Trap Passivation in Metal Oxide Memory Cells
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Solution Overview
Problem
Existing non-volatile storage devices require high voltages and currents to switch between resistance states, leading to stress on the memory cells and limiting the number of set/reset cycles, as well as increasing power requirements.
Innovation Solution
The use of a reversible resistivity-switching element with a metal oxide region and a bi-layer top electrode, incorporating oxygen diffusion resistant materials and trap passivation, and a bi-layer capping layer to reduce oxidation and improve thermal resistance, thereby lowering the switching voltages and currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage and current are applied to switch between resistance states, then the switching function is achieved, but stress on memory cells increases and the number of set/reset cycles is limited
Solution Approach 1:
The patent modifies the physical and chemical parameters of the memory cell structure by incorporating a bi-layer top electrode with oxygen diffusion resistant material and trap passivation material. These parameter changes in the electrode composition and interface properties reduce the stress required for resistance state switching, thereby increasing the number of viable set/reset cycles while maintaining the switching function.
Solution Approach 2:
The patent employs composite material structures in the bi-layer top electrode, combining conductive material with oxygen diffusion resistant material and trap passivation material. This composite approach creates a more stable interface that reduces degradation from high voltage/current stress, improving reliability and cycle life without sacrificing switching capability.
2Power
If high voltage and current are applied to switch between resistance states, then the switching function is achieved, but power requirements increase
Solution Approach 1:
The patent changes the electrical parameters at the electrode-metal oxide interface through the introduction of trap passivation material and oxygen diffusion resistant layers. These parameter modifications reduce the voltage and current thresholds needed for switching, thereby lowering power requirements while preserving the reliability of the switching function.
3Use of energy by moving object
If trap passivation material is added to the top electrode, then switching voltages and currents are reduced, but device complexity increases
Solution Approach 1:
The patent merges multiple functional materials into the top electrode structure - combining conductive material, oxygen diffusion resistant material, and trap passivation material into a unified bi-layer electrode assembly. This merging approach achieves reduced switching voltages and currents while managing device complexity through integrated design rather than separate components.
Solution Approach 2:
The bi-layer top electrode serves multiple functions simultaneously: it provides electrical conductivity, prevents oxygen diffusion into the metal oxide, and passivates interface traps. This multi-functionality reduces switching parameters while avoiding the need for separate dedicated components, thereby managing device complexity.
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 reduces the stress on memory cells, increases the number of set/reset cycles, and decreases power requirements by lowering the switching voltages and currents, enhancing the performance and reliability of non-volatile storage devices.
Implementation Method 1
adding a trap passivation material to one or more of the first electrically conductive material, the metal oxide region, or the second electrically conductive material. The passivation material passivates traps at least one of a first interface between the metal oxide region and the bottom electrode or a second interface between the metal oxide region and the top electrode
Implementation Method 2
depositing an oxygen diffusion resistant material over the top electrode... The oxygen diffusion resistant material prevents formation of oxide on the top electrode
Data Source
AI summary
Non-volatile storage elements having a reversible resistivity-switching element and techniques for fabricating the same are disclosed herein. The reversible resistivity-switching element may be formed by depositing an oxygen diffusion resistant material (e.g., heavily doped Si, W, WN) over the top electrode. A trap passivation material (e.g., fluorine, nitrogen, hydrogen, deuterium) may be incorporated into one or more of the bottom electrode, a metal oxide region, or the top electrode of the reversible resistivity-switching element. One embodiment includes a reversible resistivity-switching element having a bi-layer capping layer between the metal oxide and the top electrode. Fabricating the device may include depositing (un-reacted) titanium and depositing titanium oxide in situ without air break. One embodiment includes incorporating titanium into the metal oxide of the reversible resistivity-switching element. The titanium might be implanted into the metal oxide while depositing the metal oxide, or after deposition of the metal oxide.