| 摘要 |
1,169,726. Semi-conductor devices. TEXAS INSTRUMENTS Inc. 16 Dec., 1966 [6 Jan., 1966], No. 56448/66. Heading H1K. A rectifying contact is made between a metal electrode 17 and a relatively low impurityconcentration zone 18 of a single conductivitytype monocrystalline semiconducting region provided in the surface of a high-resistivity dielectric substrate 10. An ohmic contact is provided between a second metal electrode and a high impurity-concentration zone of the same semi-conducting region. In the embodiment shown the substrate 10 is formed of highresistivity Si, with the low impurity-concentration zone 18 being produced therein by phosphorus diffusion through an oxide mask 11. Two spaced high-impurity concentration zones 24, 25 are diffused on either side of the zone 18, and electrodes 17, 20, 21 are provided by evaporation or sputtering of Mo followed by sputtering of Au. The electrode 17 forms a rectifying contact while the electrodes 20, 21 form ohmic contacts, the difference being due to the different impurity concentrations in the respective zones. A further metal layer 15 of Au, Al or Mo and Au is deposited on the back of the substrate 10, and forms a ground plane for a microstrip transmission line constituted by the metal electrodes 17, 20/21 and the dielectric substrate 10. In a microwave mixer circuit described in the Specification two rectifying-barrier diodes are formed in the same substrate. Other devices such as transistors, resistors, and inductors may also be integrated with a diode according to the invention. The high- and low-impurity concentration zones may both be formed in a single diffusion step, due to the lateral diffusion which occurs under an oxide mask defining the area of the high concentration zone. A contact made through an aperture formed in the mask above a peripheral portion (49), Fig. 9 (not shown), of the diffused region will encounter relatively low impurity-concentration material and will be rectifying, while a contact applied to the central portion (47) of the region will be ohmic. In an alternative manufacturing method the active zones are formed by epitaxial deposition of material into shallow recesses etched in the substrate through a Si 3 N 4 mask. In this method a relatively high impurity-concentration layer may first be deposited, followed by a lower concentration layer. Both active and dielectric parts of the structure may be of GaAs, the substrate containing Fe or Cr deep level impurities, and combinations of Ge with a semi-insulating GaAs substrate or Si with a semi-insulating GaP substrate are also referred to. The substrate may also be of polycrystalline, ceramic or epoxy material deposited over mesas formed on a monocrystalline wafer, the wafer then being lapped away to leave only the spaced mesa portions supported by the substrate. |
