Structure of nitrogenated carbon overcoats on thin-film hard disks

Huang, L. J.; Hung, Yu-Chueh; Chang, S.

doi:10.1109/20.649893

Cited by 15 publications

(6 citation statements)

References 20 publications

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“…Several studies on carbon nitride layers showed, however, that the low m/z clusters carry highly relevant structural information. Huang et al (1997a;1997b) showed that TOF S-SIMS allowed characterization of carbon nitride overcoats on thin-®lm hard disks. The surface was sputter cleaned with the Ga beam.…”

Section: Elemental Analysis and Inorganic Speciationmentioning

confidence: 99%

Static secondary ion mass spectrometry (S-SIMS) Part 1: methodology and structural interpretation

Vaeck

Adriaens

Gijbels

1999

Mass Spectrom. Rev.

184

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Section: Elemental Analysis and Inorganic Speciationmentioning

confidence: 99%

Static secondary ion mass spectrometry (S-SIMS) Part 1: methodology and structural interpretation

Vaeck

Adriaens

Gijbels

1999

Mass Spectrom. Rev.

184

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“…Recently, a number of manufacturers of magnetic recording media have replaced the CHx overcoat with an amorphous-nitrogenated carbon (CNx) overcoat. Reports extolling the tribological benefits of CNx have appearedl − Most have attributed the apparent improvement in the tribology of CNx overcoats relative to CHx overcoats to the increased hardness of the CNx film. However, altering the nature of the carbon surface could also strongly influence the PFPE lubricant via modifying the adhesive strength, bonding kinetics, lubricant orientation, and/or lubricant mobility.…”

Section: Introductionmentioning

confidence: 99%

Concerning the Interactions between Zdol Perfluoropolyether Lubricant and an Amorphous-Nitrogenated Carbon Surface

1998

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The interactions that occur between the hydroxyl-terminated perfluoropolyethers Zdol 2000/4000 and an amorphous-nitrogenated carbon surface (CNx) were studied via surface energy measurements, kinetic measurements, and ab initio calculations. The results of these measurements are compared with those of previous studies on the Zdol/amorphous-hydrogenated carbon (CHx) system and the major differences identified. The thickness dependence of the dispersive surface energy for the Zdol/CNx system can be fit using a repulsive van der Waals potential. Effective Hamaker constants determined for both the Zdol/CNx and Zdol/CHx systems demonstrate that Zdol is less effective at covering CNx as compared to CHx due to less favorable interactions between the Zdol backbone and the CNx surface. The Zdol thickness dependence of the polar surface energy for the Zdol/CNx system indicates that very few strong polar interactions are present between the initially applied Zdol and the CNx surface. A substantial decrease in the polar surface energy of the first Zdol monolayer however occurs on a time scale of 1-5 weeks after lubricant application. The attractive well that develops in the free energy versus thickness curve reflects the formation of attractive interactions between the polar hydroxyl end groups of Zdol and the polar entities on the CNx surface. A kinetic analysis of the Zdol + CNx system reveals that the rate at which the adhesive interactions are formed is limited by diffusion of the polar end groups to the surface active sites. Ab initio calculations indicate that attractive hydrogen-bonding interactions between the hydroxyl end groups of Zdol and imine (basic) sites on the CNx surface may be responsible for the Zdol adhesion. These calculations further suggest that the appearance of the diffusion step in the bonding kinetics and the less efficient coverage of Zdol on CNx are manifestations of repulsive interactions that exist between the basic imine surface sites and the basic perfluorinated Zdol backbone.

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“…Because of the small number of gas-phase events, removed particles from the substrate are unlikely to be redeposited on it. 23 The surface roughness data obtained by the scanning probe microscope indicated a smoother film development with increasing H atom % content in the Ar ϩ N 2 ϩ C 2 H 4 gas mixture. Redeposition of these particles is much lower at small deposition pressures.…”

Section: Resultsmentioning

confidence: 94%

Influence of Carbon Sputtering Conditions on Corrosion Protection of Magnetic Layer by an Electrochemical Technique

Balakrisnan¹,

Tomčik

Blackwood³

2002

J. Electrochem. Soc.

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For high density magnetic recording, it is necessary to protect the magnetic layer from wear and corrosion with a thin carbon overcoat. On ultrasmooth disk substrates, magnetron sputtering is still the preferred technique because it can provide protective carbon layers as thin as 4 nm. Degradation of the magnetic layer occurs in the atmosphere and during hard disk operation; thus, the carbon-based overcoat functions as an indispensable component in protecting the essential magnetic layer. Moreover, carbon overcoat quality plays a vital role in the strong demand to reduce the flying height between a disk and read/write head, which in turn enhances the density of recording. The impact of sputtering conditions on the quality of deposited amorphous hydrogenated and nitrogenated carbon was assessed by the electrochemical measurement of the linear polarization resistance. The film's polarization resistance was correlated to its porosity, and a statistical method was developed to allow easy comparison of results in the data analysis. The results obtained suggest that the best overcoats are formed with a substrate voltage bias of Ϫ120 V, a very low deposition pressure of 0.9 mTorr, a dc magnetron sputtering power of 2.8 W/cm 2 , and with incorporation of ethylene gas in the Ar ϩ N 2 gas mixture. The filling of film voids increased with ion flux and decreased with increasing deposition rate.

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Structure of nitrogenated carbon overcoats on thin-film hard disks

Cited by 15 publications

References 20 publications

Static secondary ion mass spectrometry (S-SIMS) Part 1: methodology and structural interpretation

Static secondary ion mass spectrometry (S-SIMS) Part 1: methodology and structural interpretation

Concerning the Interactions between Zdol Perfluoropolyether Lubricant and an Amorphous-Nitrogenated Carbon Surface

Influence of Carbon Sputtering Conditions on Corrosion Protection of Magnetic Layer by an Electrochemical Technique

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