Vertical Hall Element Uniform Impurity Layer
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Solution Overview
Problem
Vertical Hall elements face challenges in enhancing sensitivity and reducing offset voltage due to narrow current flow paths and uneven impurity concentration distributions, leading to limited magnetic sensitivity and increased offset voltage.
Innovation Solution
A semiconductor device with a vertical Hall element featuring a uniformly distributed impurity concentration semiconductor layer, higher impurity diffusion layers, and electrode isolation diffusion layers that spread depletion layers to facilitate current flow across the substrate, increasing current width and reducing resistance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an impurity diffusion layer with concentrated impurity distribution is used in vertical Hall element, then current flow path is confined, but sensitivity is reduced due to narrow current width
Solution Approach 1:
The patent applies local quality by creating different impurity concentration zones: a high-concentration impurity diffusion layer at the surface for current confinement, and a uniformly distributed lower-concentration semiconductor layer beneath for wide current flow. This spatial variation in material properties allows simultaneous achievement of current confinement and wide current flow path.
Solution Approach 2:
The patent transitions from two-dimensional current flow (parallel to substrate surface) to three-dimensional current flow by utilizing the depth dimension. Current flows downward into the uniformly distributed impurity concentration region, then spreads horizontally, and finally returns upward, creating a three-dimensional current path that increases effective width while maintaining confinement.
2Measurement precision
If electrode isolation diffusion layers are added to isolate electrodes, then current confinement is improved, but offset voltage increases due to uneven current paths
Solution Approach 1:
The patent applies homogeneity by ensuring the semiconductor layer has uniformly distributed impurity concentration throughout. This uniformity creates equal resistance paths for current flowing in opposite directions, causing offset voltages to cancel each other out and reducing net offset voltage to minimal levels.
Solution Approach 2:
The patent uses symmetric placement of electrode isolation diffusion layers on both sides of the magnetism sensing portion. This symmetric copying creates mirror-image current paths that generate equal and opposite offset voltages, which cancel each other out to reduce overall offset voltage.
3Measurement precision
If current flows through uneven concentration regions, then resistance varies causing offset voltage, but uniform concentration reduces sensitivity enhancement
Solution Approach 1:
The patent segments the semiconductor structure into two distinct functional regions: an impurity diffusion layer for current injection and confinement, and a uniformly distributed impurity concentration semiconductor layer for low-resistance current flow. This segmentation allows each region to optimize its specific function without compromising the other.
Solution Approach 2:
The patent prepares the semiconductor layer with uniformly distributed impurity concentration before forming the impurity diffusion layer on top. This preliminary preparation ensures that when current is subsequently injected, it flows through a pre-established low-resistance uniform path, minimizing resistance variations and offset voltages from the start.
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 enhances magnetic sensitivity by widening the current flow path and reduces offset voltage through uniform resistance distribution, allowing for more effective magnetic field detection with improved sensitivity and reduced electrical noise.
Implementation Method 1
the electrode isolation diffusion layers of the first conductivity type each formed between two electrodes out of the plurality of electrodes on the surface of the impurity diffusion layer to isolate the plurality of electrodes from one another
Implementation Method 2
a vertical Hall element for detection of a magnetic field component parallel to a substrate surface
Implementation Method 3
uniform resistance distribution, allowing for more effective magnetic field detection with improved sensitivity and reduced electrical noise
Data Source
AI summary
A vertical Hall element having an improved sensitivity and reduced offset voltage includes: a second conductivity type semiconductor layer formed on a semiconductor substrate and having an impurity concentration that is distributed uniformly; a second conductivity type impurity diffusion layer formed on the semiconductor layer and having a concentration higher than in the semiconductor layer; a plurality of electrodes formed in a straight line on a surface of the impurity diffusion layer, and each formed from a second conductivity type impurity region that is higher in concentration than the impurity diffusion layer; and a plurality of first conductivity type electrode isolation diffusion layers each formed between two electrodes out of the plurality of electrodes on the surface of the impurity diffusion layer, to isolate the plurality of electrodes from one another.