RRAM Bottom Electrode Oxygen Diffusion Barrier
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Solution Overview
Problem
Resistive random access memory (RRAM) devices face issues with non-uniform resistance and conversion due to oxygen diffusion, leading to reliability and yield problems, as oxygen from the interlayer dielectric layer can cause oxidation reactions and affect the formation of oxygen vacancy filaments.
Innovation Solution
A resistive random access memory structure is developed with an oxygen diffusion barrier layer and oxygen-rich layers to prevent oxygen diffusion, including a trilayer bottom electrode structure and additional oxygen-rich layers to block oxygen, ensuring uniform resistance and conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an interlayer dielectric layer is used in RRAM structure, then the device can be fabricated with standard semiconductor processes, but oxygen diffusion from the dielectric layer causes non-uniform resistance and reduces device reliability
Solution Approach 1:
An oxygen diffusion barrier layer is introduced as an intermediary between the interlayer dielectric layer and the bottom electrode. This barrier layer prevents oxygen from the dielectric from diffusing into the electrode and resistive switching layer, thereby eliminating the root cause of non-uniform resistance while maintaining compatibility with standard semiconductor fabrication processes.
Solution Approach 2:
The bottom electrode is designed as a composite structure consisting of multiple layers including a first electrode layer, an oxygen-rich layer, and a second electrode layer. This composite structure provides both mechanical stability and controlled oxygen diffusion characteristics, ensuring uniform resistance formation while maintaining ease of manufacture through sequential deposition processes.
2Device complexity
If oxygen diffusion is allowed from the interlayer dielectric layer, then the fabrication process is simpler, but the resistance switching becomes non-uniform across the wafer
Solution Approach 1:
The oxygen diffusion barrier layer serves as a mediator that controls oxygen transport between the interlayer dielectric and the bottom electrode. By preventing uncontrolled oxygen diffusion, this intermediary layer ensures uniform oxygen distribution during the formation of oxygen vacancy filaments, thereby achieving consistent resistance switching characteristics across the entire wafer.
Solution Approach 2:
The bottom electrode structure incorporates an oxygen-rich layer with specific oxygen concentration and thickness parameters. By carefully controlling these parameters, the structure enables precise control over oxygen diffusion during resistive switching layer formation, ensuring uniform resistance characteristics while maintaining a relatively simple overall device structure.
3Manufacturing precision
If oxygen-rich layers are added to the bottom electrode structure, then oxygen diffusion is blocked and resistance uniformity improves, but the number of layers and process steps increases
Solution Approach 1:
The oxygen-rich layer is strategically positioned only at the interface between the bottom electrode and the resistive switching layer, where oxygen diffusion control is most critical. This localized approach provides the necessary oxygen diffusion barrier function without adding complexity to other parts of the device structure, maintaining manufacturing precision while limiting the increase in overall device complexity.
Solution Approach 2:
The bottom electrode is designed as a composite structure with distinct functional layers: a first electrode layer for electrical connection, an oxygen-rich layer for controlled oxygen diffusion, and a second electrode layer for additional electrical functionality. This composite design achieves superior resistance uniformity by assigning specific functions to each layer, while the overall structure remains compatible with standard multi-layer deposition processes.
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
The solution enhances the yield and reliability of RRAM devices by preventing oxygen-induced non-uniformity, allowing for controlled resistance switching and improved performance across the wafer.
Implementation Method 1
An oxygen diffusion barrier layer is formed on the ILD layer
Implementation Method 2
oxygen from the interlayer dielectric layer can cause oxidation reactions and affect the formation of oxygen vacancy filaments
Implementation Method 3
oxygen from the interlayer dielectric layer can cause oxidation reactions and affect the formation of oxygen vacancy filaments
Data Source
AI summary
A resistive random access memory (RRAM) structure and its forming method are provided, which includes an interlayer dielectric layer on a substrate. The interlayer dielectric layer is a dielectrics including oxygen. The RRAM structure also includes an oxygen-diffusion barrier layer on the interlayer dielectric layer, and a bottom electrode layer on the oxygen-diffusion barrier layer. The bottom electrode layer includes a first electrode layer, a first oxygen-rich layer on the first electrode layer, and a second electrode layer on the first oxygen-rich layer. The RRAM structure also includes a resistance switching layer on the bottom electrode layer, and a top electrode layer on the resistance switching layer.