TiON Overcoat for HAMR Head Thermal Stability
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Solution Overview
Problem
High operating temperatures in heat-assisted magnetic recording heads lead to structural and chemical damage due to oxidation, corrosion, and vapor exposure, affecting the performance and durability of the recording medium.
Innovation Solution
A titanium oxynitride layer is applied as an overcoat on the air-bearing surface of the magnetic recording head to act as a gas barrier, providing thermal stability and protection against chemical degradation while maintaining optical transmissivity and refractive index suitable for heat-assisted magnetic recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional overcoat material is used to protect the magnetic recording head, then mechanical protection is provided, but thermal stability and resistance to chemical degradation at high temperatures are insufficient
Solution Approach 1:
The patent applies a composite overcoat structure consisting of multiple layers including titanium oxynitride (TiON), silicon nitride (Si3N4), and diamond-like carbon (DLC). This composite structure combines the chemical inertness and thermal stability of TiON and Si3N4 with the mechanical protection of DLC, resolving the contradiction between chemical resistance and mechanical protection at high operating temperatures.
Solution Approach 2:
The patent changes the material composition parameters of the overcoat by incorporating specific ratios of titanium, oxygen, and nitrogen to form TiON compounds with optimized properties. This parameter change enables the overcoat to maintain structural integrity and resist chemical degradation at temperatures exceeding 200-300°C, directly addressing the thermal stability deficiency of conventional materials.
2Reliability
If the overcoat is made thicker to improve protection, then durability increases, but optical transmissivity decreases affecting heat-assisted magnetic recording performance
Solution Approach 1:
The patent applies different materials with different properties to different layers of the overcoat structure. The TiON and Si3N4 layers provide chemical and thermal protection, while the DLC layer provides mechanical protection. Each layer is optimized for its specific function, allowing the overall structure to be sufficiently thin for optical transmissivity while maintaining durability through the combined protective properties of all layers.
3Object-affected harmful factors
If standard protective coatings are applied, then mechanical damage protection is achieved, but protection against vapor-induced chemical damage at high temperatures is insufficient
Solution Approach 1:
The titanium oxynitride and silicon nitride layers create an inert barrier between the reactive vapor environment and the underlying magnetic recording head structures. These materials are chemically inert at operating temperatures and prevent oxygen and water vapor from reaching and degrading the write pole and near field transducer, effectively creating a protective inert environment.
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 titanium oxynitride overcoat enhances thermal gradient and areal density, improving the durability and performance of the magnetic recording head by reducing structural damage and maintaining data quality, with a 5-20% increase in thermal gradient and 10-70% improvement in overcoat lifetime compared to control overcoats.
Implementation Method 1
an overcoat layer that acts as a gas barrier may be placed over an otherwise exposed surface of the device
Implementation Method 2
The near field transducer absorbs the radiation and transfers and focuses the energy to a very small area of the recording medium
Implementation Method 3
transfers and focuses the energy to a very small area of the recording medium
Implementation Method 4
The titanium oxynitride overcoat enhances thermal gradient and areal density, improving the durability and performance of the magnetic recording head
Data Source
AI summary
Described are magnetic recording heads that include an overcoat that includes a titanium oxynitride (TiON) layer.