Hall Plate Sensitivity via Ultra-Thin Sputtering

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Solution Overview

Problem

Current Hall Effect magnetic field sensing elements lack sufficient sensitivity due to limitations in carrier concentration and thickness of the Hall plate material.

Innovation Solution

A Hall plate with a thickness of 0.5 nanometers to 100 nanometers and a carrier concentration of 10^19 to 10^26 carriers/cm^3, made from materials like copper oxide, is fabricated using a sputtering process with an adhesion layer and passivation, enhancing sensitivity by a factor of ten to a thousand compared to existing elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the Hall plate thickness is increased to improve signal strength, then the sensitivity should improve, but the carrier concentration decreases and sensitivity deteriorates

Engineering Contradiction:
ImprovesensitivityVSAvoidcarrier concentration
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by optimizing the thickness of the Hall plate to a specific range (5nm-100nm) and controlling the carrier concentration within 10^19 to 10^26 carriers/cm³. This resolves the contradiction by identifying the optimal parameter window where both sufficient thickness for signal generation and adequate carrier concentration for sensitivity are simultaneously achieved.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures including the Hall plate formed from metal oxides or metal nitrides combined with adhesion layers (such as titanium nitride) and passivation layers. This composite approach allows the Hall plate to achieve enhanced sensitivity through material composition optimization while maintaining structural integrity and electrical properties.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If a thin Hall plate is used to maintain high carrier concentration, then sensitivity improves, but the Hall plate becomes too thin to fabricate and handle

Engineering Contradiction:
ImprovesensitivityVSAvoidfabrication difficulty
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent resolves fabrication difficulty by establishing the thickness parameter within 5nm-100nm, which is thin enough to maintain high carrier concentration and sensitivity but thick enough to be manufacturable using conventional semiconductor fabrication techniques including sputtering, chemical vapor deposition, and lithography.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces adhesion layers (such as titanium nitride) as intermediary structures between the substrate and the thin Hall plate. These adhesion layers provide mechanical support and handling stability to the ultra-thin Hall plate while not significantly interfering with the Hall effect sensing function, thereby enabling fabrication and integration of very thin sensitive structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If conventional materials are used in the Hall plate, then fabrication is straightforward, but sensitivity is insufficient

Engineering Contradiction:
ImprovesensitivityVSAvoidmaterial selection flexibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent employs composite material structures including the Hall plate formed from metal oxides or metal nitrides combined with adhesion layers (such as titanium nitride) and passivation layers. This composite approach allows the Hall plate to achieve enhanced sensitivity through material composition optimization while maintaining structural integrity and electrical properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by optimizing the thickness of the Hall plate to a specific range (5nm-100nm) and controlling the carrier concentration within 10^19 to 10^26 carriers/cm³. This resolves the contradiction by identifying the optimal parameter window where both sufficient thickness for signal generation and adequate carrier concentration for sensitivity are simultaneously achieved.

Inventive Principle:
Principle #35Parameter changes

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 improved Hall plate significantly increases the sensitivity of Hall Effect sensing elements, allowing for more precise magnetic field detection, with the Hall Voltage being proportional to the magnetic field strength.

Implementation Method 1

Hall Effect magnetic field sensing elements are known... Hall Effect element includes a so-called 'Hall plate'... Hall Voltage being proportional to the magnetic field strength

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

the Hall plate is fabricated such that it has a thickness of .5 nanometers to 100 nanometers... fabricated using a sputtering process

Methodology Applied
Scientific EffectSputtering: Sputtering

Data Source

PatentEP3275025B1Hall effect sensing element
Publication Date: 2020.05.06 ALLEGRO MICROSYSTEMS LLC
  • EP3275025B1 patent drawingFigure 1
  • EP3275025B1 patent drawingFigure 2
  • EP3275025B1 patent drawingFigure 3

AI summary

In one aspect, a Hall Effect sensing element (100) includes a Hall plate (114) having a thickness less than about 100 nanometers an adhesion layer (110) directly in contact with the Hall plate and having a thickness in a range about 0.1 nanometers to 5 nanometers. In another aspect, a sensor includes a Hall Effect sensing element. The Hall Effect sensing element (100') includes a substrate (102) that includes one of a semiconductor material or an insulator material, an insulation layer (106) in direct contact with the substrate, an adhesion layer (110) having a thickness in a range of about.1 nanometers to 5 nanometers and in direct contact with the insulation layer and a Hall plate (114) in direct contact with the adhesion layer and having a thickness less than about 100 nanometers.