Resistance-Variable Element With Copper Electrode And Ion-Conductive Layer
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Solution Overview
Problem
There is a need for a resistance-variable element with high integration, high performance, and high reliability, as well as improved miniaturization and reduced process complexity, to address the limitations of existing semiconductor devices.
Innovation Solution
A resistance-variable element is fabricated with a copper first electrode, a titanium oxide or aluminum oxide valve-metal film, an oxygen-containing ion-conductive layer primarily composed of Ta, Zr, or Hf, and a second electrode made of Ru, Ni, or Pt, where the ion-conductive layer is formed using sputtering or ALD methods to prevent copper oxidation and enhance switching properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a resistance-variable element is miniaturized for high integration, then device density is improved, but manufacturing precision and reliability deteriorate
Solution Approach 1:
The patent employs a composite structure consisting of a valve-metal oxide layer (TiOx, AlOx) combined with an ion-conductive layer (Ta-O, Zr-O, Hf-O). This composite material approach allows the device to achieve miniaturization while maintaining manufacturing precision through the complementary properties of each layer: the valve-metal oxide provides fast ion diffusion for reliable switching, while the ion-conductive layer ensures stable oxygen supply and prevents copper oxidation even at reduced dimensions
2Volume of moving object
If a resistance-variable element is miniaturized for high integration, then device density is improved, but reliability deteriorates
Solution Approach 1:
The composite structure of valve-metal oxide layer and ion-conductive layer works synergistically to maintain reliability in miniaturized devices. The valve-metal oxide (TiOx, AlOx) enables fast copper ion diffusion for reliable ON/OFF switching, while the ion-conductive layer (Ta-O, Zr-O, Hf-O) provides stable oxygen reservoir function and prevents copper oxidation, ensuring consistent performance even at small device dimensions
Solution Approach 2:
The ion-conductive layer acts as an intermediary between the copper electrode and the valve-metal oxide layer. It mediates the oxygen supply process, providing a stable oxygen reservoir that prevents direct oxidation of copper while enabling controlled oxygen diffusion to the valve-metal oxide layer, thus ensuring reliable switching operation in miniaturized devices
3Device complexity
If conventional switching elements are used, then device structure is simple, but copper oxidation occurs leading to performance degradation
Solution Approach 1:
The ion-conductive layer serves as a protective intermediary between the copper electrode and the oxygen-containing environment. It prevents direct oxidation of copper by controlling oxygen diffusion, allowing copper ions to be supplied to the valve-metal oxide layer without forming harmful copper oxides that would degrade device performance
Solution Approach 2:
The ion-conductive layer with high oxygen concentration (Ta-O, Zr-O, Hf-O) provides self-service by acting as an internal oxygen reservoir. It automatically supplies oxygen to the valve-metal oxide layer during switching operation without requiring external oxygen sources, while simultaneously protecting the copper electrode from oxidation
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 enables fast electric field diffusion of copper ions within the titanium oxide layer, improving switching properties by breaking and recovering copper bridges, thereby enhancing the reliability and performance of the resistance-variable element.
Implementation Method 1
fast electric field diffusion of copper in a titanium oxide layer under low resistance
Implementation Method 2
utilizing the migration of metal ions and electrochemical reactions between ions within an ion conductor
Implementation Method 3
utilizing the migration of metal ions and electrochemical reactions between ions within an ion conductor
Implementation Method 4
the precipitated metal forms a metal bridge between the first and second electrodes. Thus, the first electrode is connected electrically to the second electrode by the metal bridge
Implementation Method 5
the ion-conductive layer is formed using sputtering or ALD methods
Implementation Method 6
the ion-conductive layer is formed using sputtering or ALD methods
Data Source
AI summary
A resistance-variable element as disclosed has high reliability, high densification, and good insulating properties. The device provides a resistance-variable element in which a first electrode including a metal primarily containing copper, an oxide film of valve-metal, an ion-conductive layer containing oxygen and a second electrode are laminated in this order.