Liquid Dielectric MEMS Switch for Low Voltage Actuation
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Solution Overview
Problem
MEMS switches face limitations such as high pull-in voltages and slow response times, which restrict their application, and they suffer from significant leakage when using low voltage, making them unsuitable for various environments like space and mining due to reliability issues at extreme conditions.
Innovation Solution
A microelectromechanical system (MEMS) switch utilizing a liquid dielectric, which increases capacitance and reduces pull-in voltage by using liquids with high permittivity, such as water, gasoline, or ethanol, to act as a flexible dielectric, thereby reducing actuation voltage and addressing issues like stiction and damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional solid dielectric materials are used to increase capacitance, then the permittivity increases, but the moving part cannot be actuated because the rigid dielectric blocks movement
Solution Approach 1:
The patent uses a liquid dielectric material instead of a solid dielectric. The liquid fills the gap between the fixed electrode and the movable part, providing high permittivity to increase capacitance and electrostatic force. The liquid's fluidity allows it to accommodate the movement of the movable part during actuation, resolving the contradiction between increasing permittivity and maintaining actuation capability.
2Force
If the gap separation between parallel plates is reduced to increase capacitance, then the electrostatic force increases, but the pull-in voltage becomes excessively high
Solution Approach 1:
The patent changes the dielectric parameter by using a liquid dielectric with high permittivity. This allows the system to maintain a practical gap separation while achieving the necessary electrostatic force. The high permittivity of the liquid dielectric compensates for the gap distance, enabling adequate electrostatic force at reasonable pull-in voltages.
3Force
If the area of parallel plates is increased to increase capacitance, then the electrostatic force increases, but the device density and yield decrease
Solution Approach 1:
The patent changes the dielectric parameter by introducing a liquid dielectric with high permittivity between the parallel plates. This allows the system to achieve the required capacitance and electrostatic force with smaller plate areas, thereby maintaining high device density and yield while providing sufficient actuation force.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The liquid dielectric MEMS switch achieves a significant reduction in pull-in voltage, from as high as 44V to as low as 5.36V, and satisfies XOR logic operations, enabling smaller, lower power consumption devices suitable for harsh environments.
Implementation Method 1
the liquid dielectric fills at least a portion of a volume between the cantilevered source and the first actuation gate
Implementation Method 2
using liquids with high permittivity, such as water, gasoline, or ethanol, to act as a flexible dielectric, thereby reducing actuation voltage
Implementation Method 3
The net force applied to the parallel plate is the difference between the electrostatic force and the structural damping force
Implementation Method 4
addressing issues like stiction and damping
Data Source
AI summary
A microelectromechanical system (MEMS) switch with liquid dielectric and a method of fabrication thereof are provided. In the context of the MEMS switch, a MEMS switch is provided including a cantilevered source switch, a first actuation gate disposed parallel to the cantilevered source switch, a first drain disposed parallel to a movable end of the cantilevered source switch, and a liquid dielectric disposed within a housing of the microelectromechanical system switch.