| 摘要 |
<p>959,608. Semi-conductor devices. SIEMENSSCHUCKERTWERKE A.G. Dec. 4, 1961 [Dec. 3, 1960], No. 43389/61. Heading H1K. In a process in which a number of members including one member of copper and one semiconductor member, are soldered or alloyed together, a powder is compressed around said parts, so as to ensure that substantially no copper vapour reaches the surface of the semiconductor member. As shown, assembly takes place in an iron container 1, the assembly consisting of a copper base-plate 2, a hard solder layer 3, a plate of molybdenum 4, an aluminium foil 5, a semi-conductor silicon body 6 and a gold-antimony foil 7. The silicon and molybdenum have the same coefficients of expansion, thus minimizing the stresses on the silicon. A packing of fine graphite powder 10 is then added and compressed by a loaded pressure plate 8, so that the powder penetrates into the very small clearance between the container and the plates 2, 4. The whole is then heated to provide the requisite alloying. The soldering of the members 1 and 2 may however be performed prior to their insertion in the container. During the heat treatment, electrodes are formed on the surface of the silicon and doping also takes place, as well as the other alloying processes. It is stated that copper vapour diffusing into the silicon tends to shortcircuit the PN-junctions so reducing their efficiency and that the diffusion is more pronounced where there are dislocations due to stress. To induce the effect of any copper vapour which may still penetrate the powder, the electrode bodies (which either consist of or contain doping material) are made of low volume and small thickness (e.g. about 70Á) to avoid said dislocations. The plate 4 may instead be of tantalum or tungsten and the semi-conductor may be germanium. The powder may instead by of magnesium oxide. The semi-conductor device may be a diode, transistor or a semi-conductor controlled rectifier.</p> |
