| 摘要 |
732,797. Coating by vapour deposition. TELEFONAKTIEBOLAGET L. M. ERICSSON. Sept. 29, 1952 [Jan. 22, 1952], No. 24374/52. Class 82 (2). [Also in Group XXXVI] One or more semi-conductive layers of germanium containing small amounts of other elements are formed by evaporating pure germanium and the other elements and condensing them, under low pressure, on a support. Semi-conductive layers may be deposited on a copper or nickel plate 18, Fig. 1, by vaporizing germanium in a corundum-lined crucible 11 and another element, e.g. antimony or aluminium, in a crucible 14; 13 and 15 are screens, the latter being rotatable about its axis by magnetic means 17; the plate 18 is heated by an H.F. coil 19 to 350-500‹ C. The semi-conductive properties may be controlled in accordance with measurements of the Hall coefficient of a deposit formed simultaneously on an insulating plate, and the thickness of the layer in accordance with light-absorption measurements on a simultaneously coated glass plate. After deposition, the layers are heated at 400‹ C. for 10 minutes and the temperature then lowered by 100‹ C. steps at 5-minute intervals. In the apparatus of Fig. 2, three layers are deposited on mica plates 22: germanium is contained in the crucible 11 and aluminium and antimony are evaporated from bands 20, 21 of tungsten or tantalum coated therewith. In addition to the magnetically operated screen 15, a magnetically operated masking screen 24 is provided, with apertures so arranged that deposits 31, 32, 33, Fig. 3, may be formed on the mica sheets, 31, 33 being Ge-Sb and 32 Ge-Al. Alternatively, layers of germanium and impurity elements may be deposited separately and the impurity diffused into the germanium by heat treatment. |
