Isolated Hall Sensor Trench Isolation Crosstalk
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Solution Overview
Problem
Existing Hall sensor structures face challenges in minimizing crosstalk and transient properties, particularly at low operating currents and low doping levels, which affect sensitivity and switch-on behavior.
Innovation Solution
An isolating Hall sensor structure is developed with a substrate layer, oxide layer, and semiconductor region, featuring trenches that isolate box regions electrically, and second semiconductor contact regions connected to a reference potential to suppress crosstalk and surface effects, enhancing sensitivity and reducing threshold voltage implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If trenches are introduced to isolate box regions electrically, then crosstalk suppression is improved, but device complexity increases
Solution Approach 1:
The semiconductor region is divided into multiple electrically isolated box regions by introducing trenches that extend from the top surface to the buried oxide layer. Each box region contains separate Hall sensor elements, achieving electrical isolation and crosstalk suppression through physical segmentation of the semiconductor substrate.
Solution Approach 2:
The trenches act as intermediary structures filled with dielectric material or doped polysilicon, serving as electrical barriers between adjacent box regions. This intermediary layer prevents charge carrier diffusion and electrical coupling between neighboring sensor elements, effectively suppressing crosstalk.
2Measurement precision
If second semiconductor contact regions are added to suppress crosstalk, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Second semiconductor contact regions of opposite conductivity type are selectively introduced at specific locations within the box regions, particularly near the trenches. These localized contact regions provide charge compensation and suppress surface effects only where needed, without requiring comprehensive modification of the entire device structure.
Solution Approach 2:
The second semiconductor contact regions are pre-configured to counteract crosstalk and surface effects before they can degrade measurement precision. By establishing these compensating contact regions during fabrication, the device is pre-conditioned to resist harmful electrical interference and charge accumulation at the BOX-trench interfaces.
3Measurement precision
If low doping levels are used to increase sensitivity, then measurement precision is improved, but transient properties worsen
Solution Approach 1:
The doping concentration in the box regions is optimized to low levels to maximize sensitivity and reduce thermal noise. However, the trenches are filled with doped polysilicon and second contact regions are introduced to compensate for the reduced doping, maintaining reliable transient response and preventing temporary depletion effects during sensor operation.
Solution Approach 2:
The device employs a composite structure combining lightly-doped semiconductor regions for high sensitivity with heavily-doped polysilicon trench fillers and oppositely-doped contact regions. This composite approach allows the main sensor region to operate at low doping for maximum sensitivity while the doped auxiliary structures provide the necessary charge carriers for stable transient behavior.
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 improves transient properties, suppresses drift in measured values, and increases sensitivity by eliminating temporary depletion and surface effects, even at low doping levels and low operating currents.
Implementation Method 1
A Hall sensor structure comprising a plurality of Hall sensor elements
Data Source
AI summary
An isolating Hall sensor structure having a support structure made of a substrate layer and an oxide layer, a semiconductor region of a first conductivity type which is integrally connected to a top side of the oxide layer, at least one trench extending from the top side of the semiconductor region to the oxide layer of the support structure, at least three first semiconductor contact regions of the first conductivity type, each extending from a top side of the semiconductor region into the semiconductor region. The at least one trench surrounds a box region of the semiconductor region. The first semiconductor contact regions are each arranged in the box region of the semiconductor region and are each spaced apart from one another. A metallic connection contact layer is arranged on each first semiconductor contact region.