Ovonic Threshold Selector Interface for Peeling-Resistant Memory Cells
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Solution Overview
Problem
The challenge in semiconductor manufacturing lies in the peeling and contact failure between selector layers and electrodes in non-volatile memory devices, particularly in resistive random-access memories, which affects yield and stability.
Innovation Solution
Incorporating an intermediate layer between the selector and electrode layers, acting as a glue or barrier layer, with the selector layer having a larger top area to provide a stable base, and using specific materials and deposition methods to enhance adhesion and prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intermediate layer is added between the selector and electrode layers, then adhesion and stability are improved, but device complexity increases
Solution Approach 1:
An intermediate layer is introduced between the selector layer and the electrode layer to serve as a mediator that improves adhesion and prevents peeling. This intermediate layer acts as a buffer zone that resolves the interface compatibility issues between the selector layer and electrode, thereby enhancing overall device reliability without requiring fundamental changes to the existing structure.
2Reliability
If the selector layer is designed with a larger top area, then contact stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The selector layer is designed with an asymmetric area distribution, where the top area is intentionally made larger than the bottom area. This asymmetric geometry provides a larger contact area with the electrode, improving contact stability and reducing the risk of peeling. The specific area ratio (top area larger than bottom area) creates a mechanical advantage that enhances adhesion while remaining compatible with standard manufacturing processes.
Data Source
AI summary
A method of forming a memory cell and a method of forming a selector are provided. The method of forming the memory cell includes forming a selector over a substrate, including: forming a bottom electrode; forming an ovonic threshold switch layer on the bottom electrode; forming an inter-electrode over the ovonic threshold switch layer; forming an intermediate layer between the ovonic threshold switch layer and the inter-electrode; and forming a memory element on the selector; and forming a connecting pad on the memory element. The intermediate layer has a curved sidewall extending from a top surface of the ovonic threshold switch layer to a bottom surface of the inter-electrode.