Electrostatically controlled variable capacitor
First Claim
1. A MEMS (Micro Electro Mechanical System) device driven by electrostatic forces, comprising:
- a microelectronic substrate defining a generally planar surface;
a substrate signal electrode forming a layer on said substrate;
a substrate control electrode forming a layer on said substrate and electrically isolated from said substrate signal electrode;
a moveable composite overlying said substrate signal electrode and said substrate control electrode and having a signal electrode, a control electrode and a biasing element, said composite having a fixed portion attached to the underlying substrate, a medial portion adjacent to the fixed portion and a distal portion adjacent to the medial portion, the medial and distal portion being moveable with respect to said substrate signal electrode; and
an insulator electrically isolating said substrate signal electrode from said composite signal electrode and said substrate control electrode from said composite control electrode, whereby the capacitance between said substrate signal electrode and said composite signal electrode is varied by changing the separation between said substrate and said composite.
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Accused Products
Abstract
A MEMS (Micro Electro Mechanical System) electrostatically operated high voltage variable controlled capacitor device is provided. This device can store high energy over a wide range while using relatively low electrostatic operating voltages. The MEMS device comprises a microelectronic substrate, a substrate signal electrode, and one or more substrate control electrodes. The MEMS device also includes a moveable composite overlying the substrate, having a composite signal electrode, one or more composite control electrodes, and a biasing element. In cross-section, the moveable composite comprises at least one electrode layer and, in most instances, a biasing layer. In length, the moveable composite comprises a fixed portion attached to the underlying substrate and a distal portion moveable with respect to the substrate electrode. The distal and/or medial portions of the moveable composite are biased in position when no electrostatic force is applied. Additionally, the MEMS device comprises insulators to electrically isolate the substrate and electrodes. Applying a variable controlled voltage between the substrate control electrode and moveable composite control electrode, controls the bias of the moveable composite and, in turn, controls the capacitance between the substrate signal electrode and the composite signal electrode. Various embodiments further define the various layering alternatives if the moveable composite, shaping of the electrodes and placement of the electrodes. Additionally, a system for electrostatically controlled variable capacitance comprises a variable controlled voltage source coupled to the control electrodes of the MEMS device of the present invention and a circuit signal electrically coupled to the signal electrodes of the MEMS device. A method of using and a method for making the aforementioned electrostatic MEMS device are also provided.
210 Citations
57 Claims
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1. A MEMS (Micro Electro Mechanical System) device driven by electrostatic forces, comprising:
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a microelectronic substrate defining a generally planar surface;
a substrate signal electrode forming a layer on said substrate;
a substrate control electrode forming a layer on said substrate and electrically isolated from said substrate signal electrode;
a moveable composite overlying said substrate signal electrode and said substrate control electrode and having a signal electrode, a control electrode and a biasing element, said composite having a fixed portion attached to the underlying substrate, a medial portion adjacent to the fixed portion and a distal portion adjacent to the medial portion, the medial and distal portion being moveable with respect to said substrate signal electrode; and
an insulator electrically isolating said substrate signal electrode from said composite signal electrode and said substrate control electrode from said composite control electrode, whereby the capacitance between said substrate signal electrode and said composite signal electrode is varied by changing the separation between said substrate and said composite. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A MEMS device driven by electrostatic forces, comprising:
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a microelectronic substrate defining a generally planar surface;
a substrate signal electrode forming a layer on said substrate;
a substrate control electrode forming a layer on said substrate and electrically isolated from said substrate signal electrode;
a moveable composite overlying said substrate signal electrode and said substrate control electrode and having a signal electrode, a control electrode and a biasing element, said moveable composite having a fixed portion attached to the underlying substrate, a medial portion defining an air gap between said substrate signal electrode and said composite signal electrode and a distal portion moveable with respect to said substrate signal electrode; and
an insulator electrically isolating said substrate signal electrode from said composite signal electrode and said substrate control electrode from said pair of composite control electrodes, whereby the capacitance between said substrate signal electrode and said moveable composite signal electrode is varied by changing the separation between said substrate and said composite. - View Dependent Claims (43, 44, 45, 46, 47, 48)
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49. A MEMS device driven by electrostatic forces, comprising:
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a microelectronic substrate defining a generally planar surface;
at least one substrate signal electrode forming a layer on said substrate;
at least one substrate control electrode forming a layer on said substrate and electrically isolated from said substrate signal electrode;
a moveable composite overlying said at least one substrate signal electrode and said at least one substrate control electrode and having at least one signal electrode, at least one control electrode and a biasing element, said composite having a fixed portion attached to the underlying substrate, a medial portion adjacent to the fixed portion and a distal portion adjacent to the medial portion, the medial and distal portion being moveable with respect to said at least one substrate signal electrode; and
an insulator electrically isolating said at least one substrate signal electrode from said at least one composite signal electrode and said at least one substrate control electrode from said at least one composite control electrode, whereby the capacitance between said at least one substrate signal electrode and said at least one composite signal electrode is varied by changing the separation between said substrate and said composite. - View Dependent Claims (50, 51)
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52. A system for electrostatically controlling variable capacitance, the system comprising:
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a variable controlled voltage source;
a MEMS device having a microelectronic substrate comprising a substrate signal electrode layer and an electrically isolated substrate control electrode layer, and an electrically isolated moveable composite having a signal electrode, a control electrode and biasing element, the substrate control electrode and the composite control electrode electrically coupled to said variable controlled voltage source, whereby the movable composite biasing is controlled in response to voltage supplied to the substrate control electrode and the moveable composite control electrode; and
an electrical signal circuit electrically coupled to the substrate signal electrode and the composite signal electrode wherein the capacitance therebetween is variable in response to variations in said voltage source.
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53. A method of using a MEMS device having a microelectronic substrate having a substrate signal electrode and a substrate control electrode, and a moveable composite having a signal electrode, a control electrode and biasing element, the composite movable in response to an electrostatic force created between the substrate control electrode and the moveable composite control electrode, the method comprising the steps of:
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selectively generating a variable electrostatic force between the substrate control electrode and the moveable composite control electrode; and
moving the moveable composite with respect to the substrate in response to the variable electrostatic force to vary the capacitance between the substrate signal electrode and composite signal electrode. - View Dependent Claims (54, 55, 56, 57)
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Specification