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Growth of Very Thin Magnetic Garnet Thin Films

IP.com Disclosure Number: IPCOM000050431D
Original Publication Date: 1982-Oct-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gangulee, A: AUTHOR [+3]

Abstract

The various current schemes for bubble devices require reproducible growth of very thin (0.10.5 micrometers) magnetic garnet films on garnet substrates (for submicron storage layers) or magnetic garnet layers for drive layers. Thickness and magnetic properties of these films depend on the liquid phase epitaxial growth temperature, the growth rate, and the growth time. Usual uncertainties in these parameters in conjunction with a normal melt result in a thickness variation of the order of +/- 0.1 micrometer, which is clearly unacceptable in view of the +10 percent tolerance for film thickness of 1 micrometer or less.

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Growth of Very Thin Magnetic Garnet Thin Films

The various current schemes for bubble devices require reproducible growth of very thin (0.10.5 micrometers) magnetic garnet films on garnet substrates (for submicron storage layers) or magnetic garnet layers for drive layers. Thickness and magnetic properties of these films depend on the liquid phase epitaxial growth temperature, the growth rate, and the growth time. Usual uncertainties in these parameters in conjunction with a normal melt result in a thickness variation of the order of +/- 0.1 micrometer, which is clearly unacceptable in view of the +10 percent tolerance for film thickness of 1 micrometer or less.

This problem is solved by diluting the fluxed melt by increasing the relative amount of flux and adjusting the amount of garnet constituents in the melt. It is known that melt dilution lowers the growth temperature and significantly slows down the growth rate. The lower growth temperatures change the segregation coefficients of the garnet constituents, so that their amounts in the melt have to be adjusted to obtain the proper composition dependent magnetic properties. The growth rate from these dilute melts is virtually independent of the growth temperature, and consequently it is possible to control the thickness to within +/- 0.01 micrometers.

Additional advantages of the slow growth rate dilute melts are: (a) Magnetic properties like anisotropy are no longer dependent on the growth temperature, and hen...