Patent ID: 8105916

Claim:
A process for fabricating a heterostructure comprising a multilayer stack in which an upper layer comprises an at least partially relaxed thin film of crystalline material, the process comprising: providing a thin film of crystalline material in a strained state on an intermediate substrate; depositing a strain relaxation layer comprising a layer of crystalline material on the thin film of crystalline material in the strained state; selecting the crystalline material of the strain relaxation layer to be plastically deformable by a heat treatment at a relaxation temperature at which the crystalline material of the thin film of crystalline material deforms by elastic deformation; transferring the thin film of crystalline material and the strain relaxation layer together onto a support substrate and forming an intermediate heterostructure wherein the layer of crystalline material of the strain relaxation layer is interposed between the support substrate and the thin film of crystalline material, a first side of the layer of crystalline material of the strain relaxation layer being in direct contact with the thin film of crystalline material, and a second side of the layer of crystalline material being directly bonded to the support substrate; and heating the intermediate heterostructure to at least the relaxation temperature and causing plastic deformation of the strain relaxation layer and at least partial relaxation of the thin film of crystalline material by elastic deformation to provide the heterostructure.