| 摘要 |
983,146. Semi - conductor devices. STANDARD TELEPHONES & CABLES Ltd. Aug. 25, 1961 [Aug. 30, 1960], No. 29818/60. Heading H1K. Semi-conductor devices include an effectively non - conducting support having a planar surface on which are two sideby - side semi - conductor layers of opposite conductivity type arranged in edge to edge contact to form a PN junction between them, the width of the junction being less than that of the support in the junction region. The embodiments described make use of a high resistivity intrinsic semi-conductor material such as silicon as the effectively non-conducting support but the use of ceramics and other materials is envisaged. In constructing semi-conductor diodes P and N-type layers 2 and 3 are formed on a disc 1 of high resistivity silicon (Fig. 2) either by solid state diffusion or by a deposition process such as epitoxial growth. Strips which are to form separate diodes are cut from the disc and portions of the doped layers are removed to expose parts 1a of the support surface and thus reduce the junction area. A coating 5 (Fig. 7) of a metal such as aluminium is then applied over most of the surface of the P and N layers leaving only the region in the vicinity of the junction uncovered. Silver layers 6 are then provided at the ends of the metal coating and the diode placed in a two-part metal tube 7, of e.g. Ni/Fe alloy, whose halves are joined by a glass bead 8 exposing the diode junction. Solder 9 is applied to seal the tube and to contact the silver layers of the varactor diode which is then suitable for insertion into a waveguide. Simulated point contact diodes are described in Figs. 8 and 9 (not shown) in which oxide masking of the support is used to limit the area of deposition of the P and N layers where the junction is to be formed. The diode of Fig. 9 (not shown) has its N-type layer produced by diffusion on the surface of the intrinsic silica support while its P-type layer is produced by evaporation and alloying of e.g. A1/B. Tunnel diodes may be made like the diode of Fig. 7 but using very high doping of the P and N layers, while transistors may be formed by having three layers side by side on the support. |
