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Use of Silicon Dioxide (SiO2) as an Insulating Layer on Ferrite Materials

IP.com Disclosure Number: IPCOM000110221D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Related People

Stern, GC: AUTHOR [+2]

Abstract

In creating a film of alumina on a magnetic head substrate of NiZn ferrite, for instance, uniform etching of the alumina film is crucial. By precoating the ferrite with a layer of SiO2 there is improved control in this etching process.

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Use of Silicon Dioxide (SiO2) as an Insulating Layer on Ferrite Materials

      In creating a film of alumina on a magnetic head substrate of
NiZn ferrite, for instance, uniform etching of the alumina film is
crucial.  By precoating the ferrite with a layer of SiO2 there is
improved control in this etching process.

      The base layer of silicon dioxide creates an alumina which has
more uniform properties.  In some cases a polycrystalline phase can
propagate from the spinal structure of the ferrite into the alumina.
This phase material is very difficult to etch.  This crystalline
phase has not been seen on ferrites which were coated with silicon
dioxide prior to alumina deposition.

      The etchability of alumina is a characteristic based on the
processing conditions.  To avoid non-uniform alumina etch in
post-sputtering processes, there may be a requirement for very high
vacuum (less than 2 x 10-7 Torr) to purge the sputtering system of
water vapor and background gases.  The use of silicon dioxide as an
underlayer has been found to eliminate the requirements for the long
vacuum pump times.  Because of the thickness of the silicon dioxide
there is an improvement in the detection of the end point of the etch
on the transparent alumina.

      By undercoating the alumina film with a 1000 Ao + 200 Ao film
of silicon dioxide, the total time for alumina deposition can be
reduced and the etchability of the film is improved.  The process can
be adopted t...