Cross Point Memory Cell Arrays with Offset Multi-Resistive Layers
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Solution Overview
Problem
Phase change materials used in cross point memory cells face mechanical weakness as their thickness increases, posing challenges during manufacturing, particularly in forming arrays of non-volatile memory cells.
Innovation Solution
The method involves forming arrays of cross point memory cells by patterning inner and outer multi-resistive state materials with conductive electrodes, using dielectric materials to fill spaces and optimize the composition and thickness of electrode materials to enhance structural integrity and conductivity, allowing for the formation of stable memory cell arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of phase change materials is increased to improve memory cell stability and data retention, then the mechanical strength deteriorates making manufacturing difficult
Solution Approach 1:
The patent employs a composite structure consisting of multiple layers including phase change material layers, dielectric layers, and conductive electrode layers. This composite architecture provides mechanical support and structural integrity while maintaining the functional properties of the phase change material, thereby resolving the contradiction between thickness-related stability and mechanical strength.
Solution Approach 2:
The memory cell structure is divided into multiple discrete layers and regions, including inner and outer phase change material regions, dielectric layers, and conductive elements. This segmentation allows each layer to be optimized independently - the phase change material can be made thick enough for stability while being supported by thinner structural layers that provide mechanical strength.
2Manufacturing precision
If the thickness of phase change materials is increased to ensure proper formatting and processing, then the mechanical weakness increases causing processing challenges
Solution Approach 1:
The patent incorporates preliminary structural support elements such as dielectric layers and conductive electrodes that are formed before and alongside the phase change material layers. These pre-formed structures provide mechanical support during subsequent processing steps, enabling accurate formatting and processing of thicker phase change material regions without compromising ease of manufacture.
3Reliability
If electrode material thickness is optimized to enhance conductivity, then the structural integrity may be compromised
Solution Approach 1:
The electrode structure is designed as a composite of multiple conductive layers with different thicknesses and material compositions. This allows optimization of electrical conductivity through the conductive layers while the overall electrode structure, supported by dielectric and phase change material layers, maintains structural integrity.
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 creation of robust and efficient cross point memory cell arrays that can withstand processing and maintain multi-resistive states effectively, addressing the mechanical weakness issues of phase change materials.
Implementation Method 1
The crystallization temperature and the melting temperature are obtained by causing an electric current to flow through the heater material, thus heating the phase change material.
Implementation Method 2
Such memory uses a reversibly programmable material that has the property of switching between two different phases, for example between an amorphous, disorderly phase and a crystalline or polycrystalline, orderly phase.
Data Source
AI summary
An array of cross point memory cells comprises spaced elevationally inner first lines, spaced elevationally outer second lines which cross the first lines, and a multi-resistive state region elevationally between the first and second lines where such cross. Individual of the multi-resistive state regions comprise elevationally outer multi-resistive state material and elevationally inner multi-resistive state material that are electrically coupled to one another. The inner multi-resistive state material has opposing edges in a vertical cross-section. The outer multi-resistive state material has opposing edges in the vertical cross-section that are laterally offset relative to the opposing edges of the inner multi-resistive state material in the vertical cross-section. Methods are also disclosed.