Kobliska, Robert J.; Li, Eric K.;

Protective layer for magnetic disk

A magnetic recording disk composed of a substrate, a magnetic layer, and a protective/lubricative carbon layer is etched and has oxygen embedded into the surface of the disk. This carbon/oxygen surface is extremely smooth, and wears better than prior art disks not having oxygen imbedded in the surface. This altered layer enables a magnetic disk to undergo over twice the number of start/stop cycles without incurring damage from magnetic transducers used to read information from the recording than similar disks prepared without oxygen in the outer layer. A method of plasma etching is used to embed the oxygen into the surface.

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What is claimed is:

1. A method of increasing the lifetime of a magnetic disk recording device of the type having an outer carbon layer of elemental carbon over a magnetic recording layer, comprising the step of:

imbedding oxygen in the outer carbon layer until the atomic ratio in the outer 100 Angstroms of the carbon layer is in the range between 15% oxygen:85% carbon and 40% oxygen:60% carbon.

2. The method of claim 1 wherein the step of imbedding oxygen comprises:

loading the disk into an evacuated chamber; and

introducing a gas containing oxygen into the chamber; and

applying RF power inside the chamber to create a plasma and continuing the RF power until the atomic composition within the top 100 .ANG. of the carbon layer is between 15-40% oxygen and 85-60% carbon as measured by ESCA.

3. The method of claim 1 wherein the step of embedding oxygen into the carbon layer is continued until the carbon layer has an atomic composition of between 15-30% oxygen and 85-70% carbon, as measured by ESCA, in the top 100 .ANG. of the carbon layer.

4. A method as in claim 1 wherein the step of imbedding oxygen comprises:

loading the disk into an evacuated chamber;

introducing a gas continuing oxygen into the chamber; and

applying RF power inside the chamber to create a plasma and continuing the RF power until the atomic composition within the top 100 .ANG. of the carbon layer is between 15-30% oxygen and 85-60% carbon as measured by ESCA.

5. A method of increasing the lifetime of a magnetic disk recording device of the type having an outer carbon layer over a magnetic recording layer, comprising the step of:

etching the carbon layer using oxygen as an etchant gas to remove loosely bound carbon atoms, and continuing the etching until the atomic ratio in the outer 100 Angstroms of the carbon layer is in the range between 15% oxygen:85% carbon and 40% oxygen:60% carbon.

6. A magnetic recording disk comprising:

a substrate;

a magnetic layer over said substrate;

a carbon layer over said magnetic layer having an outer surface;

said carbon layer having an atomic composition of X% oxygen and 100-X% carbon within 100 .ANG. of the outer surface as measured by ESCA, where X is in the range of 15 to 40.

7. A magnetic disk as in claim 6 wherein X is in the range of 15 to 30.