Adhesion Layer Design for HAMR Near Field Transducer Peg Stability
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Solution Overview
Problem
Heat-assisted magnetic recording (HAMR) near field transducers (NFTs) face material diffusion and deformation issues due to low adhesion strengths between the peg and surrounding surfaces at high operating temperatures, leading to potential failure of the NFT and the entire head.
Innovation Solution
Incorporating adhesion layers with materials such as rhenium, osmium, iridium, platinum, and their combinations on the air bearing surface of the NFT peg to enhance adhesion, utilizing metals, oxides, nitrides, and carbides with high surface energies and low interface energies to improve material bonding and reduce diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat-assisted magnetic recording (HAMR) near field transducers (NFTs) operate at high temperatures, then recording performance is improved, but material diffusion and deformation occur due to low adhesion strengths
Solution Approach 1:
An adhesion layer comprising titanium (Ti), tungsten (W), molybdenum (Mo), chromium (Cr), silicon (Si), nickel (Ni), tantalum (Ta), titanium nitride (TiN), zirconium nitride (ZrN), or hafnium nitride (HfN) is introduced between the peg material and the surrounding surfaces. This intermediary layer provides strong bonding interfaces that prevent material diffusion and deformation even when the NFT operates at elevated temperatures, thereby resolving the contradiction between high-temperature operation and adhesion strength
Solution Approach 2:
The NFT structure is designed as a composite system with distinct material layers: a peg made of gold (Au), silver (Ag), copper (Cu), aluminum (Al), rhodium (Rh), rhenium (Re), or their alloys, combined with a specially selected adhesion layer. This composite structure leverages the unique properties of each material - the peg material provides the necessary optical and electrical properties for NFT function, while the adhesion layer provides thermal stability and strong bonding, thus resolving the contradiction between operating temperature and adhesion strength
2Reliability
If adhesion layers are added to the NFT peg, then adhesion strength is improved, but device complexity increases
Solution Approach 1:
The adhesion layer is applied locally only to the peg structure where it is most needed for preventing material diffusion and deformation, rather than coating the entire NFT. This localized application maintains adhesion strength improvements while minimizing the increase in overall device complexity
Solution Approach 2:
The adhesion layer is deposited on the peg structure before the final NFT assembly is completed. This preliminary action ensures proper adhesion from the outset, preventing future failures without requiring complex post-processing or additional structural elements, thus improving reliability with minimal complexity increase
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 adhesion layers effectively increase the adhesion strength between the NFT material and surrounding surfaces, reducing the likelihood of peg deformation and recess, thereby enhancing the reliability and longevity of the NFT during high-temperature operations.
Implementation Method 1
the adhesion layer effectively increase the adhesion strength between the NFT material and surrounding surfaces
Implementation Method 2
reducing the likelihood of peg deformation and recess, thereby enhancing the reliability and longevity of the NFT during high-temperature operations
Data Source
AI summary
A device that includes a near field transducer (NFT), the NFT having a disc and a peg, and the peg having an air bearing surface thereof; and at least one adhesion layer positioned on at least the air bearing surface of the peg, the adhesion layer including one or more of platinum (Pt), iridium (Ir), ruthenium (Ru), rhodium (Rh), palladium (Pd), yttrium (Y), chromium (Cr), nickel (Ni), and scandium (Sc).