Capacitive MEMS device with programmable offset voltage control
First Claim
1. A device comprising:
- an electrode;
a movable layer extending over the electrode and forming a cavity therebetween; and
a material coupled to one or both the electrode and the movable layer, the material comprising a dielectric layer with introduced charge trapping sites;
wherein the movable layer is configured to move in response to an electrical potential between the electrode and at least a portion of the movable layer, the electrical potential being greater than an actuation threshold voltage, and wherein charge is transferred to or from the material to configurably change the actuation threshold voltage to a target level in response to actuation of the device.
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Accused Products
Abstract
A capacitive MEMS device is formed having a material between electrodes that traps and retains charges. The material can be realized in several configurations. It can be a multilayer dielectric stack with regions of different band gap energies or band energy levels. The dielectric materials can be trappy itself, i.e. when defects or trap sites are pre-fabricated in the material. Another configuration involves a thin layer of a conductive material with the energy level in the forbidden gap of the dielectric layer. The device may be programmed (i.e. offset and threshold voltages pre-set) by a method making advantageous use of charge storage in the material, wherein the interferometric modulator is pre-charged in such a way that the hysteresis curve shifts, and the actuation voltage threshold of the modulator is significantly lowered. During programming phase, charge transfer between the electrodes and the materials can be performed by applying voltage to the electrodes (i.e. applying electrical field across the material) or by UV-illumination and injection of electrical charges over the energy barrier. The interferometric modulator may then be retained in an actuated state with a significantly lower actuation voltage, thereby saving power.
32 Citations
68 Claims
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1. A device comprising:
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an electrode; a movable layer extending over the electrode and forming a cavity therebetween; and a material coupled to one or both the electrode and the movable layer, the material comprising a dielectric layer with introduced charge trapping sites; wherein the movable layer is configured to move in response to an electrical potential between the electrode and at least a portion of the movable layer, the electrical potential being greater than an actuation threshold voltage, and wherein charge is transferred to or from the material to configurably change the actuation threshold voltage to a target level in response to actuation of the device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A device comprising:
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an electrode; a multi-layer material comprising a first material and at least one other material with an electron energy band gap that is less than the electron energy band gap of the first material; and a movable layer extending over the surface of the multi-layer material so as to form a cavity therebetween, the movable layer being configured to contact the multi-layer material in response to an electrical potential between the electrode and at least a portion of the movable layer that is greater than an actuation threshold voltage, wherein when the movable layer contacts the multi-layer material, charge is transferred between the movable layer and the multi-layer material to configurably change the actuation threshold voltage to a target level. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A device comprising:
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means for altering a state of the device, the state being based on an actuation threshold voltage; and means for trapping charge in a portion of the device so as to configurably change the actuation threshold voltage to a target level in response to actuation of the device, where the charge trapping means comprises a multi-layer material comprising a first material and at least one other material, the at least one other material either having an electron energy band gap that is less than the electron energy band gap of the first material or having an energy level below the conduction band of the first material. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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61. A device comprising:
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an electrode; a multi-layer material comprising a first insulating layer, a second insulating layer, and a charge trapping material located between the first and second insulating layer, the charge trapping material forming a potential well for charge carriers; and a movable layer extending over the surface of the multi-layer material so as to form a cavity therebetween, the movable layer being configured to contact the multi-layer material in response to an electrical potential between the electrode and at least a portion of the movable layer that is greater than an actuation threshold voltage, wherein when the movable layer contacts the multi-layer material, charge is transferred between the movable layer and the multi-layer material to configurably change the actuation threshold voltage to a target level. - View Dependent Claims (62, 63, 64, 65, 66, 67)
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68. A device comprising:
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an electrode; a multi-layer material comprising a first material and at least one other material with an energy level below the conduction band of the first material; and a movable layer extending over the surface of the multi-layer material so as to form a cavity therebetween, the movable layer being configured to contact the multi-layer material in response to an electrical potential between the electrode and at least a portion of the movable layer that is greater than an actuation threshold voltage, wherein when the movable layer contacts the multi-layer material, charge is transferred between the movable layer and the multi-layer material to configurably change the actuation threshold voltage to a target level.
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Specification