Vertical Hall Sensor On-Chip Current Sensing
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Solution Overview
Problem
Conventional Hall sensors used for current sensing applications suffer from reduced sensitivity due to the long distance between the sensor and the current carrying conductor, leading to a weaker magnetic field and lower accuracy.
Innovation Solution
The implementation of a vertical Hall sensor positioned directly under a current carrying conductor in a first wiring layer, reducing the distance between the sensor and the conductor to enhance sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a planar Hall sensor is used with a current carrying conductor, then the sensor can detect current indirectly through the magnetic field, but the distance between the sensor and conductor is large resulting in lower sensitivity
Solution Approach 1:
The patent transitions from a planar Hall sensor configuration to a vertical Hall sensor configuration, changing the spatial dimension of sensor placement. The vertical Hall sensor is positioned directly beneath the current carrying conductor in the same wiring layer, reducing the distance from micrometers to nanometers and achieving significantly higher sensitivity.
2Ease of manufacture
If the Hall sensor is placed with an offset from the current carrying conductor, then the sensor structure is simplified, but the distance increases resulting in weaker magnetic field and lower sensitivity
Solution Approach 1:
The patent resolves this contradiction by moving the sensor placement from a planar offset configuration to a vertical configuration directly beneath the conductor. This dimensional change allows the sensor to be positioned as close as possible to the current path without requiring lateral offset, simultaneously achieving ease of manufacture and maximum magnetic field strength.
3Measurement precision
If a vertical Hall sensor is positioned directly under the current carrying conductor, then the distance is reduced enhancing sensitivity, but the sensor and conductor must be precisely aligned
Solution Approach 1:
The vertical configuration concentrates the alignment requirement to a single vertical position beneath the conductor, rather than requiring lateral positioning accuracy. This dimensional simplification makes precise alignment more achievable through standard semiconductor fabrication processes.
Solution Approach 2:
The patent integrates the vertical Hall sensor and current carrying conductor into the same wiring layer, merging their positions in the vertical dimension. This integration ensures automatic alignment through the fabrication process, reducing the need for separate alignment steps and improving manufacturing precision.
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 configuration achieves higher and more accurate sensitivity, with a magnetic field and Hall voltage increased by at least two orders of magnitude compared to conventional planar Hall sensor systems, allowing for precise current sensing.
Implementation Method 1
A Hall sensor is a type of sensor which detects the presence and magnitude of a magnetic field using the Hall effect. For example, the output voltage of a Hall sensor is directly proportional to the strength of the field.
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to an on-chip current sensor. The on-chip current sensor includes: a vertical Hall sensor; and a current carrying conductor in a first wiring layer above the vertical Hall sensor.