| 摘要 |
This invention discloses an acceleration sensor, in which reliable insulation is provided between a movable electrode and a fixed electrode, so that influences of noise is reduced to improve detection accuracy and detection sensitivity of acceleration. A lower substrate (2) made of an insulating material is disposed on the lower surface side of an upper substrate (1) made of a silicon material having a small resistivity, and an insulating trench (5) penetrating through the upper substrate (1) from its upper surface side to its lower surface side is disposed in the upper substrate (1) throughout the periphery of a support beam (4). Accordingly, the support beam (4) and each fixed portion (6) opposing the support beam (4) are separated from each other using the upper substrate (1). As a result, the support beam (4) having a low resistance and each fixed portion (6) are electrically insulated from each other by the insulating trench (5). A mass portion (4C) forms a movable electrode and each fixed portion (6) forms a fixed electrode. When the mass portion (4C) undergoes displacement in accordance with acceleration, the change of the electrostatic capacitance between the electrodes is outputted as an acceleration signal. |
