| 摘要 |
<p>PURPOSE: To provide a semiconductor dynamic-quantity sensor which is small and whose sensitivity is high. CONSTITUTION: A ring-shaped groove 2 is formed on a silicon substrate 1, and a cavity part 3 is formed in a region surrounded by the groove 2. Beam parts 5, 6, 9, 10, 11, 12 which are composed of a polysilicon thin film are installed so as to be extended to the cavity part 3 from the surface of the silicon substrate 1. In the cavity part 3, a weight part 4 which forms a part of the silicon substrate 1 is supported by the beam parts 5, 6, 9, 10, 11, 12. The weight part 4 is displaced to a direction parallel to the surface of the silicon substrate 1 due to the action of an acceleration. A beam part 17 is constructed on the surface of the weight part 4 by keeping a prescribed interval. Source electrodes 19, 21 and drain electrodes 20, 22 are formed in the weight part 4 at the lower part of the beam part 17. When the weight part 4 is displaced, an overlap area (a channel wodth) with the beam part 17 for a gate electrode between the sources and the darins is changed. The acceleration is detected on the basis of it.</p> |
