Comparative study of image contrast in scanning electron microscope and helium ion microscope

Area of Science:

• Materials Science
• Surface Science
• Microscopy

Background:

• Gallium (Ga⁺) implantation is used to modify amorphous silicon properties.
• Scanning electron microscopy (SEM) and helium ion microscopy (HIM) are advanced imaging techniques.
• Understanding image contrast is crucial for accurate material characterization.

Purpose of the Study:

• To investigate the effects of Ga⁺ implantation dose and imaging parameters on image contrast.
• To compare the contrast behavior in SEM and HIM.
• To assess the impact of dynamic charging on image quantification.

Main Methods:

• Imaging of Ga⁺ implanted amorphous silicon layers in n-type silicon substrates.
• Utilizing various detectors in SEM (Inlens) and HIM (Everhart-Thornley).
• Systematic variation of implantation dose and imaging parameters (beam energy, dwell time).

Main Results:

• A similar relationship was observed between image contrast and Ga⁺ density across both SEM and HIM detectors.
• Imaging parameters significantly influence image contrast in both microscopy techniques.
• Dynamic charging effects were found to impact the quantification of contrast in both SEM and HIM.

Conclusions:

• SEM and HIM exhibit comparable contrast responses to Ga⁺ density and imaging parameters in amorphous silicon.
• Accurate quantification of HIM and SEM images requires accounting for dynamic charging effects.
• This comparative study provides insights into optimizing imaging protocols for ion-implanted materials.