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Transfer of thin Si layers by cold and thermal ion cutting

Research paper by K. Henttinen, T. Suni, A. Nurmela, H. V. A. Luoto, I. Suni, V.-M. Airaksinen, S. Karirinne, M. Cai, S. S. Lau

Indexed on: 01 May '03Published on: 01 May '03Published in: Journal of Materials Science: Materials in Electronics



Abstract

We have used the crack-opening method to study the mechanical exfoliation behavior in hydrogen-implanted and bonded Cz Si. We found that the crystal orientation and boron doping influence the temperature required for mechanical layer transfer. Boron implantation at doses >1013 cm−2 reduces the annealing temperature needed for mechanical exfoliation. The boron-doped epilayers followed similar exfoliation behavior as the boron-implanted samples. No lowering of the exfoliation temperature was observed for compensated and arsenic-doped Si layers. The hydrogen implantation converted the silicon wafer surface from p-type to n-type. The as-transferred Si layer was also found to be n-type after annealing at 200–450 °C. The p-type conductivity was restored upon annealing at around 600 °C. We believe that this conductivity conversion is due to the combined effect of ion-enhanced thermal donors and the presence of H-related shallow donors in the implanted layer. The p-type conductivity is restored at higher temperatures following the dissociation of the thermal donors and the out-diffusion of hydrogen. We also report that a good-quality silicon on glass layer can be obtained by the bonding and ion-cutting processes.