Serpentine NEMS Membrane Cancels Self-Generated Magnetic Fields
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Solution Overview
Problem
Existing membrane-based nano-electromechanical systems (NEMS) devices face challenges in sensitivity and self-generated magnetic field interference, particularly when measuring magnetic fields operating below 10 kHz.
Innovation Solution
The implementation of a serpentine shape arrangement for the electrically conductive membrane, combined with the 'wicking down' of graphene on the edge of oxide cavities, enhances sensitivity and cancels self-generated magnetic fields by providing equal oppositely directed currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional membrane arrangement is used, then the device structure is simple, but the sensitivity is insufficient and self-generated magnetic field interference is significant
Solution Approach 1:
The membrane is divided into multiple segments arranged in a serpentine pattern, with each segment carrying current in alternating directions. This segmentation allows the magnetic fields generated by adjacent segments to cancel each other out while maintaining high sensitivity to external magnetic fields.
Solution Approach 2:
The serpentine arrangement creates an asymmetric current distribution pattern where adjacent membrane segments have oppositely directed currents. This asymmetric configuration is key to canceling self-generated magnetic fields while preserving sensitivity to external fields.
2Measurement precision
If the membrane is made thinner to increase sensitivity, then the measurement precision improves, but the mechanical strength decreases
Solution Approach 1:
The device uses a composite structure combining an ultra-thin graphene membrane (for high sensitivity and electrical conductivity) with a silicon nitride membrane (for mechanical strength and structural support). This composite approach allows the thin membrane to maintain both high sensitivity and adequate mechanical strength.
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
This configuration results in improved magnetic flux density sensing capabilities, including three-axis sensing, with increased sensitivity and reduced interference from self-generated fields, making it suitable for applications like brain-computer interfaces.
Implementation Method 1
current is operable to flow through the thin, electrically conductive membrane between the first connector and the second connector causing the thin, electrically conductive membrane facing the cavity to deflect in a direction perpendicular to the first plane in the presence of a magnetic field
Data Source
AI summary
Nano-electromechanical systems (NEMS) sensor devices that utilize thin electrically conductive membranes, which can be, for example, graphene membranes. The NEMS devices can have a trough shape (such as a serpentine shape arrangement) of the electrically conductive membrane. The thin, electrically conductive membrane has membrane-structures disposed upon it in an array of cavities. These membrane structures are between the thin, electrically conductive membrane and the main membrane trace. Such an arrangement increases the sensitivity of the NEMS sensor device. The electrically conductive membrane can be controllably wicked down on the edge of the oxide cavity to increase the sensitivity of the NEMS sensor device. Such NEMS sensor devices include NEMS sensor devices that are well suited to applications that measure magnetic fields that, operate below 10 kHz, such as brain-computer interfaces.