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Plasma Polymerized HMDS for Magneto-optic Disk Corrosion Protection Overcoat

IP.com Disclosure Number: IPCOM000121896D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Eckhoff, H: AUTHOR [+6]

Abstract

Amorphous rare-earth transition metal (RE-TM) alloys have been found to be suitable for use as high density storage media because of their high coercivity at room temperature, high perpendicular anisotropy, and high Kerr rotation. However, the rare-earth element in the RE-TM alloy is extremely reactive. When the RE-TM films are exposed to ambient atmosphere, they are very susceptible to corrosion or oxidation which can cause degradation of magnetic properties, i.e., Kerr rotation, coercivity. To protect the RE-TM film from corrosion, "sandwich" structures are often used wherein the RE-TM film is deposited on a substrate and then overcoated with a layer of dielectric material. Usually, a layer of dielectric material is not sufficient for the corrosion protection due to pin holes.

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Plasma Polymerized HMDS for Magneto-optic Disk Corrosion Protection
Overcoat

      Amorphous rare-earth transition metal (RE-TM) alloys have
been found to be suitable for use as high density storage media
because of their high coercivity at room temperature, high
perpendicular anisotropy, and high Kerr rotation. However, the
rare-earth element in the RE-TM alloy is extremely reactive.  When
the RE-TM films are exposed to ambient atmosphere, they are very
susceptible to corrosion or oxidation which can cause degradation of
magnetic properties, i.e., Kerr rotation, coercivity.  To protect the
RE-TM film from corrosion, "sandwich" structures are often used
wherein the RE-TM film is deposited on a substrate and then
overcoated with a layer of dielectric material. Usually, a layer of
dielectric material is not sufficient for the corrosion protection
due to pin holes.  Another layer of metallic aluminum or an aluminum
alloy is usually deposited onto dielectric film as a barrier.
However, the metallic aluminum or aluminum alloys are also
susceptible to corrosion at high temperature and humidity.

      In this study, we have used plasma polymerized hexamethyl
disilazane (HMDS) as a protective overcoat for RE-TM films.  Plasma
polymerized HMDS overcoats provide greatly enhanced corrosion
resistance for RE-TM film structures.  The plasma polymerized HMDS
can either be directly deposited onto dielectric layer, to replace
metallic aluminum, or deposited onto the metallic...