Surface Effect on SEM Voltage Contrast and Dopant Contrast

The Voltage Contrast (VC) [1-3] and Dopant Contrast [4-7] in Scanning Electron Microscopy (SEM) [8] have been widely used in the Silicon (Si) semiconductor manufacturing field to localize the failure site from plane-view and inspect the doping profile along cross-section with spatial resolution in the nanometer (nm) range. In this article, we demonstrate how the surface effect, such as topography or material variation, impacts the conventional prediction for the voltage and dopant contrast in the SEM images. The mechanisms and applications for the SRAM and real products are described.