| 摘要 |
895,326. Semi-conductor rectifiers. GENERAL ELECTRIC CO. Ltd. June 10, 1959 [June 18, 1958], No. 19478/58. Class 37. In a semi-conductor device of the kind in which one portion of a semi - conductor body is in good electrical and thermal contact with a metallic part of an envelope, which encloses the said body and is adapted to be maintained in good thermal contact with a metallic member outside the envelope, the lead for a second portion of the said body includes a relatively massive part disposed inside the envelope and in good thermal contact with said second portion. As shown, a rectifier for use with low-frequency A.C. comprises a wafer 1 of P-type silicon, of which one surface is doped with boron to produce a low resistivity P-type region, and the opposite surface is doped with phosphorus to produce a region of N-type conductivity, each surface being subsequently plated with nickel and then vapour-coated with gold. The diode thus formed is mounted between two cylindrical copper blocks 3, 13, the contact surfaces of which are coated with gold, a lead disc being interposed between the diode and each copper block and soldering being effected by heating the assembly at 400‹ C. in a nitrogen atmosphere, a wire 15 having been previously brazed to the base of a central conical recess 18 in the block 13. The exposed portions of the diode are then coated with silicone resin which is heat cured, after which a copper cap 4, into which a copper tube 12 to accommodate wire 15 is sealed through a glass bead 11, is placed over the diode and the block 13, and flanges 5, 6, on block 3 and cap 4, respectively, are sealed by cold welding in a nitrogen atmosphere. A threaded stub 7 at the end of block 3 remote from the diode facilitates its clamping to a metallic cooling- member 8. Specification 817,636 is referred to. |
