Field-Effect Magnetic Sensor Inversion Layer Sensitivity
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Solution Overview
Problem
Magnetic sensors are relatively insensitive to small magnetic fields or variations, limiting their application in various industries, particularly in automotive and other fields where precise detection is required.
Innovation Solution
Field-effect magnetic sensors with specific terminal configurations and gate control mechanisms that create an inversion layer to enhance current flow in response to magnetic fields, allowing for differential current detection and improved sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic sensors are used, then the sensor can detect magnetic fields, but the sensitivity for detecting small magnetic fields or small variations in magnetic fields is relatively low
Solution Approach 1:
The sensor divides the current path into multiple channel regions separated by drift regions, creating distinct segments that can be independently controlled by gates. This segmentation allows for enhanced sensitivity by creating multiple inversion layers that amplify the magnetoresistive effect while maintaining reliable detection through the combined signal from all channels.
Solution Approach 2:
The patent introduces drift regions with specific doping characteristics between channel regions, and uses gates to create localized inversion layers only where needed. This local quality enhancement allows the sensor to optimize sensitivity in specific regions while maintaining overall device reliability through controlled current flow paths.
2Ease of manufacture
If field-effect transistors are used in conventional configurations, then the sensor can be fabricated in standard IC processes, but the sensitivity for detecting small magnetic field variations is limited
Solution Approach 1:
The patent merges multiple channel-drift-channel segments into a single integrated sensor structure that processes magnetic field information collectively. This merging maintains compatibility with standard IC fabrication processes while achieving enhanced sensitivity through the combined magnetoresistive effects of all segments, allowing detection of small magnetic field variations that would be imperceptible in single-channel configurations.
Solution Approach 2:
The invention extends the conventional planar FET structure by introducing vertical drift regions and multiple gate-controlled channels, effectively adding dimensional complexity to the fabrication process. This dimensional enhancement maintains compatibility with standard IC processes while significantly improving sensitivity to small magnetic field variations through the cumulative effect of multiple inversion layers.
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 detection of magnetic fields with increased sensitivity, allowing for more precise applications in automotive and other industries by differentiating current flow between terminals in the presence of a magnetic field.
Implementation Method 1
A gate (or separate gates) adjacent the channel regions biases the channel regions to cause the channel regions to permit current flow between the third source/drain terminal and each of the first and second source/drain terminals
Implementation Method 2
The sensor is responsive to a magnetic field to, when in a biased state, pass a greater amount of current between the third source/drain terminal and one of the first and second source/drain terminals, relative to an amount of current passed between the third source/drain terminal and the other one of the first and second source/drain terminals
Data Source
AI summary
A field-effect magnetic sensor facilitates highly-sensitive magnetic field detection. In accordance with one or more example embodiments, current flow respectively between first and second source/drain terminals and a third source/drain terminal is controlled using inversion layers in separate channel regions for each of the first and second terminals. In response to a magnetic field, a greater amount of current is passed between the third source/drain terminal and one of the first and second source/drain terminals, relative to an amount of current passed between the third source/drain terminal and the other one of the first and second source/drain terminals.