Cup-Shaped Heating Electrode Phase Change Memory Device
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Solution Overview
Problem
Conventional phase change memory (PCM) device fabrication processes face challenges in achieving higher device density due to limitations in photolithography resolution and seam problems when minimizing device area, which affect electrical and thermal performance.
Innovation Solution
A phase change memory device is fabricated using a cup-shaped heating electrode with a pair of double spacers, comprising a phase change material spacer and an insulating material spacer, to control the contact area and improve device density, while protecting the phase change material from damage during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the contact area between phase change material and bottom electrode is minimized to increase device density, then device density is improved, but seam problems occur when the critical dimension is too small
Solution Approach 1:
The patent transitions from a conventional planar contact structure to a three-dimensional cup-shaped bottom electrode structure. This dimensional change allows the phase change material to be contained within the cup-shaped electrode, providing structural support and preventing seam formation while maintaining a small footprint area, thus achieving both high device density and reliable contact
Solution Approach 2:
The phase change material is nested within the cup-shaped bottom electrode structure, where the material is contained inside the electrode cavity. This nesting approach ensures that the phase change material maintains proper contact with the electrode walls and bottom surface, preventing seam formation while minimizing the overall device area
2Area of stationary object
If photolithography process is used to minimize device area, then device area is reduced, but the process becomes unsuitable when critical dimension is below 0.1 μm
Solution Approach 1:
The invention moves from two-dimensional planar patterning limits to three-dimensional structure formation using the cup-shaped electrode. This allows the device footprint to be minimized in the planar dimensions while the vertical dimension provides the necessary functional volume, effectively bypassing photolithography resolution limits for critical dimensions
3Quantity of substance
If conventional fabrication process is used to achieve higher device density, then device density is improved, but electrical and thermal performance deteriorates
Solution Approach 1:
The cup-shaped bottom electrode structure provides locally optimized quality by concentrating the phase change material and heating electrode in close proximity within the cup structure. This localized configuration ensures efficient thermal coupling and electrical contact while maintaining overall high device density through compact footprint
Solution Approach 2:
The nested configuration of phase change material within the cup-shaped electrode ensures optimal thermal and electrical contact between components. The material is surrounded by the electrode structure, maximizing heat transfer efficiency and electrical connectivity while minimizing the device footprint
Data Source
AI summary
A phase change memory device is provided. The phase change memory device comprises a substrate. An electrode layer is on the substrate. A phase change memory structure is on the electrode layer and electrically connected to the electrode layer, wherein the phase change memory structure comprises a cup-shaped heating electrode on the electrode layer. An insulating layer is on the cup-shaped heating electrode along a first direction covering a portion of the cup-shaped heating electrode. An electrode structure is on the cup-shaped heating electrode along a second direction covering a portion of the insulating layer and the cup-shaped heating electrode. A pair of double spacers is on a pair of sidewalls of the electrode structure covering a portion of the cup-shaped heating electrode, wherein the double spacer comprises a phase change material spacer and an insulating material spacer on a sidewall of the phase change material spacer.