Segregation behaviors and radial distribution of dopant atoms in silicon nanowires.

Gaining an understanding the dynamic behaviors of dopant atoms in silicon nanowires (SiNWs) is the key to achieving low-power and high-speed transistor devices using SiNWs. The segregation behavior of boron (B) and phosphorus (P) atoms in B- and P-doped SiNWs during thermal oxidation was closely observed using B local vibrational peaks and Fano broadening in optical phonon peaks of B-doped SiNWs by micro-Raman scattering. Electron spin resonance (ESR) signals from conduction electrons were used for P-doped SiNWs. Our results showed that B atoms preferentially segregate in the surface oxide layer, whereas P atoms tend to accumulate in the Si region around the interface of SiNWs. The radial distribution of P atoms in SiNWs was also investigated to prove the difference segregation behaviors between of P and B atoms.

Recrystallization and reactivation of dopant atoms in ion-implanted silicon nanowires.

Recrystallization of silicon nanowires (SiNWs) after ion implantation strongly depends on the ion doses and species. Full amorphization by high-dose implantation induces polycrystal structures in SiNWs even after high-temperature annealing, with this tendency more pronounced for heavy ions. Hot-implantation techniques dramatically suppress polycrystallization in SiNWs, resulting in reversion to the original single-crystal structures and consequently high reactivation rate of dopant atoms. In this study, the chemical bonding states and electrical activities of implanted boron and phosphorus atoms were evaluated by Raman scattering and electron spin resonance, demonstrating the formation of p- and n-type SiNWs.