MEMS Switch Electrode Segmentation for Low Contact Resistance
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Solution Overview
Problem
Conventional RF-MEMS switches face issues with high contact resistance due to oxide films and surface pollution, leading to increased driving voltage requirements and reliability concerns, particularly due to stiction phenomena, which complicates the formation of reliable electrical contacts.
Innovation Solution
A MEMS switch design where the electrostatic force is generated between a movable electrode and a counter electrode, divided into separate electrodes, allowing for independent voltage application with a time difference to achieve mechanical cleaning and stabilize contact formation, thereby reducing contact resistance and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrostatic force is used to contact the movable electrode with the signal electrode, then the switch can be operated, but high contact resistance occurs due to oxide films and surface pollution
Solution Approach 1:
The counter electrode is divided into two separate electrodes (first counter electrode and second counter electrode) positioned at different locations relative to the movable electrode. This segmentation allows independent voltage application to each counter electrode, enabling sequential actuation that generates mechanical cleaning effect during contact formation, thereby reducing contact resistance while maintaining reliable electrical contact.
2Manufacturing precision
If driving voltage is increased to reduce contact resistance, then mechanical cleaning effect improves, but power consumption increases
Solution Approach 1:
The voltage is applied sequentially to the first counter electrode and then to the second counter electrode with a time difference, creating a periodic actuation pattern. This sequential periodic action generates mechanical cleaning effect through relative motion during contact formation, achieving low contact resistance while using lower overall power compared to simultaneous high-voltage application.
3Manufacturing precision
If high driving voltage is applied to achieve mechanical cleaning, then contact resistance decreases, but stiction phenomenon increases
Solution Approach 1:
The sequential periodic voltage application creates controlled mechanical cleaning effect during contact formation without sustaining high voltage continuously. The time-difference application allows the movable electrode to be actuated by one counter electrode then the other, generating cleaning motion while avoiding continuous high-voltage contact that causes stiction, thus maintaining both low contact resistance and reliable separation.
4Manufacturing precision
If the counter electrode is divided into separate electrodes with time-difference voltage application, then mechanical cleaning effect is achieved, but device complexity increases
Solution Approach 1:
The counter electrode is segmented into two separate electrodes positioned at different locations, allowing independent voltage control. This segmentation enables the generation of mechanical cleaning effect through sequential actuation while maintaining a relatively simple overall structure that can be integrated into existing MEMS switch architectures, balancing complexity with performance benefits.
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 solution enables the formation of highly reliable contacts with low contact resistance and low insertion loss at reduced driving voltage, enhancing the reliability and power efficiency of the MEMS switch.
Implementation Method 1
an electrical contact can be made between the movable electrode and the signal electrode by electrostatic force generated between the movable electrode and the counter electrode
Implementation Method 2
The mechanical cleaning effect is obtained by physical force which is applied upon the formation of electrical contact
Data Source
AI summary
A MEMS switch is provided wherein contact force sufficient to make a contact having low contact resistance is maintained after contact-formation to maintain low contact resistance at the signal transmission contact in “on” state. Provided is a MEMS switch 100 including a first electrode 101, a second electrode 104 opposed to and separated from the first electrode, a third and a fourth electrodes 1021 and 1022, wherein electrical contact is made between the electrodes 101 and 104 by electrostatic force generated between the electrode 101 and the electrodes 1021, 1022, and a bump which can form the contact between the electrode 101 and the electrode 1021 and/or 1022 is provided on the electrode 101, and a gap is formed between the electrode 101 and the electrode 1021 and/or 1022 when the electrical contact is made, and control signals are input to the electrodes 1021 and 1022 independently.