New layer transfers obtained by the SmartCut process

The SmartCut process was first developed to obtain silicon-on-insulator (SOI) materials. Now an industrial process, the main Unibond SOI-structure trends are reported in this paper. Many material combinations can be achieved by this process, because it appears to enable the generic development of new structures. Several of the new structures combining different materials and different bonding layers are described. These include SiGe and strained-Si films onto an oxidized Si wafer, silicon-on-insulating multilayer (SOIM) structures, and InP or 4H-SiC film transfers onto low-cost substrates via metallic or even refractory conductive-film bonding layers. More recently, an original bonding process based on mark patterning, wafer bonding, and layer transfer has been proposed to obtain structures in which the relative crystalline-axis orientations of both the film and the substrate can be controlled accurately. In this case, a SmartCut process that includes a mark-patterning step appears well suited for precise control of axis orientations. A procedure is described to obtain an ultra-thin Si film bonded onto a Si wafer. An example of a pure screw-dislocation network achieved by the mark patterning, bonding, and layer-transfer process is reported in this paper. The results have important implications for nanostructure development.