| 摘要 |
979,990. Semi-conductor devices. GENERAL ELECTRIC CO. March 21, 1963 [March 23, 1962], No. 11233/63. Heading H1K. A semi-conductor device comprises a body of semi-conductor material having a pair of spaced base electrodes of different contact area, and a zone of opposite conductivity type adjacent the smaller base electrode forming a PN junction with the body. The device may comprise a unijunction transistor wherein most of the resistance in the body between the two base electrodes is adjacent the smaller electrode, allowing the closer spacing therefrom of the control PN emitter junction and electrode, and thus providing a shorter turn-on time, a higher stand-off ratio and a lower emitter saturation voltage. The unijunction transistor may comprise, Fig. 1, fernico conductive member 8 having two openings through which extensions 3 of a glass insulating base extend. Leads 4 and 5 extend through the glass base and the openings and are respectively connected to leads 11 and 12. A third lead 6, is connected to member 8. A slab of N-type semi-conductor 10 is soldered by a gold/antimony alloy to the gold-plated surface of member 8, thus forming a large area base contact, having a lead 6. Lead 11 is also of the gold/antimony alloy and forms a second small area base contact with slab 10. Lead 12 is of aluminium and forms a rectifying contact with the slab 10. Leads 11 and 12 are fused to the slab by the passage of large current pulses. A cap 2 is provided. The rectifying contact may be made to the side of the slab, Fig. 4 (not shown). Alternatively the slab 20, Figs. 5 and 6, may be formed with an etched base 21, having the smaller base electrode 22 connected to the bottom thereof. The large area base contact 24 is made to the other side of the slab, the leads thereto also serving to support the slab, and the rectifying contact 23 is also made to the other side of the slab, opposite the positions of contact 22. A layer of semi-conductive material may be applied by diffusion or epitaxial growth to the upper surface of the slab 20, of lower resistivity than the slab, but of the same type of conductivity and having a thickness less than the spacing between contacts 22 and 23. |
