Faceted Sidewall MTJ Structure for Embedded MRAM
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of embedded high performance magnetoresistive random access memory (MRAM) devices with perpendicular magnetic tunnel junction (MTJ) structures is hindered by the risk of shorts due to re-sputtering of metal ions during reactive ion etch and ion beam etch processing, which damages the MTJ stack sidewalls.
Innovation Solution
A method is developed to form a magnetic tunnel junction (MTJ) structure with faceted sidewalls on a conductive landing pad embedded in a dielectric material layer, where no metal ions are re-sputtered onto the sidewalls, reducing the risk of shorts by using a patterned dielectric capping layer with tapered sidewalls and carefully controlling the deposition and patterning of MTJ layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reactive ion etch or ion beam etch processing is used to pattern MTJ stacks, then high performance embedded MRAM devices can be formed, but metal ions are re-sputtered onto the MTJ stack sidewalls causing shorts
Solution Approach 1:
A protective coating is deposited on the MTJ stack sidewalls before the etching process. This preliminary protective layer prevents metal ion re-sputtering during subsequent reactive ion etch or ion beam etch processing, eliminating the shorting problem while allowing high-performance embedded MRAM device formation
Solution Approach 2:
The protective coating acts as an intermediary layer between the etching plasma and the MTJ stack sidewalls. It mediates the interaction by absorbing or deflecting metal ions during etching, preventing direct contamination of the MTJ structure and enabling reliable device formation
2Ease of manufacture
If conventional patterning methods are used on blanket MTJ stacks, then manufacturing process is simplified, but metal re-sputtering damages the MTJ stack sidewalls
Solution Approach 1:
The protective coating is applied to the MTJ stack sidewalls before patterning operations. This preliminary protection allows conventional patterning methods to be used while preventing metal re-sputtering damage, thus maintaining both manufacturing simplicity and sidewall integrity
Solution Approach 2:
The protective coating serves as an intermediary that shields the MTJ stack sidewalls during conventional patterning processes. It enables the use of simple, established manufacturing techniques while preventing damage to the delicate sidewall structures
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 effectively prevents metal re-sputtering onto the MTJ structure sidewalls, thereby reducing the risk of shorts and ensuring the integrity of the MTJ structure, enabling the formation of high-performance embedded MRAM devices with reduced defects.
Implementation Method 1
Reactive ion etch (RIE) processing and ion beam etch (IBE) processing of such MTJ stacks presents a major challenge, as such processing typically leads to shorts due to re-sputtering of thick bottom metal layers onto the MTJ stack sidewalls
Data Source
AI summary
A magnetic tunnel junction (MTJ) structure having faceted sidewalls is formed on a conductive landing pad that is present on a surface of an electrically conductive structure embedded in a dielectric material layer. No metal ions are re-sputtered onto the sidewalls of the MTJ structure during the patterning of the MTJ material stack that provides the MTJ structure. The absence of re-sputtered metal on the MTJ structure sidewalls reduces the risk of shorts.