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AssigneeThompson-CSF
InventorsLinh N. Trong, Jean Chevrier
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An epitaxial structure in which a constraint imposed by forced epitaxy causes an increase in the piezoelectric effect of a group of layers. The structure which provides this effect utilizes a semi-insulating substrate made from a first material on which is deposited by forced epitaxy a layer of a second material, the two materials are in crystalline mesh parameter disharmony, which creates in said layer a constraint increasing its piezoelectricity. On the constrained layer are deposited two groups of alternated "deforming" and "deformed" layers of the two materials. The thickness of the structure is sufficient to allow propagation of the surface waves. The advantage of this structure is that it allows two transducers such as transistors to be integrated on or at the side of this structure.
In an epitaxial structure with piezoelectric effect, comprising, supported by a semi-insulating substrate, a plurality of epitaxied layers, said epitaxied layers form two groups of layers, formed from two regularly alternated materials, the first material of the first group of layers having a crystalline mesh parameter equal to that of the substrate, the second material of the second group of layers having a crystalline mesh parameter different from that of the substrate and being more piezoelectric, the disharmony of the crystalline parameter between the substrate and the layers of the first group imposing on the layers of said second group a constraint deforming the crystalline network which increases the piezoelectric effect.
Dependencies are inferred from the claim text.