Thermal-Annealing Effects on Dopant Redistribution in Nanoscale Si Fin

Abstract

We investigated the diffusion of implanted boron and phosphorous in a narrow Si fin during rapid thermal annealing (RTA) at 1000 °C for 10 s. We found that the boron diffusion is described by the conventional diffusion model. We also found that the point defects (interstitial Si and vacancy) play an important role in determining the detailed distribution of boron in a narrow Si fin. On the other hand, the phosphorous diffusion shows anomalous behavior in the peak region of the Si fin, namely large dose loss from the Si region. We found experimentally that about 50% of implanted phosphorous atoms in the Si fin diffused out from the Si region by the annealing (1000 °C, 10 s). The simulation result shows that the experimental result of phosphorous diffusion is reproduced by taking into account the dose loss model through introduction of the interfacial trap layer. Because the phosphorous distribution is largely modified by the dose loss effect, it is considered that the large dose loss of phosphorous gives rise to large impacts on the device characteristics of fin field effect transistors (FinFETs).