Magnetoresistance Sensor Height Adjustment for Noise Reduction
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Solution Overview
Problem
The magnetoresistance effect element in conventional biosensors has unstable magnetization at the outer periphery, leading to noise interference when magnetic beads are captured, which decreases the accuracy of biomolecule detection.
Innovation Solution
A magnetic sensor with a magnetoresistance effect element configured in a line shape on a substrate, featuring a height adjustment layer at the outer periphery to stabilize magnetization, and a protective layer with a higher height at the outer periphery region to minimize noise interference, allowing for accurate detection of biomolecules using magnetic beads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If magnetic beads are captured in the protective layer on the outer periphery of the magnetoresistance effect element, then the detection range is increased, but noise is superimposed on the output due to unstable magnetization, decreasing detection accuracy
Solution Approach 1:
The invention applies different heights of the protective layer to different regions of the magnetoresistance effect element. Specifically, the protective layer has a first height in a first region (outer periphery) and a second height in a second region (inner region), where the first height is greater than the second height. This local differentiation allows magnetic beads to be captured in the outer periphery region while preventing them from interfering with the unstable magnetization area, thus resolving the contradiction between expanding detection range and maintaining detection accuracy.
2Measurement precision
If the protective layer height is increased at the outer periphery, then noise interference from stray magnetic fields is reduced, but the device structure becomes more complex
Solution Approach 1:
The invention changes the height parameter of the protective layer to resolve the contradiction. By setting the protective layer height to be greater in the outer periphery region compared to the inner region, the structure effectively blocks stray magnetic fields from reaching the magnetoresistance effect element at the periphery, improving signal-to-noise ratio. This parameter modification achieves noise reduction without requiring additional complex components or structures.
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 high-accuracy detection of biomolecules by reducing noise interference from stray magnetic fields, enhancing the sensitivity and reliability of the biosensor.
Implementation Method 1
a magnetoresistance effect element, which is provided on the first surface of the substrate and in which the resistance of the magnetoresistance effect element changes in accordance with an input magnetic field
Data Source
AI summary
A magnetic sensor used to detect detection substances in samples includes a substrate having a first surface and a second surface, which is opposite to the first surface, a magnetoresistance effect element, which is provided on the first surface and in which the resistance of the magnetoresistance effect element changes in accordance with an input magnetic field, and a protective layer that covers the magnetoresistance effect element. The magnetoresistance effect element is configured in a line shape extending in a first direction on the first surface, and has a first region that is positioned at the outer periphery in a plan view, and a second region that is surrounded by the first region. The height of a top surface of the protective layer on the first region is greater than the height of a top surface of the protective layer on the second region.