Antimony Switching Layer Buffer for Memory Reliability
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Solution Overview
Problem
Cross-point type two-terminal memory devices face challenges in achieving low half-select leakage current and high reliability due to fluctuations in switching element characteristics, particularly due to diffusion and aggregation of antimony in the switching layer during repeated data writing.
Innovation Solution
The memory device incorporates a switching layer containing an oxide of a first element, antimony, and a second element, with a specific composition and structure that suppresses diffusion and aggregation of antimony, including a mixture of oxides such as zirconium oxide, antimony, and aluminum or gallium, to stabilize the switching element characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switching layer containing antimony is used to achieve low leakage current, then half-select leakage current is reduced, but antimony diffusion and aggregation occur during repeated data writing, degrading switching element characteristics
Solution Approach 1:
A buffer layer containing aluminum oxide or gallium oxide is introduced between the antimony-containing switching layer and the conductive layer. This buffer layer acts as an intermediary that prevents direct contact and interaction between antimony and the conductive layer, thereby suppressing antimony diffusion while maintaining the low leakage current characteristic of the switching layer.
Solution Approach 2:
The harmful diffusion behavior of antimony is extracted and isolated by placing it in a separate switching layer, physically separated from the conductive layer by the buffer layer. This extraction prevents antimony from migrating into the conductive layer during repeated data writing operations, maintaining compositional stability.
2Object-generated harmful factors
If antimony is used in the switching layer to achieve low leakage current, then half-select leakage current is suppressed, but antimony aggregates form during repeated operations, reducing switching element reliability
Solution Approach 1:
The buffer layer serves as a protective intermediary that prevents antimony aggregation by blocking the path for antimony migration toward the conductive layer. This maintains the harmful factor (low leakage current) while preventing the reliability-degrading aggregation effect.
Solution Approach 2:
The buffer layer is pre-installed between the switching layer and conductive layer to provide protective cushioning against antimony diffusion and aggregation before repeated data writing operations begin. This preventive measure ensures that antimony remains contained in the switching layer throughout the device operational life.
Data Source
AI summary
A memory device of embodiments includes a memory cell including: a first conductive layer; a second conductive layer; a third conductive layer provided between the first conductive layer and the second conductive layer; a variable resistance layer provided between the first conductive layer and the third conductive layer; and a switching layer provided between the third conductive layer and the second conductive layer. The switching layer contains antimony (Sb), a second element, adn an oxide of a first element. The first element is at least one element selected from a group consisting of zirconium (Zr), hafnium (Hf), yttrium (Y), tantalum (Ta), lanthanum (La), cerium (Ce), magnesium (Mg), and titanium (Ti). The second element is at least one element selected from a group consisting of aluminum (Al), zinc (Zn), and gallium (Ga).