| 摘要 |
PURPOSE:To prevent frequency drift with a variable capacity fixed by grounding or fixing to the potential of power supply that of an isolation under a junction pad. CONSTITUTION:A P<+> islation layer 7 is made under an oxide film 4 provided under a junction pad 5 and a low impedance is provided between the layer 7 and a substrate 1. Therefore, isolation potential is fixed on grounding (substrate 1), or an N<+> layer 8 is provided to extend to an N<-> layer through the film 4 and connected to a power source. Thereby, if a high-frequency oscillation circuit is made of IC, the potential of the isolation under the pad 5 does not change so that frequency drift considerably decreases immediately after power supply. |
