Semiconductor acceleration sensor with movable electrode
First Claim
1. A semiconductor acceleration sensor comprising:
- a semiconductor substrate;
a beam structure supported by said semiconductor substrate and having a electrode disposed at a predetermined interval above said semiconductor substrate;
fixed electrodes disposed on said semiconductor substrate and provided with respect to said movable electrode so that a sensing portion is constituted by said movable electrode and said fixed electrodes and acceleration is detected by changes in current between said fixed electrodes generated by means of a displacement of said movable electrode caused by an acceleration on said sensing portion; and
an electrode for movable electrode upward-movement use disposed at a height at least equal to a height at which said movable electrode is disposed, said electrode for movable electrode upward-movement use being given a potential difference against said movable electrode so as to counteract an attractive force of said movable electrode toward said semiconductor substrate,wherein said electrode for movable electrode upward-movement use includes an impurity diffusion layer formed on a high-resistance silicon substrate disposed above said movable electrode, said impurity diffusion layer opposing said movable electrode.
1 Assignment
0 Petitions
Accused Products
Abstract
Adverse effects due to electrostatic force between a semiconductor substrate and a movable electrode are avoided with a new structure. A movable electrode of beam structure is disposed at a specified interval above a p-type silicon substrate. Fixed electrodes, each composed of an impurity diffusion layer, are disposed on both sides of the movable electrode on the p-type silicon substrate; these fixed electrodes are self-aligningly with respect to the movable electrode. The movable electrode is displaced in accompaniment to the action of acceleration, and acceleration is detected by change (fluctuation) in current between the fixed electrodes generated by means of this displacement. Additionally, an electrode for movable electrode upward-movement use is disposed above the movable electrode, a potential difference is given between the movable electrode and the electrode for movable electrode upward-movement use, and attractive force of the movable electrode to the silicon substrate is alleviated.
-
Citations
65 Claims
-
1. A semiconductor acceleration sensor comprising:
-
a semiconductor substrate; a beam structure supported by said semiconductor substrate and having a electrode disposed at a predetermined interval above said semiconductor substrate; fixed electrodes disposed on said semiconductor substrate and provided with respect to said movable electrode so that a sensing portion is constituted by said movable electrode and said fixed electrodes and acceleration is detected by changes in current between said fixed electrodes generated by means of a displacement of said movable electrode caused by an acceleration on said sensing portion; and an electrode for movable electrode upward-movement use disposed at a height at least equal to a height at which said movable electrode is disposed, said electrode for movable electrode upward-movement use being given a potential difference against said movable electrode so as to counteract an attractive force of said movable electrode toward said semiconductor substrate, wherein said electrode for movable electrode upward-movement use includes an impurity diffusion layer formed on a high-resistance silicon substrate disposed above said movable electrode, said impurity diffusion layer opposing said movable electrode. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
2. A semiconductor acceleration sensor comprising;
-
a semiconductor substrate; a beam structure supported by said semiconductor substrate and having a movable electrode disposed of a predetermined interval above said semiconductor substrate; fixed electrodes disposed on said semiconductor substrate and provided with respect to said movable electrode so that a sensing portion is constituted by said movable electrode and said fixed electrodes and acceleration is detected by changes in current between said fixed electrodes generated by means of a displacement of said movable electrode caused by an acceleration on said sensing portion; and an electrode for movable electrode upward-movement use disposed at a height identical to a height at which said movable electrode is disposed, said electrode for movable electrode upward-movement use being given a potential difference against said movable electrode so as to counteract an attractive force of said movable electrode toward said semiconductor substrate. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
-
27. A semiconductor acceleration sensor comprising:
-
a supporting substrate; a beam structure supported by said supporting substrate and having a movable electrode disposed above said supporting substrate of a predetermined interval; an acceleration detector for detecting an acceleration applied to said sensor based on a displacement of said movable electrode displaced along a horizontal direction with respect to said supporting substrate; and a control electrode disposed at a height of at least equal to a height at which said movable electrode is disposed, said central electrode being located relative to said movable electrode and a potential being applied thereto for causing an electrostatic force to act on said movable electrode so as to keep said predetermined interval between said movable electrode and said supporting substrate constant. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35)
-
-
36. A semiconductor acceleration sensor comprising:
-
a supporting substrate; a beam structure supported by said supporting substrate at least at three anchor potions at corner portions thereof and having a movable electrode disposed above said supporting substrate at a predetermined interval; an acceleration detector for detecting an acceleration applied thereon based on a displacement of said movable electrode due to an acceleration, applied thereto said displacement of said movable electrode being perpendicular to said supporting substrate; and a control electrode disposed at a height at least equal to a height at which said movable electrode is disposed, said control electrode being located relative to said movable electrode and a potential being applied thereto for causing an electrostatic force to act on said movable electrode so as to cancel out an attractive force of said movable electrode toward said supporting substrate. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45)
-
-
46. A semiconductor acceleration sensor comprising:
-
a supporting substrate; a beam structure supported by said supporting substrate and having a movable electrode disposed above said supporting substrate at a predetermined interval; an acceleration detector for detecting an acceleration applied thereon based on a displacement of said movable electrode due to an acceleration, said acceleration detector including an insulated gate type field effect transistor structure which is formed between said movable electrode and said supporting substrate; and a control electrode provided at a portion other than under said movable electrode on said supporting substrate and to which is applied a constant voltage for cancelling out an attractive electrostatic force acting between said movable electrode and said supporting substrate during a period wherein said insulated gate type field effect transistor structure is turned on. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65)
-
Specification