Abstract
Today, the Smart Cut TM technology is currently used to transfer sub-micrometer thick layers of many crystalline materials (Si, Ge, SiGe, GaN, SiC, Ferroelectrics) onto various substrates. This technology is based on the ion implantation of hydrogen and/or helium in the material to be transferred and on the bonding of this material onto another material, followed by thermal annealing.In this talk, we will review the knowledge we have recently gained of the different mechanisms by which the implanted H/He evolve during annealing finally leading to the fracture and separation of the surface layer.We will identify the different defects which play a role in this phenomenon (VnHm complexes, platelets, micro-cracks) and of the mechanisms by which they grow and eventually transform from one into the other. This discussion will be based on large collection of TEM, Raman, FTIR and X-rays data, including direct imaging of some of these transformations in situ, in the microscope. Finally, we will identify and discriminate the mechanisms driving “gentle” transformations dictated by thermodynamics (nucleation, diffusion, Ostwald ripening) from those driving “catastrophic” transformations (strain assisted coalescence, fracture propagation). Remaining questions to be answered before the full simulation of the process is thinkable will be indicated. The possible extension of this technology to the direct transfer of ultra-thin layers (<50 nm) will be discussed.
