Hall Element Impurity Profile for Sensitivity and Breakdown Voltage
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Solution Overview
Problem
Conventional Hall elements face challenges in achieving high sensitivity, improved signal-to-noise ratio (S/N) per current, high breakdown voltage, and reliability, particularly due to low-concentration n-wells and increased junction capacitance, which complicates noise susceptibility and practical use in azimuth sensors.
Innovation Solution
A Hall element design featuring an n-type impurity region surrounded by a p-type substrate region, with a p-type impurity region located on the surface of the n-type impurity region, maintaining an impurity concentration of 1×10^16 to 3×10^16 atoms/cm^3 and a distribution depth of 3.0 μm to 5.0 μm, reducing junction capacitance and enhancing breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the impurity concentration in the n-type semiconductor region is lowered to increase carrier mobility and sensitivity, then the sensitivity of the Hall element is improved, but the breakdown voltage decreases and reliability deteriorates
Solution Approach 1:
The patent applies local quality by creating distinct regions with different impurity concentrations within the n-type semiconductor region. The magnetic sensing part has low impurity concentration (1.0×10^14/cm³ to 1.0×10^17/cm³) for high sensitivity, while the region adjacent to the p-type diffusion layer has high impurity concentration (1.0×10^19/cm³ to 1.0×10^21/cm³) for high breakdown voltage. This spatial differentiation of impurity concentration allows simultaneous optimization of both sensitivity and reliability in different locations.
2Adaptability or versatility
If the n-type semiconductor region is formed as a diffusion layer to enable substrate layer flexibility, then the degree of freedom in substrate selection is enhanced, but the junction capacitance increases and noise susceptibility worsens
Solution Approach 1:
The patent reduces noise susceptibility by creating a localized high impurity concentration region (1.0×10^19/cm³ to 1.0×10^21/cm³) adjacent to the p-type diffusion layer, which lowers the junction capacitance in the critical area where noise coupling occurs. The magnetic sensing part maintains low impurity concentration for high sensitivity. This spatial differentiation allows the n-type region to function as a diffusion layer for substrate flexibility while minimizing noise effects through localized capacitance reduction.
3Measurement precision
If a low-concentration n-well is used to achieve high sensitivity, then the S/N ratio per current is improved, but the breakdown voltage becomes insufficient and reliability decreases
Solution Approach 1:
The patent resolves the contradiction between S/N ratio and breakdown voltage by implementing local quality through impurity concentration differentiation. The magnetic sensing part uses low impurity concentration (1.0×10^14/cm³ to 1.0×10^17/cm³) to achieve high carrier mobility and excellent S/N ratio, while the region adjacent to the p-type diffusion layer uses high impurity concentration (1.0×10^19/cm³ to 1.0×10^21/cm³) to ensure sufficient breakdown voltage and reliability. This allows the low-concentration n-well to be used effectively without compromising overall device reliability.
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 design significantly increases magnetic sensitivity and S/N ratio, reduces noise susceptibility, and achieves high reliability by optimizing impurity concentration and distribution depth, making it suitable for high-performance azimuth sensors.
Implementation Method 1
a Hall element having an n-type impurity region located in a surface of a p-type semiconductor substrate layer composed of p-type silicon, the n-type impurity region functioning as a magnetic sensing part
Data Source
AI summary
A Hall element is provided which has a high sensitivity and contributes to an improvement in S/N ratio per current by using a low-concentration n-well within a suitable range. The Hall element includes a p-type semiconductor substrate layer of p-type silicon, and an n-type impurity region located in a surface of the p-type semiconductor substrate layer, the n-type impurity region functioning as a magnetic sensing part. A p-type impurity region is located in a surface of the n-type impurity region, and n-type regions are located laterally of the p-type impurity region. A p-type substrate region having a resistivity equal to that of the p-type semiconductor substrate layer is located to extend around the n-type impurity region. An impurity concentration N in the n-type impurity region functioning as the magnetic sensing part is preferably from 1×1016 to 3×1016(atoms/cm3) and a distribution depth of the impurity concentration is preferably from 3.0 μm to 5.0 μm.