Mechanism of the Smart Cut™ Layer Transfer in Silicon by Hydrogen and Helium Coimplantation in the Medium Dose Range

We investigate the mechanism of the Si layer transfer in the Smart Cut™ technology for H and He coimplantation in the dose range of (2.5–5)×1016cm−2. Using infrared spectroscopy and cross-section transmission electron microscopy we study the microstructure of defects formed in Si in the as-implanted state. With H preimplant we observe significant enhancement of damage production as compared to the case where He is implanted first. At higher coimplant doses a buried nonuniform amorphouslike layer is formed. The structure of the layer resembles “swiss cheese” with highly damaged but still crystalline pockets embedded into amorphous material. The effect of coimplantation parameters on the thickness and crystal quality of transferred layer is discussed in the framework of a simple phenomenological model.