Defect distribution in boron doped silicon nanostructures characterized by means of scanning spreading resistance microscopy

Abstract

Scanning spreading resistance microscopy (SSRM) was applied on boron (B) doped bulk and nanostructured silicon (Si) samples. Finite element simulations are performed to calculate the expected resistance profile based on secondary ion mass spectrometry data of the chemical B profile. Differences between experimental and simulated resistance scans are consistently described by the interaction of electrically active dopants with defect states. These states are strongly correlated to the cross-sectional sample preparation applied before the SSRM analysis. Whereas the B-doped bulk sample only reveals preparation induced bulk and surface defects, the SSRM scan of B-doped Si pillars is additionally affected by interface defects at the outer shell of the pillar. These interface defects do not only affect the concentration of charged carriers in the Si pillar but could also influence dopant diffusion in nanostructured Si.