Direct measurement of inhomogeneous longitudinal dopant distribution in SiNVVs using nano-probe scanning auger microscopy

Controlled incorporation of dopants into semiconductors nanowires is a critical step in tailoring their physical properties and hence for their utilization in future nano electronic devices. Recently, several studies addressing this issue revealed that dopant are inhomogeneously distributed in NWs grown by the popular CVD-VLS growth technique. The majority of those studies employed indirect characterization techniques which are sensitive to the active dopants only. In order to deepen our understanding of the incorporation mechanism a direct observation of the dopant chemical concentrations is required. In addition, the comparison between direct and indirect observations can shed some light on the dopant activation mechanisms in VLS grown NWs. In this study nanoprobe scanning Auger microscopy was employed to extract the longitudinal dopant distribution along P doped SiNWs. The effect of growth conditions and post-growth annealing on this distribution was studied and compared to previous studies which used indirect measurement techniques. In addition, dopant modulated segmented NWs were studied in order to distinguish the contribution of different mechanisms to the incorporation of dopants into VLS grown NWs.