Substrate with determinate thermal expansion coefficient

摘要

A composite support designed to successfully receive a transfer layer made of a crystalline material so that the assembly forms an epitaxy substrate, with the support having a longitudinal plane of symmetry parallel to its principal surfaces and a plurality of layers. The support includes a central first layer having a first thermal expansion coefficient at a specified temperature T and extending transversely on either side of the plane of symmetry and at least one pair of lateral layers. The layers of each pair, one with respect to the other, have arrangements in the composite support that are substantially symmetrical with respect to the plane of symmetry; second thermal expansion coefficients at the temperature T that are substantially identical to one another; and thicknesses that are substantially identical to one another. The layers of the support are made of materials that are chosen in such a way that the composite support has an overall thermal expansion coefficient at the temperature T that is sufficiently close to the thermal expansion coefficient of the material of the transferred layer at the temperature T to avoid generating an excessive number of defects in the transfer layer.