Graphene Compound Hall Plate for Magnetic Field Sensor Sensitivity
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Solution Overview
Problem
Existing magnetic field sensor devices are not cost-effective and sensitive enough to detect low magnetic fluxes due to limitations in charge carrier mobility and material interactions.
Innovation Solution
A magnetic field sensor device with a semiconductor body featuring a graphene compound Hall plate, where the graphene layer is formed as a continuous, thin, two-dimensional layer parallel to the top side, integrated with a substrate and passivation layers, and optionally accompanied by silicon-boron-nitride layers, and an electrically conductive shielding layer to enhance sensitivity and reduce temperature responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional materials are used for the Hall plate, then the device structure is simple, but the charge carrier mobility is insufficient leading to low sensitivity
Solution Approach 1:
The patent uses a composite structure combining graphene compound layer with conventional semiconductor substrate (silicon or silicon-germanium). The graphene compound provides high charge carrier mobility for enhanced sensitivity, while the semiconductor substrate provides mechanical support and integration capabilities. This composite approach resolves the contradiction by achieving high sensitivity through graphene's superior electrical properties without sacrificing device manufacturability.
Solution Approach 2:
The patent changes the material parameter of the Hall plate from conventional semiconductors to graphene compound, which has fundamentally different charge carrier mobility characteristics. This parameter change enables the Hall plate to generate measurable Hall voltage even at low magnetic flux densities, directly addressing the sensitivity issue while maintaining compatibility with standard semiconductor fabrication processes.
2Measurement precision
If the graphene layer is made very thin to achieve high surface area to thickness ratio, then the sensitivity increases, but the charge carrier mobility may be reduced due to interactions with underlying layers
Solution Approach 1:
The patent introduces an intermediary layer (such as silicon oxide, silicon nitride, or silicon boron nitride) between the graphene compound layer and the semiconductor substrate. This intermediary layer acts as a buffer that reduces harmful interactions between the graphene and substrate, preserving charge carrier mobility in the thin graphene layer while still allowing the device to function properly. The intermediary layer thickness is optimized to balance sensitivity enhancement with mobility preservation.
3Measurement precision
If the Hall plate is directly connected to the substrate without gaps, then the device complexity is low, but parasitic electrical fields reduce measurement precision
Solution Approach 1:
The patent segments the Hall plate structure by creating gaps or trenches between the Hall plate regions and surrounding areas. This segmentation isolates the Hall plate from parasitic electrical fields generated by nearby conductors or substrate effects, thereby improving measurement precision. The gaps are filled with insulating materials to maintain electrical isolation while allowing continued integration with readout circuitry through controlled connections.
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 device achieves high sensitivity and cost-effectiveness in detecting low magnetic fluxes with minimal impact on charge carrier mobility, allowing for precise Hall voltage generation and reduced parasitic electrical field effects.
Implementation Method 1
a Hall plate is provided on the top side of the semiconductor body above the passivation layer, and the Hall plate has a graphene compound... a Hall plate generates a Hall voltage, provided an operating current flows through the Hall plate and part of the magnetic flux penetrates the surface of the Hall plate perpendicularly
Implementation Method 2
Tests have shown that because of the high mobility of the charge carriers in the graphene compound a Hall voltage results at low magnetic fluxes as well... the charge carrier transport occurs in one atomic layer or in a plurality of atomic layers
Data Source
AI summary
A magnetic field sensor device having a semiconductor body, whereby the semiconductor body has a top side and a bottom side, and whereby the semiconductor body has a substrate layer and a passivation layer formed above the substrate on the top side of the semiconductor body, and one or more integrated electronic components are formed in the substrate layer of the semiconductor body, and a Hall plate is provided on the top side of the semiconductor body above the passivation layer, and the Hall plate is formed of a graphene compound.