| 摘要 |
827,117. Semi-conductor devices. STANDARD TELEPHONES & CABLES Ltd. Jan. 3, 1958, No. 332/58. Class 37. [Also in Group II] A junction transistor comprises first, second and third layers of polycrystalline semi-conductor material the conductivity types of which are different from layer to layer and a film of polycrystalline insulating or intrinsic semi-conducting material between the first and second layers. In one embodiment a PNIP transistor is made by the following steps. A layer P1 of polycrystalline P-type silicon is formed on a goldplated copper collector plate 1 by deposition in vacuum from the mixed vapours of intrinsic silicon and an acceptor impurity, e.g. indium. A layer 1 of the intrinsic silicon alone is then deposited on layer P1 followed by a layer N of N-type silicon of smaller extent deposited from the mixed vapours of silicon and a donor impurity, e.g. antimony. A gold-plated metal lug is placed on the N-type layer and a ring of gold evaporated on the layer and extending over the lug to provide a base contact. After a layer 11 of insulating material has been applied to the assembly as shown a further layer P2 of polycrystalline P-type silicon is evaporated as before, on to the exposed surface of the N-type layer. An emitter contact is provided to this layer by evaporating a gold layer thereon and then welding a gold-plated contact 13 to it by passing a heavy current through the contact. A protective layer of insulating material such as magnesium fluoride may be applied to the finished device leaving parts of the base, emitter and collector contacts exposed. A thin layer of normally insulating material such as magnesium fluoride may replace the intrinsic silicon layer in the above device. In the above described vacuum deposition processes, in which germanium may be used in place of silicon, the mixed vapours are produced by simultaneous evaporation of the component materials from separate containers. The position and extent of the evaporated layers are controlled by the use of suitably shaped masks. A number of devices may be made in a single process on a single gold-plated copper plate 1 provided with a series of intersecting grooves. The plate is afterwards broken along the cuts into a number of single units. |
