Verfahren zur Oberflächenbehandlung von Halbleiteranordnungen

摘要

932,349. Surface treatment of PN junction rectifiers. SIEMENS-SCHUCKERTWERKE A.G. Jan. 26, 1962 [Jan. 27, 1961 (2)], No. 3141/62. Class 37. The exposed surface of a PN junction in a semi-conductor device is etched and then exposed to the vapour formed above a liquid consisting of nitric acid and hydrofluoric acid until a thin layer is formed over the exposed portion of the junction the thickness of the layer being such that it exhibits the colour of a thin plate. In the described embodiment a P-type silicon disc has an ohmic electrode comprising a gold foil disc containing 0.3% boron alloyed to one face and a PN junction formed by a gold foil disc containing 0.5% antimony alloyed to the other face, the alloying taking place whilst the assembly of discs is embedded under pressure in an inert powder. The PN junction is then etched, e.g. on an etching centrifuge in which the disc is rotated about its axis of symmetry whilst it is sprayed with etchant, after which the device is rinsed in water and exposed to the vapour of a nitric and hydrofluoric acid mixture. If desired the rectifier element may then be tempered for 24 hours at 200-300‹ C. then again etched and exposed to the vapour.