| 摘要 |
1,235,786. Resistive films. BENDIX CORP. 12 May, 1969 [4 June, 1968], No. 24097/69. Heading H1S. A method of preparing resistive films on a (glass) substrate 10 comprises vacuum depositing a first SiO coat 11; vacuum depositing to a predetermined sheet resistivity, a metal (e.g. Ni or Cr) film 14 which can react with SiO to form substances with higher resistivities than the metal; vacuum depositing a second SiO coat 16 over the metal film 14; and heattreating the resistive film so produced. Cr-Au terminals 12A, 12B are laid with the metal film. The resistance of the film is monitored and deposition is halted when the sheet resistivity is still above 6000 ohms per square for Ni, or 100,000 ohms per square for Cr. During the heat treatment the resistivity of the film rises due to reactions with the Si and 0; reactions with the atmosphere and substrate being prevented by the SiO layers 11, 16. The film may be heat-treated at a constant temperature between 206-400‹ C. for more than 30 minutes. Alternatively, comparison of the film resistance with a standard resistance may be used to increase the temperature until the film resistance reaches the desired value; or the film may be heated by D.C. current whilst its resistance is compared with a standard resistance in an A.C. bridge, the D.C. current being decreased as the bridge approaches a balanced state. Finally, the resistors are stabilized in air for at least 24 hours. |
