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Self-Aligned Two-Step Process for Flux Enhancement in Magnetoresistive Sensors

IP.com Disclosure Number: IPCOM000047536D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Beam, DL: AUTHOR [+2]

Abstract

A magnetic yoke for enhancing the performance of a magnetoresistive sensor is formed by a low temperature deposition process to minimize Barkenhausen noise. By an appropriate sequence of mask etching, components of the yoke structure and the magnetoresistive element are formed with great precision. - A thick (e.g., 3,000 ) layer 10 of nickel-iron alloy is first vacuum-deposited onto substrate 11 while the substrate is maintained at about 100ŒC. - Through the use of an appropriate mask, an opening 12 is formed in the layer 10 by sputter etching. - A thin (350 ) nickel-iron layer 13 is vacuum-deposited over the entire surface while maintaining the substrate 11 at about 250ŒC and while applying a magnetic field of about 60 0e along axis 12 to set the easy axis of the magnetoresistive element.

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Self-Aligned Two-Step Process for Flux Enhancement in Magnetoresistive Sensors

A magnetic yoke for enhancing the performance of a magnetoresistive sensor is formed by a low temperature deposition process to minimize Barkenhausen noise. By an appropriate sequence of mask etching, components of the yoke structure and the magnetoresistive element are formed with great precision. - A thick (e.g., 3,000 ) layer 10 of nickel-iron alloy is first vacuum-deposited onto substrate 11 while the substrate is maintained at about 100OEC. - Through the use of an appropriate mask, an opening 12 is formed in the layer 10 by sputter etching. - A thin (350 ) nickel-iron layer 13 is vacuum-deposited over the entire surface while maintaining the substrate 11 at about 250OEC and while applying a magnetic field of about 60 0e along axis 12 to set the easy axis of the magnetoresistive element. - A further mask is applied to the outer surface to define gaps, such as 14, 15 and 16, which are formed by sputter etching through layers 13 and 10. Through the use of a single mask to form these gaps, the magnetic components, such as magnetoresistive element 17, flux extenders 18 and 19, are automatically aligned. The gaps thus are not required to be enlarged so as to accommodate potential misalignment. - Finally, a layer of gold 20 is deposited to provide electrical contact, and a layer of Al2O3 is deposited to provide passivation.

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