Apparent beam size definition of focused ion beams based on scanning electron microscopy images of nanodots

Abstract

In this paper, the new term apparent beam size of focused ion beam (FIB) is introduced and an original method of its evaluation is demonstrated. Traditional methods of measuring the beam size, like the knife edge method, provide information about the quality of the beam itself, but practically, they do not give information on the FIB sputtering resolution. To do this, it is necessary to take into account the material dependent interaction of the beam with the specimen and the gas precursor in the vacuum chamber. The apparent beam size can be regarded as the smallest possible dot that FIB can sputter in a given specimen. The method of evaluating it, developed in this paper, is based on the analysis of a series of scanning electron images of FIB produced nanodots. Results show that the apparent beam size can be up to five times larger than the actual physical size of the beam and it is significantly influenced by the presence of gas precursor. It is also demonstrated that the apparent beam size can be used as a reference value for optimization of the beam step during raster scanning.

Unmasking the Resolution–Throughput Tradespace of Focused‐Ion‐Beam Machining

“…[ 28 ] Previous studies have taken different approaches to analyze the resulting images, yielding different combinations of efficiency and accuracy. Simple approximations without uncertainty evaluation [ 9 ] are unsuitable for dimensional metrology, whereas accurate physical models [ 29 ] of scanning electron microscopy require energy-loss functions of the constituent materials. Historically, these functions have required synchrotron measurements to obtain.…”

“…[ 8 ] For dielectric substrates, exposure to an ion beam results in electrostatic charging and repulsion of ions from the surface, further complicating the process of focusing the ion beam and degrading lateral and vertical resolution. The lateral extent of the ion-beam profile generally follows a power-law dependence on ion-beam current, with effective lateral resolution requiring characterization [ 9 ] for specific ion sources and substrate materials. Accordingly, reducing the lateral extent of the focused ion beam, simply by decreasing the current, generally improves lateral resolution and decreases the accumulation of charge.…”

Influence of Ga+ milling on the spin waves modes in a Co2MnSi Heusler magnonic crystal

“…The distances over which implantation and lateral damage spread are material dependent 69 . To evaluate them, we performed SRIM (Stopping and Range of Ions in Matter) simulations 70 .…”

Influence of the Shave-off Scan Speed on the Cross-Sectional Shape

“…According to a report by Vladov et al [5], the effective footprint of a beam which causes damage to the surface is larger than the physical size of the beam, and they defined the effective footprint as an apparent beam size. From the results shown in Fig.…”