Low energy ion implantation into SOI substrates

Low energy ion implantation into silicon-on-insulator substrates will play a crucial role in the drive towards manufacturing ultra-shallow junctions. There is however a relative paucity of published material in this key area. In this work, the implantation and diffusion characteristics of boron and arsenic into thin UNIBOND
^®
SOI wafers have been investigated, as a function of energy, dose and thermal budget. Implants were carried out on an Applied Materials Quantum LEAP ion implanter, and subsequent RTP was undertaken on the Centura annealer. Implant energies were in the range 200eV-5keV for
¹¹
B+, and 1keV-10keV for
⁷⁵
As
⁺
. Electrical measurements were used to quantify the degree of dopant activation in implanted SOI wafers and these results were then compared to the values generated by identical low energy implants into bulk silicon. Dopant depth profiles were obtained using dynamic SIMS analysis of both as-implanted and annealed samples, with particular attention paid to identifying segregation of dopants at the buried interfaces.