TRANSISTORS AND HEADERS

1,200,375. Semi-conductor devices. TEXAS INSTRUMENTS Ltd. 15 Sept., 1967, No. 42216/67. Heading H1K. The base lead 7 to a transistor wafer 10 has a greater transverse dimension than at least the emitter lead(s) 8, thereby reducing the base lead inductance. In the embodiment the wafer 10 is bonded by its collector region to a metallized area 2 on an insulating support, the collector lead 6, which is bonded to and cantilevered from this area 2, being of the same transverse dimension as the base lead 7. Further metallized areas 3, 4 respectively carry the base and emitter leads 7, 8, Au wires 11, 12 being provided to connect the areas 3, 4 to the relevant regions of the wafer 10. The areas 2-4 are of Ni overlaid with Au, while the leads 6-8 are of Au-plated Cu. If desired, only one emitter lead 8 may be provided, and the two opposed parts of the area 4 may be separated instead of being linked as shown. The device is encapsulated in silicone potting compound 13, apertures 14 in the leads 6, 7 improving the strength of the package. Alternatively, transversely spaced longitudinal slits defining intermediate regions which are displaced relative to the plane of the leads may be provided in the embedded parts of the leads 6, 7 as described in Specification 1,193,519.