Vertical Hall Effect Sensor Current Focus CMOS
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Solution Overview
Problem
Existing CMOS Hall devices are limited to measuring magnetic fields perpendicular to the chip surface, and attempts to measure multiple dimensions using vertical Hall effect sensors result in low sensitivity, instability, and high manufacturing and post-processing costs.
Innovation Solution
A CMOS sensor system with a vertical Hall effect configuration that allows current to flow in the Z-direction, utilizing selective doping and buried n-doped wells to enhance current path divergence and sensitivity, enabling detection of magnetic fields parallel to the surface and perpendicular to the chip centerline, while also isolating the detection current from extraneous substrate currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If vertical Hall effect devices are used to measure multiple dimensions of magnetic field, then measurement capability in multiple dimensions is improved, but sensitivity deteriorates and cross-talk between dimensions increases
Solution Approach 1:
The sensor is divided into multiple independent sensing elements arranged in a specific geometry (e.g., perpendicular Hall effect plates). Each element measures a specific dimension of the magnetic field independently, allowing multi-dimensional measurement while maintaining high sensitivity for each individual measurement channel and minimizing cross-talk through proper spatial arrangement and isolation structures.
Solution Approach 2:
The patent transitions from planar current flow to vertical current flow through the substrate thickness, utilizing the third dimension (Z-axis) for current transport. This vertical configuration enables the Hall effect plates to be stacked or arranged in three-dimensional space, allowing simultaneous measurement of magnetic field components in multiple dimensions while maintaining high sensitivity through optimized current paths and magnetic field interaction geometry.
2Adaptability or versatility
If vertical Hall effect devices are used, then measurement capability is improved, but stability deteriorates
Solution Approach 1:
Multiple Hall effect sensing elements are combined into a single integrated sensor structure that can simultaneously measure multiple magnetic field dimensions. The sensor integrates current sources, sensing elements, and signal processing circuitry into one unified device, improving stability through consistent manufacturing conditions and reduced variability between separate components while maintaining multi-dimensional measurement capability.
Solution Approach 2:
The sensor design uses symmetric or complementary arrangements of Hall effect plates that can measure different magnetic field dimensions using the same fundamental sensing mechanism. This universal approach ensures consistent performance across all measurement channels and improves overall stability by eliminating the need for different sensing technologies for different dimensions.
3Adaptability or versatility
If packaged sensors are used to measure multiple dimensions of magnetic field, then measurement capability is improved, but manufacturing cost increases
Solution Approach 1:
Multiple sensing elements and their associated current sources are integrated into a single monolithic sensor chip using standard CMOS fabrication processes. This integration eliminates the need for separate packaging of multiple chips, reducing manufacturing complexity and cost while maintaining the ability to measure multiple magnetic field dimensions simultaneously through the integrated multi-element structure.
Solution Approach 2:
The sensor design uses a unified fabrication process and common structural elements for all sensing channels, allowing mass production using standard semiconductor manufacturing techniques. This universal design approach enables cost-effective manufacturing of multi-dimensional magnetic field sensors without requiring specialized packaging or assembly processes for each sensing element.
4Measurement precision
If magnetic concentrators are used, then sensitivity is improved, but manufacturing cost and post-processing cost increase
Solution Approach 1:
The sensor integrates high-sensitivity sensing elements directly with on-chip current sources and signal processing circuitry in a single CMOS-fabricated device. This integration achieves high sensitivity through optimized Hall effect plate geometry and current distribution while eliminating the need for separate magnetic concentrator components and their associated manufacturing and post-processing steps.
Solution Approach 2:
The sensor achieves high sensitivity by optimizing parameters such as Hall effect plate geometry, doping concentrations, and current density distributions through standard CMOS fabrication process control. This approach attains high sensitivity through material and structural parameter optimization rather than through additional magnetic concentrator components, thereby reducing manufacturing complexity and cost.
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 effective measurement of magnetic field components in multiple dimensions with improved sensitivity and reduced cross-talk, while maintaining manufacturing simplicity and cost-effectiveness by using standard CMOS processes.
Implementation Method 1
Hall Effect sensors incorporate a Hall Effect plate, which is either an n- or p-doped area, supplied with bias current/voltage. In presence of a magnetic field the carriers that are moving in the doped area are deflected by the Lorentz force, and a Hall electrical field appears. The Hall voltage Vh appears across the positive and negative contacts of the Hall Effect plate.
Implementation Method 2
In presence of a magnetic field the carriers that are moving in the doped area are deflected by the Lorentz force, and a Hall electrical field appears.
Data Source
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AI summary
A complimentary metal oxide semiconductor (CMOS) sensor system (100) in one embodiment includes a doped substrate (102), a doped central island (108) extending downwardly within the doped substrate from an upper surface of the doped substrate, and a first doped outer island (106) extending downwardly within the doped substrate from the upper surface of the doped substrate, the first outer island electrically isolated from the central island within an upper portion of the substrate, and electrically coupled to the central island within a lower portion of the substrate.