摘要 |
958,897. Extruding single crystals. RADIO CORPORATION OF AMERICA. April 6, 1961 [May 2, 1960], No. 12438/61. Heading B1S. A body 40 of molten germanium, which is contained in a variable volume cylinder 2 of carbon and is heated by an induction coil 10 is extruded through a die 6 of carbon or quartz as a monocrystalline strip 42, cooling being effected by streams of nitrogen issuing from pipes 24 and 26 at room temperature. The cylinder is operated by a piston 12. The strip is withdrawn between rollers 30 and 32 and may be wound on a reel. A single drive 33 operates both the piston and the rollers. The liquid-solid interface, which is initially formed by contacting the surface of the molten germanium with a seed crystal, is maintained within the die near the exit thereof. The streams of nitrogen may impinge on the centre of each side of the strip so as to form a downwardly extending concave interface. The dimensions of the strip may be 0À006Î0À156 inches. The strip may be withdrawn at a rate of 1 inch per minute. The dimensions may be reduced by increasing the rate of withdrawal. |