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Fabrication of Biaxial Magnetic Films

IP.com Disclosure Number: IPCOM000090445D
Original Publication Date: 1969-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR

Abstract

Biaxial magnetic films are produced by this method on amorphous substrates, making it unnecessary to use single-crystal substrates for obtaining biaxial characteristics. Forming biaxial films on amorphous substrates greatly simplifies the production of such films. The substrate is formed by thermally growing an amorphous layer of oxide about 5,000 angstroms thick upon a silicon wafer. The magnetic film is vacuum-deposited upon the heated amorphous substrate to a thickness less than 1,000 angstroms. The source material consists of permalloy having standard 83/17 proportions of nickel and iron, doped with 7 percent of cobalt. A slug of this material is heated in an electron beam gun with input power of approximately 1,000 watts. The evaporation rate is typically 5 angstroms per second in a vacuum of from 1 to 2 x 10/-6/ Torr.

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Fabrication of Biaxial Magnetic Films

Biaxial magnetic films are produced by this method on amorphous substrates, making it unnecessary to use single-crystal substrates for obtaining biaxial characteristics. Forming biaxial films on amorphous substrates greatly simplifies the production of such films. The substrate is formed by thermally growing an amorphous layer of oxide about 5,000 angstroms thick upon a silicon wafer. The magnetic film is vacuum-deposited upon the heated amorphous substrate to a thickness less than 1,000 angstroms. The source material consists of permalloy having standard 83/17 proportions of nickel and iron, doped with 7 percent of cobalt. A slug of this material is heated in an electron beam gun with input power of approximately 1,000 watts. The evaporation rate is typically 5 angstroms per second in a vacuum of from 1 to 2 x 10/-6/ Torr. Substrate temperature is maintained at 450 degrees C or higher during evaporation. The film is deposited in a magnetic field of 70 oersteds applied along a desired easy- axis direction in the plane of the substrate. The resultant magnetic film exhibits biaxial anisotropy along both the field-induced easy axis and an axis at right angles to it, the hysteresis loops for these two axes being substantially identical. Cobalt doping enables permalloy to be used for making biaxial films according to this method without requiring single-crystal substrates.

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