Browse Prior Art Database

Fabrication of Discrete Patterns in Garnet Films

IP.com Disclosure Number: IPCOM000079572D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Brown, JA: AUTHOR [+3]

Abstract

Described is a process for producing discrete patterns in garnet films fabricated by a wet-chemical method. /1/ Such patterns may be used as storage elements in beam-addressable memories, or as guide rails in bubble memories with lateral displacement coding. The described process solves the problem of selectively etching the desired patterns but not the underlying substrate or bubble material, which may have similar chemical properties. This is achieved by etching the spun garnet film in its amorphous state, and subsequently transforming the unetched areas into crystalline garnet by suitable heat treatment.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Fabrication of Discrete Patterns in Garnet Films

Described is a process for producing discrete patterns in garnet films fabricated by a wet-chemical method. /1/ Such patterns may be used as storage elements in beam-addressable memories, or as guide rails in bubble memories with lateral displacement coding. The described process solves the problem of selectively etching the desired patterns but not the underlying substrate or bubble material, which may have similar chemical properties. This is achieved by etching the spun garnet film in its amorphous state, and subsequently transforming the unetched areas into crystalline garnet by suitable heat treatment.

For example, a five-coat thickness of GdIG material is deposited on a high- temperature glass or yttrium aluminum garnet (YAG) substrate. The film is not fired to the crystalline garnet phase but is kept in the amorphous, dried film condition. Patterns are produced in films of this type by conventional photoetching techniques, using either FeCl(3) etchant or dilute HCl. These etchants were tested for their effect on the substrate material. There was no attack in the period of time required for etching the amorphous film. Thus geometric patterns in the spun garnet material are produced. 1 E. A. Giess and
R. M. Potemski, "Rare Earth Garnet Film Fabrication," IBM Technical Disclosure Bulletin, Vol. 9, No. 8, Page 960, January 1967.

1