RRAM Contact Member Tip Geometry for Mask Reduction
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Solution Overview
Problem
Existing methods for integrating resistive random-access memory (RRAM) cells into semiconductor devices require multiple etching masks, complicating the manufacturing process.
Innovation Solution
A memory cell design where the contact member serves as both an electrical connection between the front-end-of-line (FEOL) and back-end-of-line (BEOL) metal, and as the bottom electrode of the memristor, reducing the number of etching masks needed by performing dual roles, and featuring a recessed end surface that forms a tip to enhance the electric field focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate bottom electrode and contact member are used, then electrical connection is achieved, but device complexity increases due to multiple etching masks
Solution Approach 1:
The patent combines the bottom electrode and contact member into a single integrated structure. The contact member extends from the substrate through the dielectric layer and serves dual functions: providing electrical connection between FEOL and BEOL metal layers, and acting as the bottom electrode for the RRAM cell. This integration eliminates the need for separate bottom electrode formation and reduces the number of etching masks required during manufacturing.
Solution Approach 2:
The contact member is designed to perform multiple functions simultaneously: (1) electrical connection between front-end-of-line and back-end-of-line metal layers, (2) serving as the bottom electrode for the memristor switching layer, and (3) providing structural support. This multi-functionality reduces device complexity while maintaining all necessary electrical connections and memory cell functionality.
2Ease of manufacture
If flat contact member end surface is used, then manufacturing is simple, but electric field focus is insufficient
Solution Approach 1:
The contact member features a non-uniform geometry with a recessed end surface that creates a localized tip region. This local quality change concentrates the electric field at the tip where it is most needed for memristor operation, while the rest of the contact member maintains a simpler structure for ease of manufacture. The tip geometry can be formed by controlled etching processes that create the recessed profile.
Solution Approach 2:
The recessed end surface of the contact member creates a curved or rounded tip geometry rather than a flat surface. This curvature concentrates the electric field lines at the tip region, enhancing the electric field focus needed for reliable memristor switching. The curved profile can be achieved through standard semiconductor fabrication techniques such as anisotropic etching or reactive ion etching.
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 design simplifies the manufacturing process by reducing the number of etching masks required and enhances the electric field focus, improving the efficiency and scalability of RRAM integration.
Implementation Method 1
The second end may have a recessed end surface that has a section that slopes towards the side surface so as to form a tip with the side surface at the second end
Data Source
AI summary
According to various embodiments, there is provided a memory cell. The memory cell may include a transistor, a dielectric member, an electrode and a contact member. The dielectric member may be disposed over the transistor. The electrode may be disposed over the dielectric member. The contact member has a first end and a second end opposite to the first end. The first end is disposed towards the transistor, and the second end is disposed towards the dielectric member. The contact member has a side surface extending from the first end to the second end. The second end may have a recessed end surface that has a section that slopes towards the side surface so as to form a tip with the side surface at the second end. The dielectric member may be disposed over the second end of the contact member and may include at least a portion disposed over the tip.