Patent FR-2895419-A1 (FR)
Title: Method of preparing an epitaxial structure, comprises depositing a material by columnar epitaxial growth on a crystalline surface of a substrate, and providing a substrate surface of a periodic projection network on nanometric scale
Inventor: FOURNEL FRANK
IPC: H01L21/20
Filed: 2005-12-27
Abstract: The method of preparing an epitaxial structure, comprises depositing a material by columnar epitaxial growth on a crystalline surface of a substrate, providing a substrate surface of a periodic projection network on a nanometric scale, preparing the substrate surface equipped with the projection network of two elements, and treating the projection network to adjust a height and/or size of a support zone (35) of the projections and/or to modify a mesh parameters of projection material. The material is deposited until- the columns rejoin and the formation of a continuous layer (5). The method of preparing an epitaxial structure, comprises depositing a material by columnar epitaxial growth on a crystalline surface of a substrate, providing a substrate surface of a periodic projection network on a nanometric scale, preparing the substrate surface equipped with the projection network of two elements, and treating the projection network to adjust a height and/or size of a support zone (35) of the projections and/or to modify a mesh parameters of projection material. The material is deposited until- the columns rejoin and the formation of a continuous layer (5). Each projection has the support zone for the column (4). The projection is obtained directly/indirectly from a crystal defects network and/or stress fields created within in a crystalline zone located in a vicinity of an interface, which is joined between two elements. The elements comprise crystalline material and mismatched crystalline lattice arranged in rotation, flexion and/or a discrepancy of lattice parameters at the interface. The crystalline zone is intended for conditioning a period of projection network in which the height of the projections and size of the support zone are adjusted to form a critical thickness (39) higher than the continuous layer obtained at a time of an epitaxy carried out in an absence of projections. The material deposited by the epitaxy has a natural mesh parameter. The period of the network, the height of the projections and size of the support zone are adjusted so that the material deposited by epitaxy find the natural mesh parameter when the columns meet. The two elements are adhered by thinning one of the elements until revealing a relief from surface crystalline defects network and/or stress fields. The relief forms the projection network, which is supported by the other element. The thinning comprises a stage of a mechanical abrasion, a chemical abrasion, correction and sacrificial treatment. The projection network treatment comprises an implantation stage and a contribution of a thermal budget. The thinning and/or projection network treatment comprises a stage of chemical attack, electrochemical attack, mechanical attack, ionic attack, photochemical attack and/or a deposit, under oxidizing/reducing atmosphere. The elements are formed by a same crystalline structure (2), which is taken in two parts. The parts contribute for the formation of the interface by collage. During collage the two parts of the crystalline structure have the crystalline lattice, which is shifted by rotation and/or flexion of a predetermined angle. The crystalline structure comprises a location mark having two parts. The location mark is useful for adjusting a shift angle. An element is a silicon-on-insulator formed by a stacking of a support, a barrier layer by thinning of the support, and a crystalline layer. The collage is carried out by molecular adhesion. A composition of deposited material varies during the deposition by epitaxy. The substrate surface provided with the projection network performs duplication of a master substrate, which is obtained from two stuck elements and by thinning stage. The duplication is carried out by nanoimpression of a mold, which is complementary to the master substrate. The mold is obtained by nanoimpression of the master substrate. An independent claim is included for an epitaxial structure.