Effect of the order of He+ and H+ ion co-implantation on damage generation and thermal evolution of complexes, platelets, and blisters in silicon

Hydrogen and helium co-implantation is nowadays used to efficiently transfer thin Si layers and fabricate silicon on insulator wafers for the microelectronic industry. The synergy between the two implants which is reflected through the dramatic reduction of the total fluence needed to fracture silicon has been reported to be strongly influenced by the implantation order. Contradictory conclusions on the mechanisms involved in the formation and thermal evolution of defects and complexes have been drawn. In this work, we have experimentally studied in detail the characteristics of Si samples co-implanted with He and H, comparing the defects which are formed following each implantation and after annealing. We show that the second implant always ballistically destroys the stable defects and complexes formed after the first implant and that the redistribution of these point defects among new complexes drives the final difference observed in the samples after annealing. When H is implanted first, He precipitate...