Vertical Hall Sensor Cross-Terminal Geometry
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Solution Overview
Problem
Hall effect sensors for two-dimensional magnetic field sensing face a tradeoff between sensitivity and cost, with existing solutions lacking in sensitivity while attempting to reduce resistance for lower power consumption.
Innovation Solution
A microelectronic device employing a vertical Hall sensor with a cross-shaped upper terminal and buried layer, where the cross-members have length-to-width ratios of 5 to 12, and Hall sense taps around the periphery, providing higher sensitivity-to-resistance ratios compared to other configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the resistance of the Hall cell is reduced to reduce power consumption, then power consumption decreases, but sensitivity deteriorates
Solution Approach 1:
The patent transitions from planar Hall effect sensors to a vertical Hall effect sensor configuration, utilizing the third dimension (vertical orientation) to achieve both low resistance and high sensitivity. The vertical Hall plate with cross-shaped upper terminal and buried layer configuration allows current to flow vertically while magnetic field detection occurs in the horizontal plane, enabling simultaneous optimization of power consumption and sensitivity that cannot be achieved in traditional two-dimensional configurations.
2Measurement precision
If sensitivity is increased, then measurement precision improves, but resistance increases leading to higher power consumption
Solution Approach 1:
The patent optimizes the geometric parameters of the vertical Hall plate, specifically the length-to-width ratios of the cross-shaped upper terminal (5:1 to 12:1), to achieve the desired balance between sensitivity and resistance. By carefully controlling these dimensional parameters, the sensor achieves high sensitivity without proportionally increasing resistance, thereby maintaining acceptable power consumption levels.
3Measurement precision
If a vertical Hall sensor configuration is used to improve sensitivity-to-resistance ratio, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into a single vertical Hall plate structure. The cross-shaped upper terminal serves both as the current input path and as part of the magnetic field sensing structure, while the buried layer provides both electrical contact and structural support. This merging of functions reduces the number of separate components needed compared to other three-dimensional configurations, thereby limiting the increase in device complexity while still achieving superior sensitivity-to-resistance ratios.
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 configuration achieves a balance of higher sensitivity and reduced resistance, enhancing the magnetic field measurement sensitivity while maintaining low power consumption, thus addressing the sensitivity and cost tradeoff in two-dimensional magnetic field sensing.
Implementation Method 1
Vertical hall-effect sensor for detecting two-dimensional in-plane magnetic fields
Data Source
AI summary
A microelectronic device includes a vertical Hall sensor for measuring magnetic fields in two dimensions. In one implementation, the disclosed microelectronic device involves a vertical Hall plate with a cross-shaped upper terminal and a lower terminal which includes a buried layer. The cross-shaped upper terminal has a length-to-width ratio of 5 to 12 where it contacts the vertical Hall plate. The length is measured from one end of one arm of the cross-shaped upper terminal to an opposite end of an opposite arm. The width is an average width of both arms. Hall sense taps are located outside of the cross-shaped upper terminal. Current returns connect to the buried layer.