| 摘要 |
PURPOSE:To raise the self-diagnosing signal outputting level of an acceleration sensor and improve the responsiveness of the sensor by forming through holes in one electrode and providing air damping reducing grooves formed through the through holes by etching in a semiconductor section. CONSTITUTION:Of metallic electrodes 7 and 9 for self-diagnosis, the electrode 7 on a silicon pedestal 5 side has through holes 9 arranged in a plurality of rows. Air damping reducing grooves 10 having end sections opened on the outside of both end edges of the electrode 7 are formed in a semiconductor section which is in contact with the electrode 7. Since the effective area of the electrode 7 which contributes to the impression of an electrostatic force at the time of self-diagnosis is such that the areas of the holes 9 are negligibly small as compared with the whole overlap area of the electrodes 7 and 8 while the areas of the holes 9 are invalid, the self-diagnosing signal of this acceleration sensor is maintained at a high output level. At the time of detecting acceleration, an overlapping section 3 is displaced and a gas in an air gap enters the grooves 10 through the holes 9 and goes out from the openings 10a of the grooves 10. Therefore, air damping is relieved and the responsiveness of the sensor is improved. |
