| 摘要 |
1,191,888. Semi-conductor devices. GENERAL ELECTRIC CO. 25 Sept., 1967 [12 Oct., 1966], No. 43607/67. Heading H1K. A sealed casing for a rectifying semi-conductor device 12 such as a diode or thyristor comprises two coaxially aligned insulating cylinders 34, 35 of equal internal diameter, joined by a conducting ring 33 of greater internal diameter, the inner walls of the cylinders 34, 35 being chamfered at 37 to minimize the risk of shorting. The ends of the cylinders 34, 35, which are preferably ceramic, are closed by terminal cups 13, 14 bonded thereto. As shown, the device 12 is a thyristor, the gate lead 27 being connected to the conducting ring 33. The device 12, which is pressure contacted between the W, Mo or Ni-plated Cu terminal cups 13, 14 by Cu pressure members 20, 21, using a silicone oil lubricant, comprises a Si wafer (22), Fig. 1a (not shown), mounted on a substrate (23) of W or Mo. An upper electrode (25) of Au is provided, and the lower surface of the substrate (23) has a bonded coating (24) of a predominantly noble metal, e.g. 94% Au/ 6% Ni. The coating (24) may consist of a series of discs of decreasing diameter further from the substrate (23), and since the assembly tends to bow during the mounting of the Si wafer (22) it is subsequently necessary to lap the major faces back to flatness. The sealed casing may be mounted in a finned pressure assembly as disclosed in Specification 1,191,887. |
