SAW Magnetic Sensor Simplified Film Stack Design
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Solution Overview
Problem
Traditional SAW magnetic sensors have complex film layer structures, leading to uncontrollable factors and complicated preparation processes, which hinder their efficiency and reliability.
Innovation Solution
A simplified SAW magnetic sensor design featuring a silicon or silicon dioxide substrate with a seed layer, a highly oriented piezoelectric thin film, and a magnetic interdigital transducer, where the interdigital electrode is directly stacked on the piezoelectric thin film, utilizing the ΔE effect to detect external magnetic fields by measuring changes in resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional SAW magnetic sensor uses multiple film layer structures (piezoelectric thin film, magneto elastic thin film, ferromagnetic or anti-ferromagnetic layer), then the sensor can achieve magnetic detection functionality, but the device complexity and number of uncontrollable factors increase
Solution Approach 1:
The patent extracts and removes the magneto elastic thin film and ferromagnetic or anti-ferromagnetic layer from the traditional multi-layer structure, retaining only the essential piezoelectric thin film and interdigital transducer components. This simplification reduces the number of uncontrollable factors while preserving the core magnetic detection functionality through the piezoelectric material's inherent properties
Solution Approach 2:
The patent merges the functions of multiple separate layers into a more integrated structure where the piezoelectric thin film directly supports the interdigital transducer, eliminating the need for intermediate magneto elastic and ferromagnetic layers. This consolidation reduces device complexity while maintaining detection capability
2Reliability
If a traditional SAW magnetic sensor uses multiple film layer structures, then magnetic detection can be achieved, but the preparation process becomes complicated
Solution Approach 1:
The patent removes the complex sequence of depositing magneto elastic thin films and ferromagnetic or anti-ferromagnetic layers, retaining only the essential piezoelectric thin film deposition and interdigital transducer fabrication steps. This extraction significantly simplifies the manufacturing process while preserving magnetic detection capability
Solution Approach 2:
The patent segments the device into distinct functional modules: the piezoelectric thin film layer, the interdigital transducer, and the substrate, with clear interfaces between components. This segmentation allows for more straightforward manufacturing and quality control compared to the traditional multi-layer approach
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 sensor achieves high sensitivity, high definition, and ease of miniaturization with a simplified process, compatible with microelectronics, while reducing technical complexity and costs.
Implementation Method 1
a piezoelectric thin film (30), and a interdigital transducer (40) stacked from bottom to top
Implementation Method 2
utilizing the ΔE effect to detect external magnetic fields by changes in resonance frequency
Data Source
AI summary
A SAW (Surface Acoustic Wave) magnetic sensor includes: a piezoelectric thin film; a seed layer; an interdigital transducer arranged respectively on each side of the piezoelectric thin film, the interdigital transducer comprising an interdigital electrode made from magnetic materials, and reflector grids located at both ends of the interdigital electrode; an underlying substrate arranged at the seed layer opposite to the piezoelectric thin film. A manufacturing method for the sensor is also disclosed.