Variable Resistance Element With Insulating Spacer
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Solution Overview
Problem
The variable resistance element in existing technologies faces challenges in reducing leakage current during the off-state while maintaining programming characteristics, particularly when the variable resistance film is formed at the end of copper wiring, leading to increased leakage current from the wiring side surface.
Innovation Solution
A variable resistance element is designed with a first electrode covered by a barrier metal, a variable resistance film on top, and a second electrode, with an insulating film spacer between the barrier metal and the variable resistance film, which reduces leakage current by separating the electric field and preventing copper ion diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the variable resistance film is formed at the end of copper wiring to enable programming operation, then the programming characteristic is improved, but leakage current from the wiring side surface increases
Solution Approach 1:
A barrier metal layer is introduced as an intermediary between the copper wiring and the variable resistance film. This barrier metal prevents copper ion diffusion into the variable resistance film while still allowing the programming operation to function, thereby eliminating the leakage current path without compromising the programming characteristic
Solution Approach 2:
The electrode structure is segmented into multiple functional layers: the copper wiring is separated from the variable resistance film by the barrier metal layer. This segmentation isolates the copper ions from the variable resistance film, preventing harmful diffusion while maintaining the desired programming functionality
2Object-generated harmful factors
If the barrier metal covers the side surface of the first electrode to prevent copper ion diffusion, then the leakage current is reduced, but the programming operation becomes unstable
Solution Approach 1:
The barrier metal layer is applied selectively to specific surfaces of the first electrode - covering the side surface and bottom surface to prevent copper ion diffusion, while leaving the upper surface exposed to enable proper contact with the variable resistance film and maintain stable programming operation
3Object-generated harmful factors
If the insulating film spacer is formed between the barrier metal and the variable resistance film to separate the electric field, then the leakage current is reduced, but the device complexity increases
Solution Approach 1:
An insulating film spacer is introduced as an intermediary element between the barrier metal and the variable resistance film. This spacer provides electric field separation that prevents leakage current while maintaining a relatively simple overall structure that can be integrated into existing semiconductor manufacturing 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
This configuration stabilizes the programming operation and reduces leakage current, allowing for efficient switching between high and low resistance states without increasing program voltage.
Implementation Method 1
a first electrode that is formed in an inside of the interlayer insulating film and includes an active electrode a side surface and a bottom surface of which are covered with a barrier metal
Implementation Method 2
an insulating film spacer that is formed between the barrier metal that covers a side surface of the first electrode and the variable resistance film
Implementation Method 3
NPL1 discloses a switching element using migration of metallic ions in an ion conductor and electrochemical reaction
Implementation Method 4
NPL1 discloses a switching element using migration of metallic ions in an ion conductor and electrochemical reaction
Data Source
AI summary
To stabilize programming operation and to reduce leakage current. A variable resistance element according to the present invention is provided with: an interlayer insulating film; a first electrode that is formed within the interlayer insulating film and comprises an active electrode, the side surface and the bottom surface of which are covered by a barrier metal; a variable resistance film that is formed on the upper surface of the first electrode; a second electrode that is formed on the variable resistance film; and an insulating film spacer that is formed between the variable resistance film and the barrier metal which covers the side surface of the first electrode. In this connection, the variable resistance film and the barrier metal which covers the side surface of the first electrode are in contact with the insulating film spacer, respectively.