped zone is produced in a N-type germanium crystal by masking the crystal surface with aluminium oxide by pyrolysis of an organic compound of oxygen and aluminium. A chemically polished germanium crystal is supported in a reaction vessel and is rotated by a motor in a stream of vaporized aluminium isopropylate, secondary butylate, or acetyl acetonate in a carrier gas, e.g. argon or nitrogen; the proportions of gas and vapour being controlled by flow meters; and the crystal is HF heated, so that decomposition of the organic compound produces a layer of amorphous aluminium oxide on the crystal (Fig. 1, not shown). A window is photo-etched therein using hot concentrated phosphoric acid, a gallium dopant is diffused therein, and the remaining aluminium oxide is etched off using hot concentrated phosphoric acid (Fig. 2, not shown). The process is applicable to double diffused germanium, silicon, and AIIIBV semi-conductor crystals.