Point-contact (crystal) semiconductor device

摘要

794,843. Semi-conductor devices. STANDARD TELEPHONES & CABLES, Ltd. Oct. 28, 1955 [Nov. 4, 1954], No. 30893/55. Class 37. A point contact semi-conductor device comprises a conducting member closely surrounding the junction between the point contact and the semi-conductor body but insulated from both the point contact and the body. This member acts to reduce the interelectrode capacitance of the device and hence improves its high-frequency operation. In Fig. 1 the pointed wire 3, which is attached to Ni pin 2 by a pressuremoulded Pb or Pb alloy plug 5, contacts a Ge, Si or AISb alloy crystal 8 attached by welding, soldering or by a conductive cement, e.g. a polyethoxylene type cement containing Ag or AgSb alloy, to pin 6 which carries a similar plug 7. The two sub-assemblies are force-fitted into an unglazed non-porous tube 1 of glass, alumina, titania, or plastics, e.g. polymonochlorotrifluoroethylene and polytetranuoroethylene. An apertured disc 9 of Cu, CuSn alloy, Ni or Ag fits in slots in the tube 1. Wire 3 which may be of Pt, Wo, Ag, Pd, Au, Cu, Pt-Ru alloy, Ag-Sn alloy or phosphor bronze may be coated except at its tip by insulation, e.g. enamel and/or the disc 9 may be so coated around the aperture. Polyethoxylene resin 12 completes the assembly. Disc 9 may be earthed or maintained at such a potential as to accelerate or retard electrons injected into the crystal, being in the latter case earthed to A.C. by a capacitor. The disc may be foraminous, e.g. comprised of a screen of wires through one of the holes in which wire 3 passes. In a further alternative, Fig. 3, the disc is replaced by cone 19, the flange of which overlies the flanged end of the insulating tube, the pin carrying wire 20 being sealed through an insulating cap. In a further embodiment the pins bearing point contact and crystal respectively are mounted in glass, ceramic, polymonochlortrifluorethylene or polytetrafluorethylene plugs force-fitted in the ends of an earthed conductive tube formed at its centre with an inwardlyprojecting flange which closely surrounds the contact.