Study of vertical Si/SiO2 interface using laser-assisted atom probe tomography and transmission electron microscopy

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Laser-assisted atom probe tomography (LA-APT) enables 3D visualization of nanostructures.
• Unresolved questions persist regarding laser-matter interactions in LA-APT.
• Accurate compositional analysis at interfaces is crucial for nanomaterial characterization.

Purpose of the Study:

• To investigate laser-activated interface reactions during field evaporation in LA-APT.
• To understand how these reactions affect the quantification of interfacial composition.
• To elucidate the influence of laser illumination direction and tip structure on these reactions.

Main Methods:

• Utilized laser-assisted atom probe tomography for 3D nanostructure analysis.
• Employed transmission electron microscopy (TEM) for pre- and post-experiment imaging.
• Analyzed Si/SiO2 vertical interfaces with varying tip structures and laser illumination.

Main Results:

• Demonstrated that interface reactions can be activated by laser-assisted field evaporation.
• Observed SiO molecule formation at Si/SiO2 interfaces, reducing evaporation field.
• Found that SiO concentration depends on laser direction and tip internal structure, with preferential Si evaporation noted.

Conclusions:

• Interface reactions significantly affect the quantification of interfacial composition in LA-APT.
• Laser-matter interactions, specifically SiO formation, must be considered for accurate analysis of Si/SiO2 interfaces.
• Optimizing laser parameters and understanding tip geometry are critical for reliable LA-APT results.