Resolving the Electron Plume within a Scanning Electron Microscope

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Scanning Electron Microscopy (SEM) is a standard technique for imaging nanostructures.
• Conventional SEM detectors primarily count secondary electrons, neglecting valuable material information.
• Existing methods often lack the capability to probe subsurface electronic properties non-invasively.

Purpose of the Study:

• To enhance SEM by resolving secondary electron momentum and energy information.
• To develop a spectroscopic imaging capability for advanced material analysis.
• To enable non-destructive probing of subsurface electronic properties in semiconductor devices.

Main Methods:

• Simple modifications to a standard SEM instrument.
• Direct imaging of the electron plume generated by the SEM's electron beam.
• Spectroscopic analysis of secondary electrons to extract momentum and energy data.

Main Results:

• Successfully imaged lateral electric fields across silicon p-n junctions.
• Distinguished differently doped semiconductor regions, including buried layers.
• Revealed significant surface band bending in passivated semiconductor structures.

Conclusions:

• The modified SEM offers non-invasive, multimodal probing of electronic components.
• This technique provides crucial insights into interfacial dynamics and device operation.
• Extended SEM capabilities unlock new possibilities for analyzing complex material properties.