MgO Barrier Formation via DC Sputtering and Annealing
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Solution Overview
Problem
Existing methods for forming metal oxide barrier layers in data storage devices face challenges such as plasma damage from RF deposition and ensuring stoichiometry in natural oxidation processes, which affect the resistance-area product (RA) and tunnel magnetoresistance (TMR) ratios.
Innovation Solution
A method involving the application of oxidation to a reference layer and depositing multiple magnesium layers at different temperatures with varying oxidation doses, followed by an annealing process to form a stoichiometric magnesium oxide barrier layer, using a DC sputtering method to ensure high TMR at low RA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF deposition is used to form metal oxide barrier layers, then deposition efficiency is improved, but plasma damage occurs affecting RA and TMR ratios
Solution Approach 1:
The patent replaces RF deposition (plasma-based process) with DC sputtering (physical vapor deposition). This substitution eliminates plasma damage to the barrier layer while maintaining efficient deposition capability, directly resolving the contradiction between deposition efficiency and plasma damage avoidance
Solution Approach 2:
The patent employs an inert atmosphere environment during DC sputtering deposition to prevent unwanted chemical reactions and plasma-related damage. The inert environment protects the forming metal oxide barrier layer from plasma damage while allowing controlled oxidation to achieve stoichiometric composition
2Manufacturing precision
If natural oxidation is used to form metal oxide barrier layers, then stoichiometry is improved, but the process time increases and RA control is affected
Solution Approach 1:
The patent applies a preliminary oxidation treatment to the reference layer before depositing magnesium layers. This preliminary action creates an oxygen-terminated surface that facilitates controlled oxidation during subsequent DC sputtering, reducing the time needed to achieve stoichiometric MgO while maintaining precise RA control
Solution Approach 2:
The patent changes oxidation parameters by applying controlled oxidation doses at different temperatures to different magnesium layers during the DC sputtering process. This parameter control accelerates the oxidation process compared to natural oxidation, reducing process time while maintaining stoichiometric composition and precise RA 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 effectively reduces RA without compromising TMR, achieving a better stoichiometric and crystallized MgO barrier layer that enhances the performance of magnetic tunnel junctions.
Implementation Method 1
using a DC sputtering method to ensure high TMR at low RA
Implementation Method 2
applying oxidation to a top of a reference layer, and depositing a plurality of different magnesium layers over the reference layer
Implementation Method 3
performing an annealing operation after depositing at least two of the plurality of different magnesium layers
Data Source
AI summary
A multi-layer barrier and method of formation. The method includes applying oxidation to a top of a reference layer, and depositing a plurality of different metal layers over the reference layer. The method also includes providing different oxidation doses at different temperatures to different layers of the plurality of metal layers. The method further includes performing an annealing operation after depositing at least two of the plurality of different metal layers.