Semiconductor dynamic sensor having variable capacitor formed on laminated substrate
First Claim
1. A semiconductor dynamic sensor formed on a laminated substrate composed of a base substrate, an insulation layer and a thin semiconductor layer, laminated in this order, the semiconductor dynamic sensor comprising:
- a first capacitor including a first beam structure formed on the thin semiconductor layer, the first beam structure having first beams and a first movable electrode supported by the first beams and facing the base substrate with an air gap therebetween, so that the first movable electrode moves in a direction perpendicular to the surface of the thin semiconductor layer when a dynamic force is imposed on the first movable electrode while a first carrier voltage is being applied thereto, a first capacitance being formed between the first movable electrode and the base substrate; and
a second capacitor including a second beam structure formed on the thin semiconductor layer, the second beam structure having second beams and a second movable electrode supported by the second beams and facing the base substrate with an air gap therebetween, so that the second movable electrode moves in a direction perpendicular to the surface of the thin semiconductor layer when a dynamic force is imposed on the second movable electrode while a second carrier voltage is being applied thereto, a second capacitance being formed between the second movable electrode and the base substrate, wherein;
the first capacitance varies according to the dynamic force applied to the first movable electrode, and the second capacitance varies, in a manner different from the first capacitance, according to the dynamic force applied to the second movable electrode; and
an output signal representing a capacitance difference between the first capacitance and the second capacitance is taken out from the base substrate.
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Accused Products
Abstract
An acceleration sensor is formed on a top surface of a laminated silicon-on-insulator substrate. The acceleration sensor is composed of first and second capacitors each including a movable electrode that moves according to acceleration imposed thereon. The first and the second capacitors are so made that their capacitances change differently when the same acceleration is imposed and that the capacitance difference represents an amount of acceleration imposed thereon. A third capacitor having an output electrode solidly connected to the base substrate via the insulation layer is also formed on the same silicon-on-insulator substrate. An output representing amount of acceleration is taken out from the output electrode of the third capacitor.
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Citations
13 Claims
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1. A semiconductor dynamic sensor formed on a laminated substrate composed of a base substrate, an insulation layer and a thin semiconductor layer, laminated in this order, the semiconductor dynamic sensor comprising:
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a first capacitor including a first beam structure formed on the thin semiconductor layer, the first beam structure having first beams and a first movable electrode supported by the first beams and facing the base substrate with an air gap therebetween, so that the first movable electrode moves in a direction perpendicular to the surface of the thin semiconductor layer when a dynamic force is imposed on the first movable electrode while a first carrier voltage is being applied thereto, a first capacitance being formed between the first movable electrode and the base substrate; and
a second capacitor including a second beam structure formed on the thin semiconductor layer, the second beam structure having second beams and a second movable electrode supported by the second beams and facing the base substrate with an air gap therebetween, so that the second movable electrode moves in a direction perpendicular to the surface of the thin semiconductor layer when a dynamic force is imposed on the second movable electrode while a second carrier voltage is being applied thereto, a second capacitance being formed between the second movable electrode and the base substrate, wherein;
the first capacitance varies according to the dynamic force applied to the first movable electrode, and the second capacitance varies, in a manner different from the first capacitance, according to the dynamic force applied to the second movable electrode; and
an output signal representing a capacitance difference between the first capacitance and the second capacitance is taken out from the base substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A semiconductor dynamic sensor formed on a laminated substrate composed of a base substrate, an insulation layer and a thin semiconductor layer, laminated in this order, the semiconductor dynamic sensor comprising:
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a first capacitor including a first beam structure formed on the thin semiconductor layer, the first beam structure having first beams and a first movable electrode supported by the first beams and facing the base substrate with an air gap therebetween, so that the first movable electrode moves in a direction perpendicular to the surface of the thin semiconductor layer when a dynamic force is imposed on the first movable electrode while a first carrier voltage is being applied thereto, a first capacitance being formed between the first movable electrode and the base substrate; and
a third capacitor having an output electrode formed on the thin semiconductor layer, the output electrode being solidly connected to the base substrate via the insulation layer, thereby forming a third capacitance between the output electrode and the base substrate, wherein;
an output signal representing the first capacitance that varies in accordance with the dynamic force imposed on the first movable electrode is transmitted from the base substrate to the output electrode through the third capacitance and is taken out from the output electrode. - View Dependent Claims (11, 12, 13)
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Specification