Abstract:
1,065,531. Transistors. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. March 29, 1964 [March 29, 1963], No. 7584/64. Heading H1K. In a junction transistor in which the base zone occupies only a limited part of the body cross-section the emitter zone is in an elongated recess in a base contact layer which substantially surrounds it, the layer being widened at the point at which a supply conductor is secured to it. The recess and the widened part of the base contact layer are preferably the same shape and size and may be arranged with their longitudinal dimensions in line, as in Figs. 6, 7, 8 and 11 (not shown), mutually perpendicular as in Fig. 5 (not shown) or side by side as in Figs. 1, 3 and 4 (also not shown). The recess is typically oval, rectangular or semi-circular. Preferably the supply conductors are thermocompression bonded to the emitter zone and base contact layer by means of a pressure chisel. In this case although the bonded area extends mainly in the direction of elongation of the chisel i.e. at right angles to the axis of the wire the maximum spread of wire material over the contacted surface is along the axis of the wire. Therefore generally the wires are arranged with their axes along the longitudinal direction of the recess and widened part of the base contact layer. If, however, short-circuiting of the emitter-base junction as a result of this spread is prevented, as by an oxide film on the semi-conductor or base contact material the wires may have their axes perpendicular to this. In a typical NPN germanium transistor, Fig. 2, the base zone is formed by diffusion into an N-type wafer from an indium-germanium source. An evaporated base contact 6 of aluminium indium alloy is alloyed to it and the emitter zone 5 then formed by diffusion from arsenic vapour. The layers are finally reduced to mesa form by etching. In an alternative method the emitter diffusion precedes formation of the base contact.
Abstract:
1,010,698. Semi-conductor devices. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. Jan. 11, 1963 [Jan. 15, 1962], No. 1376/63. Heading H1K. In a method for soldering a connecting wire to a semi-conductor body or alloyed electrode thereof, the wire is held in place only by a magnetic field during the soldering operation. The Figure shows a germanium wafer 1 with alloyed electrodes 2 of lead and antimony on a carbon support 3 located between magnetic polepieces 6 and 7. The block is heated by radiation from lamp 8 and at the soldering temperature gold-plated nickel wires 4 which are held in place by the magnetic field are soldered to electrodes 2. Other means of heating may be employed such as hot gas or a heating coil; the process is particularly suitable for mass production of transistors.
Abstract:
899,997. Semi-conductor devices. PHILIPS ELECTRICAL INDUSTRIES Ltd. Nov. 3, 1958 [Nov. 5, 1957], No. 35207/58. Class 37. Semiconductor devices are manufactured by securing a semiconductor wafer, to a plurality of supports and then breaking the wafer between the supports to form a plurality of bodies each mounted on a support. The wafer 1 may be secured to the fingers of a comb 3 as in Fig. 2, and emitter 5 and base 6 electrodes provided before cutting the support along lines 8 and breaking the wafer between the fingers to provide a plurality of transistors. Alternatively a wafer 23 may be soldered to the ends of a series of supports clamped together in a stack 20 (Fig. 4), broken along lines 24 to provide a number of elements each comprising a line of support elements which is then broken again to provide the plurality of separate elements each bearing a piece of the wafer. The semi-conductor may consist of germanium and the supports of nickel.