Segregation behaviors and radial distribution of dopant atoms in silicon nanowires

Understanding the dynamic behaviors of dopant atoms in Si NWs is the key to realize low-power and high-speed transistors using Si NWs. The segregation behavior of boron (B) and phosphorus (P) atoms in B- and P-doped Si NWs (20 nm in diameter) during thermal oxidation was closely analyzed.

Local vibrational peaks and Fano broadening in optical phonon peaks of B-doped Si NWs were used to detect the behavior of B. Electron spin resonance (ESR) signals from conduction electrons were suitable means for P-doped Si NWs.

The radial distribution of P atoms in Si NWs was also investigated to prove the difference in segregation behaviors between of P and B atoms.

B atoms were found to segregate preferentially in the surface oxide layer, whereas P atoms tend to accumulate around the interface inside the Si nanowire.

In addition, segregation of B atoms was found to be suppressed by the stress applied to Si NWs.

More information: Naoki Fukuda, Shinya Ishida, Shigeki Yokono, Ryo Takiguchi, Jun Chen, Takashi Sekiguchi, and Kouichi Murakami, "Segragation Behaviors and Radial Distribution of Dopant Atoms in Silicon Nanowires", NANO Letters (2011) doi: 10.1021/nl103773e Published online 24 January 2011.

Provided by National Institute for Materials Science