Nonvolatile Memory Cell With Diffusion Barrier Film
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Solution Overview
Problem
Current nonvolatile memory devices face challenges in achieving increased integration density while maintaining effective voltage-current characteristics and preventing diffusion of conductive materials.
Innovation Solution
The design includes a nonvolatile memory cell with first and second interlayer insulating films, a first electrode penetrating both films, a resistance change film along the electrode's side surface, and a second electrode with a conductive metal film and a diffusion barrier, where the electrodes have a work function of 4.0 to 6 eV and the resistance change film is a metal oxide with N-type semiconductor characteristics, allowing for increased integration density and efficient voltage-current switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional nonvolatile memory device structures are used, then device functionality is maintained, but integration density is limited
Solution Approach 1:
The patent implements a nested structure where the resistance change film is formed along the side surface of the first electrode, and the second electrode is positioned between the interlayer insulating films. This nested arrangement allows multiple functional layers to occupy overlapping spatial regions, increasing integration density without proportionally increasing device footprint
Solution Approach 2:
The resistance change film transitions from a planar configuration to a three-dimensional structure that extends along the side surface of the first electrode. This vertical dimension utilization allows the memory cell to store information in a spatial configuration that increases density without requiring additional lateral space
2Reliability
If metal conductive films are used in electrodes, then electrical conductivity is improved, but diffusion of conductive material occurs
Solution Approach 1:
The patent introduces a diffusion preventing film as an intermediary layer between the metal conductive film and surrounding materials. This intermediate layer serves as a barrier that allows electrical conductivity to be maintained while preventing the harmful diffusion of metal atoms into adjacent interlayer insulating films and resistance change film
3Ease of operation
If resistance change film composition is altered for N-type characteristics, then voltage-current switching is improved, but material stability may be affected
Solution Approach 1:
The patent achieves N-type semiconductor characteristics by controlling the oxygen deficiency parameter in the metal oxide resistance change film. By adjusting the oxygen content during fabrication or through subsequent annealing processes, the film exhibits desired N-type conductivity and voltage-current switching characteristics while maintaining structural stability through controlled composition
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 configuration enhances integration density and enables efficient voltage-current characteristics, ensuring that the resistance change film remains unchanged under inhibit voltage and changes under switching voltage, effectively programming the memory cells without the need for a diode, thereby improving data storage capabilities.
Implementation Method 1
a diffusion preventing film which prevents diffusion of a conductive material contained in the conductive film
Implementation Method 2
the resistance change film is a metal oxide film having N-type semiconductor characteristics by a lack of oxygen
Data Source
AI summary
A nonvolatile memory cell includes first and second interlayer insulating films which are separated from each other and are stacked sequentially, a first electrode which penetrates the first interlayer insulating film and the second interlayer insulating film, a resistance change film which is formed along a side surface of the first electrode and extends parallel to the first electrode, and a second electrode which is formed between the first interlayer insulating film and the second interlayer insulating film. The second electrode includes a conductive film which is made of metal and a diffusion preventing film which prevents diffusion of a conductive material contained in the conductive film.