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Preventing Fracture in Garnet Films by Masking Film Growth

IP.com Disclosure Number: IPCOM000080135D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Klokholm, E: AUTHOR [+2]

Abstract

Crack nucleation during epitaxial growth of garnet materials and during dicing, is prevented by deposition of a platinum (Pt) prior to garnet growth.

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Preventing Fracture in Garnet Films by Masking Film Growth

Crack nucleation during epitaxial growth of garnet materials and during dicing, is prevented by deposition of a platinum (Pt) prior to garnet growth.

Materials for bubble domain application require an easy direction of magnetization normal to the film. In garnet materials, which have a cubic structure, this is obtained either by a stress mechanism or by growth mechanism. (GdY)(3)(GaFe)(5)O(12) is an example of a garnet system where the anisotropy is stress induced. The stress is generated by a room temperature lattice mismatch, and by a thermal coefficient of expansion difference between the substrate (Gd(3)Ga(5)O(12)) and the film. The stresses required are large (about 10/9/ dynes/cm/2/) and under certain conditions can cause the film to fracture.

Most of the film fractures nucleate at highly strained areas in the substrate at the substrate periphery. Film fractures would also occur during the dicing operation for device construction. The additional stress due to the dicing would tend to nucleate film cracking.

This description relates to a method for the prevention of cracking at the substrate periphery and as well as to the possible cracking during dicing. It has been observed that garnet films grown by liquid phase epitaxy techniques will not deposit on Pt metal. Furthermore, the Pt does not dissolve in the melt. As shown in the figure, Pt is deposited at the periphery of the substrate in such a mann...