| 摘要 |
PURPOSE:To detect correct capacitance by making equal a potential on both faces of a movable electrode facing two fixed electrodes in a capacitance-type semiconductor acceleration sensor and a pressure sensor of a differential struc ture comprising the two fixed electrodes and one movable electrode. CONSTITUTION:An n-layer 38 used as an etch-stop layer lies over a p-region 37 of a sensor body 32, while a p<+>-layer 39 lies over the n-layer 38. The p<+>-layer 39 is formed through an upper face of a beam 36 from an entire face of a weight 35 to an upper face of a support frame 33. On the upper face of the weight 35, the p<+>-layer 39 passes through the n-layer 38 to directly join with the p-region 37, while an electrode 40 is provided on the p<+>-layer 39 on the upper face of the support frame 33. Fixed electrodes 112 face both upper and lower faces of the weight 35 being a movable electrode. Potential on an upper face 41a of the movable electrode (p<+>-layer 39) and a lower face 41b of the movable electrode (a lower face of the p-region 37) is extracted to the electrode 40 without passing through a pn junction. |
