Interaction of Boron and Phosphorus Impurities in Silicon Nanowires during Low-Temperature Ozone Oxidation

摘要

In doped Si nanowires (SiNWs) boron (B) atoms segregate to the surface oxide layers during thermal oxidation, while phosphorus (P) atoms preferentially pile up in Si crystalline regions close to the Si/SiO2 interface. Here we report on micro-Raman scattering and electron spin resonance (ESR) measurements showing that B atoms can be stabilized at the crystalline Si core region in codped SiNWs with average diameters of 20—30 nm because of the strong interaction between B and P atoms during thermal oxidation below 800 °C. Theoretical calculation clearly demonstrated the effect of B—P pairing, which can stabilize the B atoms in the Si side. In the B—P pairing configuration, dopant passivation—beyond simple compensation—occurs, making the impurities electrically inactive.