GMR-TMR Magnetoresistance Assembly for Wide-Range Field Sensing
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Solution Overview
Problem
Conventional methods face challenges in depositing GMR and TMR elements on the same substrate due to their different layer structures, making it difficult to fabricate magnetoresistance sensors with optimal sensitivity and noise characteristics.
Innovation Solution
The development of a magnetoresistance assembly where GMR and TMR elements are deposited over the same substrate, allowing for simultaneous electrical activation and response to magnetic fields, with TMR elements providing higher sensitivity for smaller fields and GMR elements for higher fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If GMR and TMR elements are deposited on the same substrate, then fabrication is simplified and manufacturing cost is reduced, but the different layer structures make deposition difficult
Solution Approach 1:
The magnetoresistance assembly is segmented into distinct GMR and TMR elements with separate layer structures deposited on the same substrate. The GMR element comprises a first stack of magnetic and nonmagnetic layers, while the TMR element comprises a second stack with different layer compositions. This segmentation allows each element to be optimized for its specific function while being fabricated using sequential deposition processes on a common substrate, resolving the contradiction between fabrication simplicity and layer structure complexity.
Solution Approach 2:
Different regions of the substrate are assigned different local qualities through selective deposition of GMR and TMR layer stacks. The GMR element region uses a first set of magnetic layers (e.g., CoFeB) and nonmagnetic layers (e.g., Ru, Ta), while the TMR element region uses a second set with different compositions (e.g., CoFeB/MgO/CoFeB). This local differentiation enables both element types to coexist on the same substrate with their respective optimized properties, balancing fabrication ease with structural complexity.
2Measurement precision
If TMR elements are used for higher sensitivity, then sensitivity to small magnetic fields is improved, but noise at low frequencies increases
Solution Approach 1:
The patent merges GMR and TMR elements into a single magnetoresistance assembly on the same substrate, allowing them to operate in conjunction. The TMR element provides high sensitivity for detecting small magnetic fields, while the GMR element contributes to the overall sensing capability with lower noise characteristics. By combining both element types, the system achieves enhanced sensitivity to small fields while mitigating the noise problem through the complementary properties of the GMR element.
Solution Approach 2:
The magnetoresistance assembly uses composite material structures where GMR and TMR elements are integrated on the same substrate. The GMR element employs a composite stack of ferromagnetic layers (CoFeB) separated by nonmagnetic spacer layers (Ru, Ta), while the TMR element uses a composite structure with magnetization tunnel junction layers (CoFeB/MgO/CoFeB). This composite approach allows the system to leverage the high sensitivity of TMR materials while the GMR component provides noise suppression, resolving the contradiction between sensitivity and noise.
3Adaptability or versatility
If GMR elements are used for higher field sensing, then operating range at high fields is improved, but sensitivity to small fields is reduced
Solution Approach 1:
The magnetoresistance assembly is designed to dynamically utilize both GMR and TMR elements based on the strength of the applied magnetic field. For small magnetic fields, the TMR element provides high sensitivity response, while for larger magnetic fields, the GMR element contributes to extended operating range. This dynamic operation mode allows the system to adapt to different field strengths, resolving the contradiction between operating range and sensitivity by having each element specialize in different field regimes.
Solution Approach 2:
The magnetoresistance assembly achieves universality by integrating both GMR and TMR elements that can detect across different magnetic field ranges. The GMR element provides multi-functionality for high-field sensing while the TMR element provides high sensitivity for low-field detection. Together, they create a universal sensing system that can accurately measure magnetic fields across a broad dynamic range, from small to large field strengths, resolving the trade-off between operating range and sensitivity.
4Ease of manufacture
If separate substrates are used for GMR and TMR elements, then each element can be fabricated independently, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the fabrication of GMR and TMR elements by depositing both element stacks on the same substrate using sequential deposition processes. The GMR element stack and TMR element stack are formed in different regions of the same substrate, allowing both elements to be fabricated independently in terms of their layer structures while being integrated into a single device architecture. This approach reduces device complexity by eliminating the need for separate substrates and interconnection structures, while maintaining the independence of each element's fabrication process.
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 approach simplifies fabrication, enhances sensitivity, and extends the operating range of magnetic field sensors by leveraging the complementary strengths of GMR and TMR elements, while reducing manufacturing complexity and cost.
Implementation Method 1
The magnetoresistance element has a resistance that changes in relation to a magnetic field experienced by the magnetoresistance element
Implementation Method 2
The GMR and the TMR elements operate with spin electronics (i.e., electron spins) where the resistance is related to the magnetic orientation of different magnetic layers separated by nonmagnetic layers
Implementation Method 3
a tunneling magnetoresistance (TMR) element, also called a magnetic tunnel junction (MTJ) element
Implementation Method 4
a giant magnetoresistance (GMR) element
Data Source
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AI summary
A magnetoresistance assembly can include a substrate and a first GMR element disposed over the substrate, the first GMR element having a bottom surface and top surface. The magnetoresistance assembly can further include a first TMR element disposed over the substrate, the first TMR element having a top surface and a bottom surface, wherein a line perpendicular to and intersecting the top or bottom surface of the first TMR element intersects the first GMR element. The first GMR element and the first TMR element are in electrical communication.