Hall Sensor Dielectric Isolation Current Displacement
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Solution Overview
Problem
Hall sensors in microelectronic devices face challenges in achieving high magnetic gain, low offset, and low noise levels while operating at low bias current without degrading long-term reliability or increasing fabrication costs.
Innovation Solution
The design includes a Hall sensor with a contact region in semiconductor material, an isolation structure of dielectric material on opposite sides, and a conductive spacer separated by an insulating layer, which enhances magnetic gain and reduces noise by displacing current deeper into the substrate and minimizing charge trapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the bias current is reduced to maintain low power consumption and avoid heating the Hall plate, then power consumption and heat generation are reduced, but the signal output and sensitivity of the Hall sensor deteriorate
Solution Approach 1:
The patent changes the physical parameters of the semiconductor substrate by creating a dopant concentration gradient, with a first dopant concentration in the Hall plate region and a second, higher dopant concentration in a deeper region. This parameter change allows the Hall sensor to achieve higher sensitivity at lower bias currents by optimizing the charge carrier density distribution throughout the substrate depth.
Solution Approach 2:
The patent extends the solution into the depth dimension of the substrate by creating a vertically stratified dopant concentration profile. Instead of only lateral variations, the dopant concentration varies with depth, allowing the Hall plate to interact with charge carriers from multiple depth levels, thereby enhancing sensitivity without increasing bias current.
2Measurement precision
If the Hall plate area is increased to improve sensitivity and signal output, then measurement precision is improved, but the device area and fabrication complexity increase
Solution Approach 1:
The patent changes the dopant concentration parameter vertically through the substrate depth rather than increasing the lateral area. By creating a region with higher dopant concentration at deeper levels, the Hall sensor achieves enhanced signal output through increased charge carrier availability without expanding the Hall plate's footprint on the surface.
Solution Approach 2:
The patent embeds a region of higher dopant concentration within the deeper portion of the substrate beneath the Hall plate. This nested structure allows the Hall plate to utilize charge carriers from both the surface region and the deeper, more heavily doped region, effectively increasing the active sensing volume without increasing the lateral device area.
3Area of stationary object
If isolation structures are placed closer to the contact region to reduce device area, then device area is reduced, but charge trapping in the dielectric material increases noise level
Solution Approach 1:
The patent resolves the contradiction by utilizing the depth dimension to separate the contact region from the isolation structure. Instead of only lateral separation, the contact region is positioned at a deeper level in the substrate, below the isolation structure. This vertical separation allows the Hall sensor to achieve compact lateral dimensions while maintaining sufficient distance from charge-trapping dielectric materials, thereby reducing noise.
Solution Approach 2:
The patent inverts the conventional arrangement by placing the contact region beneath the isolation structure rather than beside it. This inverted geometry allows the isolation structure to be positioned laterally closer to the Hall plate while the contact region, being deeper, remains electrically isolated from charge-trapping effects of the dielectric material.
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 improves the sensitivity and noise performance of the Hall sensor, maintaining low bias current and fabrication costs, thereby enhancing the device's reliability and accuracy.
Implementation Method 1
Hall sensors may be integrated into microelectronic devices to measure magnetic fields. A Hall sensor in a microelectronic device desirably has a high magnetic gain
Implementation Method 2
an isolation structure including dielectric material contacting the semiconductor material, on two opposite sides of the contact region, the isolation structure being laterally separated from the contact region by a gap
Data Source
AI summary
A microelectronic device has a Hall sensor that includes a Hall plate in a semiconductor material. The Hall sensor includes contact regions in the semiconductor material, contacting the Hall plate. The Hall sensor includes an isolation structure with a dielectric material contacting the semiconductor material, on at least two opposite sides of each of the contact regions. The isolation structure is laterally separated from the contact regions by gaps. The Hall sensor further includes a conductive spacer over the gaps, the conductive spacer being separated from the semiconductor material by an insulating layer.