Germanium Telluride Phase Change Material Deposition

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Solution Overview

Problem

Current methods for forming phase change materials, particularly for phase change memory circuitry, face challenges in scaling down while maintaining reliability and density, as existing deposition techniques may not ensure uniformity and stoichiometry of materials like GeTe and GeSbTe, affecting the electrical resistance switching properties.

Innovation Solution

A method involving chemical vapor deposition (CVD) and atomic layer deposition (ALD) to form phase change materials comprising germanium and tellurium, where germanium and tellurium precursors are used to deposit a GeTe or GeSbTe compound with controlled thickness and composition, ensuring self-limiting growth and uniformity, and incorporating additional elements like antimony to enhance properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional deposition techniques are used to form phase change materials, then the deposition process is simple and fast, but the uniformity and stoichiometry of the material are poor, affecting electrical resistance switching properties

Engineering Contradiction:

Improveuniformity and stoichiometry of phase change materialVSAvoiddeposition process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The deposition process is segmented into multiple sequential steps: first depositing a germanium layer, then a tellurium layer, followed by annealing to form GeTe, and optionally repeating for GeSbTe. This segmentation allows precise control over composition and stoichiometry of each layer, ensuring uniform phase change material formation while managing process complexity through systematic breakdown

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Germanium and tellurium layers are deposited in advance with controlled thicknesses before annealing. This preliminary action ensures the correct stoichiometric ratios are established before the phase change reaction, preventing composition variability and ensuring uniform electrical resistance switching properties in the final product

Inventive Principle:

Principle #10Preliminary action

2Productivity

If device size is reduced to increase density, then more circuitry can be packed into smaller space, but reliability of operation deteriorates

Engineering Contradiction:

Improvecircuitry densityVSAvoidoperational reliability of scaled devices

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention changes material parameters by using specific compositions (GeTe, GeSbTe) with well-defined phase change properties. By controlling the stoichiometry and purity of these materials through segmented deposition, the phase change characteristics remain reliable even when device dimensions are reduced, enabling high density without sacrificing operational reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The use of composite phase change materials like GeSbTe combines multiple elements with complementary properties. This composite approach enhances material stability and phase change reliability, allowing smaller device sizes to maintain operational reliability through superior material performance

Inventive Principle:

Principle #40Composite materials

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 approach enables the formation of reliable and scalable phase change memory circuitry with improved electrical resistance switching, allowing for denser and more reliable integrated circuitry, suitable for applications in rewritable media and advanced memory devices.

Implementation Method 1

chemical vapor deposition (CVD) and atomic layer deposition (ALD) to form phase change materials comprising germanium and tellurium

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 2

phase change materials comprising germanium and tellurium

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS8765519B2Methods of forming phase change materials and methods of forming phase change memory circuitry

Publication Date: 2014.07.01 OVONYX MEMORY TECHNOLOGY LLC

AI summary

A method of forming a phase change material which having germanium and tellurium therein includes depositing a germanium-containing material over a substrate. Such material includes elemental-form germanium. A gaseous tellurium-comprising precursor is flowed to the germanium-comprising material and tellurium is removed from the gaseous precursor to react with the elemental-form germanium in the germanium-comprising material to form a germanium and tellurium-comprising compound of a phase change material over the substrate. Other implementations are disclosed.