Buried Magnetic Sensor Vertical Stacking for Sensitivity
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Solution Overview
Problem
Conventional magnetic sensors are limited in size reduction due to the placement of analog and digital circuitry in a horizontal direction relative to the magnetic field sensing device, leading to increased device size and reduced sensitivity.
Innovation Solution
A buried magnetic sensor is developed using a silicon on insulator (SOI) substrate with the magnetic field sensing device embedded within, and circuitry positioned on top, minimizing external influences and optimizing the sensor area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If analog and digital circuitry are positioned in a horizontal direction with respect to the magnetic field sensing device, then the device can be manufactured using conventional processes, but the size of the magnetic sensor increases and sensitivity decreases
Solution Approach 1:
The patent positions the analog and digital circuitry in a vertical direction above the magnetic field sensing device rather than in a horizontal direction, utilizing the third dimension (z-axis) to resolve the contradiction between ease of manufacture and measurement precision
Solution Approach 2:
The circuitry is positioned above the magnetic field sensing device in a stacked configuration, with the sensor embedded in the substrate and circuitry layers above it, creating a nested vertical structure that reduces lateral footprint while maintaining functionality
2Area of stationary object
If the size of the magnetic sensor is reduced, then the total size of the IC chip decreases, but the sensitivity of the device regarding the earth's magnetic field decreases
Solution Approach 1:
The patent uses vertical stacking to reduce the lateral area of the sensor while maintaining sensitivity through improved current flow control and minimized external influences on the sensing element
3Measurement precision
If circuitry is positioned above the magnetic field sensing device in a vertical direction, then the size of the magnetic sensor is reduced and sensitivity is enhanced, but the device complexity increases
Solution Approach 1:
The device is segmented into distinct functional layers: the magnetic field sensing device embedded in the substrate, the buried oxide layer for isolation, and the circuitry layers above, allowing independent optimization of each segment while reducing overall complexity
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 reduces the size of the magnetic sensor while enhancing sensitivity and noise reduction by controlling current flow and minimizing defects, allowing for more precise magnetic field detection.
Implementation Method 1
A magnetic field sensing device, or Hall device, is a device that identifies a direction and a magnitude of magnetic field by use of a Hall effect
Data Source
AI summary
A semiconductor device including a circuitry, a magnetic sensor, and a buried oxide. The circuitry is formed on a substrate. The magnetic sensor has a sensing area formed under the circuitry. The buried oxide is disposed between the circuitry and the magnetic sensor. The sensing area comprises an N-doped area and a P-doped area doped deeper than the N-doped area, and sensor contacts connect the sensing area with the circuitry through the buried oxide.