Published online by Cambridge University Press: 02 July 2020
MBE techniques allow the fabrication of exceptionally sharp compositional changes such as delta doped layers in semiconductors. Producing these spatially confined doped layers is critical to many innovative device designs. The spatial confinement of these delta doped structures can be less than the measurement resolution of the currently standard SIMS and RBS techniques. This allows only the upper limits on the layer width to be measured. These SIMS and RBS methods are also inadequate for the two dimensional information desired for future device design and development. More recently developed techniques such as Scanning Capacitance Microscopy and spreading resistance measurement give two dimensional information but have similar spatial resolution issues. The Z-contrast nature of Annular Dark Field (ADF) imaging with the complimentary technique of Electron Energy Loss Spectroscopy (EELS) in the Scanning Transmission Electron Microscope (STEM) shows promise for two dimensional dopant profiling with spatial resolution on the atomic scale.