Vertical Hall Effect Sensor CMOS Doped Well Structure
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Solution Overview
Problem
Current CMOS Hall Effect sensors are limited to measuring magnetic fields perpendicular to the chip surface, and existing solutions for multi-dimensional magnetic field measurement are either costly or suffer from low sensitivity and cross-talk issues.
Innovation Solution
A CMOS-based vertical Hall Effect sensor system with a doped well structure that includes multiple surface and buried doped contacts, allowing for the detection of magnetic fields in multiple dimensions by orienting sensors at 90 degrees to each other and utilizing a Hall voltage measuring device to amplify the signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard CMOS Hall devices are used, then the sensor can be manufactured using common semiconductor processes, but the sensor can only measure magnetic fields perpendicular to the chip surface
Solution Approach 1:
The patent extends the Hall sensing structure from a single-plane configuration to a three-dimensional architecture by adding a buried doped well beneath the surface well. This vertical extension enables the sensor to detect magnetic field components in multiple dimensions (x, y, and z directions) while maintaining compatibility with standard CMOS manufacturing processes, thus resolving the contradiction between ease of manufacture and measurement versatility
2Adaptability or versatility
If chips are packaged perpendicular to each other for multi-dimensional measurement, then multi-dimensional magnetic field measurement is achieved, but specialized technology and special alignment are required resulting in increased manufacturing costs
Solution Approach 1:
The patent merges multiple sensing capabilities into a single integrated chip structure by combining surface and buried doped wells in a vertical configuration. This integration eliminates the need for separate perpendicular chips and their associated specialized packaging and alignment requirements, thereby achieving multi-dimensional measurement while reducing manufacturing complexity and cost
3Adaptability or versatility
If vertical Hall effect devices with Z-direction current flow are used, then out of plane magnetic field sensing is achieved, but the devices exhibit low sensitivity, instability, and excessive cross-talk
Solution Approach 1:
The patent segments the current path and sensing regions by creating distinct surface and buried doped wells separated by undoped regions. This segmentation isolates the vertical current flow paths, reducing cross-talk between different sensing dimensions while maintaining out-of-plane sensitivity. The separated structures also improve stability by preventing carrier mixing between layers
4Adaptability or versatility
If a single chip with magnetic concentrators is used, then out of plane sensor capability is achieved, but post processing costs increase
Solution Approach 1:
The patent employs doped semiconductor wells that inherently generate and concentrate the necessary magnetic field interactions through their electrical properties. The doped regions themselves serve as both the sensing element and the field concentration mechanism, eliminating the need for separate magnetic concentrator components and reducing post-processing assembly costs
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
Enables efficient and cost-effective measurement of magnetic fields in multiple dimensions, reducing manufacturing and post-processing costs while improving sensitivity and minimizing cross-talk.
Implementation Method 1
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
Implementation Method 2
Hall Effect sensors are among the most widely used magnetic sensors. Hall Effect sensors incorporate a Hall Effect plate
Data Source
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AI summary
A complimentary metal oxide semiconductor (CMOS) sensor system (100) in one embodiment includes a doped well (104) extending along a first axis of a doped substrate (102), a first electrical contact (106) positioned within the doped well, a second electrical contact (108) positioned within the doped well and spaced apart from the first electrical contact along the first axis, a third electrical contact (110) positioned within the doped well and located between the first electrical contact and the second electrical contact along the first axis, and a fourth electrical contact (122, 124) electrically coupled to the doped well at a location of the doped well below the third electrical contact.