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Fabrication of Fe(3)O(4) Films by Phase Transformation of Sputtered Fe(2)O(3) Films

IP.com Disclosure Number: IPCOM000083633D
Original Publication Date: 1975-Jun-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Bajorek, CH: AUTHOR

Abstract

In order to provide Fe(3)O(4) (magnetite) films whose surfaces are quite smooth, the following steps are suggested:

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Fabrication of Fe(3)O(4) Films by Phase Transformation of Sputtered Fe(2)O(3) Films

In order to provide Fe(3)O(4) (magnetite) films whose surfaces are quite smooth, the following steps are suggested:

1. Reactively sputter Fe in an oxygen atmosphere to form Fe(2)O(3) films by known techniques. The formation of sputtered Fe(2)O(3) films requires negligible control of O(2) pressure in the sputtering system. Equally good Fe(2)O(3) films could also be prepared by reactive evaporation of Fe. This direct fabrication of Fe(2)O(3) films, as opposed to thermal techniques, gives rise to the ultimate smooth films.

2. Overcoat Fe(2)O(3) film with a layer of evaporated or sputtered iron. This supplies the Fe necessary to allow Fe(2)O(3) to convert to Fe(3(O(4) since Fe(3)O(4) has 12% more Fe than Fe(2)O(3) (for fixed oxygen content). This step also supplies excess Fe which serves as a protective layer in step 4 below.

3. Anneal composite film structure in oxygen deficient atmosphere (vacuum 10/-6/ torr) at a temperature of approximately 360 degrees C for several minutes. This step recognizes the fact that Fe is in equilibrium with Fe(3)O(4) in an oxygen deficient atmosphere below 600 degrees C (see book entitled "Constitution of Binary Alloys", by M. Hansen, McGraw Hill, 1958, p. 684). The vacuum of 10/-6/ torr protects Fe film from oxidation.

4. Remove excess Fe without removing oxide (dilute HNO(3) or 1 part Br-5 parts ethyl acetate solution) and obtain pure Fe(3)O(4) film....