Atomic-Scale Characterization of N-Doped Si Nanocrystals Embedded in SiO₂ by Atom Probe Tomography

Structural properties of undoped, As-doped, and P-doped silicon nanocrystals (Si-Ncs) embedded in a SiO₂ matrix have been investigated using atom probe tomography. It turns out that both As and P atomic distributions have the same behavior in such system, withthe efficient incorporation of impurities in the core of Si-Ncs even in the smallest ones (<2 nm). The impurity level measured in Si-Ncs is strongly size-dependent, and statistically, the smallest Si-Ncs can contain the heaviest doping composition. Moreover, this study reveals an influence of the dopant nature on the kinetic growth of Si-Ncs, leading to the clustering of larger nanocrystals in P-doped samples.