Metal Chalcogenide Select Device for Leakage Control

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Solution Overview

Problem

Cross-point memory arrays face significant current leakage issues due to non-selected cells, leading to power wastage and data errors, which existing technologies struggle to mitigate effectively.

Innovation Solution

A metal chalcogenide-containing device with an electric-field-modifying region between electrodes, comprising a composition with a high bandgap and low dielectric constant, such as gallium oxide or gadolinium oxide, to increase threshold voltage without excessive electric field exposure, enabling controlled current flow and reduced leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional memory cells are used in cross-point arrays, then memory storage is achieved, but substantial current leakage occurs through non-selected cells

Engineering Contradiction:
Improvecurrent leakageVSAvoiddata accuracy
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent introduces a select device comprising metal chalcogenide-containing material positioned between the memory cell and electrodes. This intermediary component controls current flow through the memory cell, enabling selective activation while blocking leakage current in non-selected cells. The metal chalcogenide material acts as a threshold switch that only conducts above a specific voltage threshold, effectively preventing the harmful leakage current that causes power waste and data errors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If threshold voltage is increased to reduce leakage, then off-state leakage decreases, but electric field exposure increases excessively

Engineering Contradiction:
Improveleakage currentVSAvoidelectric field exposure
Core Design Contradiction:
Loss of energyVSStress or pressure

Solution Approach 1:

The patent modifies the electrical parameters of the select device by incorporating metal chalcogenide-containing material with specific properties. This material enables the device to maintain a high threshold voltage (reducing leakage) while managing the electric field distribution through its unique electrical characteristics. The metal chalcogenide material's ability to switch between high and low resistance states allows optimization of both threshold voltage and electric field exposure parameters.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If diodes or select devices are added to control current, then leakage from un-selected cells is reduced, but device complexity increases

Engineering Contradiction:
Improveleakage currentVSAvoidselect device structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges the select device functionality directly into the memory cell structure by positioning metal chalcogenide-containing material between the memory cell and electrodes. This integration approach combines the threshold switching function with the memory cell architecture, reducing the need for separate, complex select devices while effectively controlling current flow and minimizing leakage.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively reduces off-state leakage and enhances current density in the 'on' state, improving data retention and storage efficiency in memory arrays by tailoring the threshold voltage and electric field distribution.

Implementation Method 1

a metal chalcogenide-containing device with an electric-field-modifying region between electrodes

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 2

comprising a composition with a high bandgap and low dielectric constant

Methodology Applied
Scientific EffectBandgap:

Implementation Method 3

comprising a composition with a high bandgap and low dielectric constant

Methodology Applied
Scientific EffectDielectric constant: Dielectric Permittivity

Implementation Method 4

Devices containing semiconducting chalcogenides having electrochemically-active metal ions

Methodology Applied
Scientific EffectElectrochemical activity:

Data Source

PatentEP3198646B1Devices containing metal chalcogenides
Publication Date: 2019.11.27 MICRON TECHNOLOGY INC
  • EP3198646B1 patent drawingFigure 1~3
  • EP3198646B1 patent drawingFigure 4~5
  • EP3198646B1 patent drawingFigure 6~7

AI summary

Some embodiments include a device having a conductive material, a metal chalcogenide-containing material, and a region between the metal chalcogenide-containing material and the conductive material. The region contains a composition having a bandgap of at least about 3.5 electronvolts and a dielectric constant within a range of from about 1.8 to 25. Some embodiments include a device having a first electrode, a second electrode, and a metal chalcogenide-containing material between the first and second electrodes. The device also includes an electric-field-modifying region between the metal chalcogenide-containing material and one of the first and second electrodes. The electric-field-modifying region contains a composition having a bandgap of at least about 3.5 electronvolts having a low dielectric constant and a low conduction band offset relative to a workfunction of metal of the metal chalcogenide-containing material.