Template-Layer Near Field Transducer for Rh Peg Reliability
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Solution Overview
Problem
The reliability of thermally-assisted magnetic recording (TAMR) heads is compromised due to the instability of Rh pegs in the near field transducer (NFT) structure, which experience grain growth and recrystallization at high temperatures, leading to unreliable data recording.
Innovation Solution
A near field transducer (NFT) structure is fabricated using a template layer to stabilize the Rh pegs, ensuring they maintain a desired (111) crystalline orientation, followed by a selective wet etch process to remove the template and fill with dielectric material, enhancing the structural integrity and reliability of the NFT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Rh pegs are used in the NFT structure to concentrate plasmon energy, then the heating efficiency and recording capability are improved, but the reliability deteriorates due to grain growth and recrystallization at high temperatures
Solution Approach 1:
A template layer is deposited beforehand on the waveguide core before depositing the Rh layer. This template layer serves as a substrate that pre-establishes the desired (111) crystalline orientation for the Rh pegs, preventing grain growth and recrystallization during high-temperature operation. The template layer is removed after serving its stabilizing function, leaving behind reliable Rh pegs with maintained crystalline structure.
Solution Approach 2:
The template layer acts as an intermediary substance that facilitates the formation of stable Rh pegs with desired crystalline orientation. It mediates between the waveguide core and the Rh layer, providing a controlled interface that ensures proper crystal growth. The template layer is subsequently removed, having fulfilled its mediating role in establishing reliable Rh peg structure.
2Manufacturing precision
If the magnetic recording areal density is increased by reducing grain size, then the area density capability is improved, but the storage lifetime deteriorates due to reduced media thermal stability
Solution Approach 1:
The invention changes the crystalline orientation parameter of the Rh pegs to (111) through the use of a template layer. This parameter change enhances the thermal stability of the Rh pegs, allowing them to maintain their structural integrity at high temperatures during operation. The improved thermal stability directly addresses the storage lifetime issue while maintaining the small grain size needed for high areal density.
3Reliability
If a template layer is added to stabilize Rh pegs, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The template layer is discarded after serving its purpose of stabilizing Rh peg crystalline orientation. It is removed through selective wet etching after the Rh pegs have been formed and stabilized. This approach allows the template layer to be used temporarily during fabrication to ensure reliability, then discarded to avoid adding permanent complexity to the final device structure.
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
The method improves the reliability of the NFT by maintaining large, stable Rh peg grains, reducing failure rates and achieving the desired crystalline orientation, thus enhancing the performance and durability of TAMR heads.
Implementation Method 1
The waveguide propagated electromagnetic radiation is transferred, by electromagnetic coupling, to a plasmon generator (PG) adjacent to (above or below) the waveguide at the distal end of the waveguide
Implementation Method 2
The optical radiation coupled by the waveguide to the plasmon generator is in turn coupled to the recording medium via plasmon near-field energy, and, thus, heats the surface of recording media
Implementation Method 3
A near field transducer (NFT) structure is fabricated using a template layer to stabilize the Rh pegs, ensuring they maintain a desired (111) crystalline orientation
Data Source
AI summary
A method of fabricating a near field transducer (NFT) in a thermally assisted magnetic recording (TAMR) head is disclosed. In some embodiments, the method includes: depositing a dielectric layer and a template layer on a waveguide core; patterning the template layer to form a template; depositing an Au NFT layer; planarizing the Au NFT layer to generate a planar layer; depositing an upper NFT layer; applying a peg patterning mask; etching the upper NFT layer and the planar layer that includes the Au NFT layer; removing the template; and depositing a dielectric material and planarizing an upper surface that includes the upper NFT layer.