Capped Magnetic Memory MTJ Electrode Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Spin-transfer torque magnetic random access memory (STTM) devices face stability issues and electrical shorting problems during aggressive scaling, particularly due to non-volatile byproducts from etching processes that can cause electrical shorting between electrodes, and the poor selectivity of etching processes that damage top electrodes.
Innovation Solution
A protective film is formed over the top electrode, followed by a highly selective capping layer that protects the top electrode during the etching of the bottom electrode, preventing redeposition of electrode byproducts onto the top electrode and maintaining the integrity of the MTJ stack, thereby avoiding electrical shorting and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If etching processes are used to fabricate MTJ devices, then device density and scaling are improved, but non-volatile byproducts cause electrical shorting between electrodes and etching damage occurs to top electrodes
Solution Approach 1:
A capping layer is introduced as an intermediary protective element between the etching process and the top electrode. This capping layer selectively protects the top electrode from etching damage and prevents non-volatile byproducts from causing electrical shorting, while allowing the etching process to continue for fabricating bottom electrodes and improving device density
Solution Approach 2:
The capping layer is formed on the top electrode before the etching process begins. This preliminary protective action prevents damage to the top electrode and prevents byproduct redeposition during subsequent etching steps, maintaining electrode integrity while enabling aggressive scaling
2Length of moving object
If etching processes are used to remove bottom electrodes, then device scaling is improved, but poor etching selectivity damages top electrodes
Solution Approach 1:
The capping layer serves as a protective intermediary that enables selective etching. It allows the etching process to remove bottom electrodes while preventing damage to the top electrode, achieving the required manufacturing precision for electrode integrity during scaling
Solution Approach 2:
The capping layer provides localized protection specifically to the top electrode region. This local quality enhancement allows different parts of the device to experience different etching conditions - the bottom electrode is etched away while the top electrode remains protected, enabling precise feature size control
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 approach prevents electrical shorting and improves the stability of MTJ devices, allowing for more aggressive scaling while maintaining power efficiency and reliability, enabling the fabrication of stable and scalable memory cells.
Implementation Method 1
a highly selective capping layer that protects the top electrode during the etching of the bottom electrode, preventing redeposition of electrode byproducts onto the top electrode
Implementation Method 2
etching processes that damage top electrodes
Data Source
AI summary
An embodiment includes an apparatus comprising: a magnetic tunnel junction (MTJ), between first and second electrodes, comprising a dielectric layer between fixed and free layers; a dielectric film directly contacting sidewalls of the first electrode; and a metallic layer coupled to the sidewalls via the dielectric film; wherein (a) a vertical axis intersects the first and second electrodes and the MTJ but not the metallic layer, (b) a first horizontal axis intersects the metallic layer, the dielectric film, and the first electrode; and (c) a second horizontal axis, between the first horizontal axis and the MTJ, intersects the dielectric film and the first electrode but not the capping layer. Other embodiments are described herein.