The Applications ofIn SituElectron Energy Loss Spectroscopy to the Study of Electron Beam Nanofabrication

Abstract

An in situ electron energy loss spectroscopy (EELS) technique has been developed to investigate the dynamic processes associated with electron-beam nanofabrication on thin membranes. In this article, practical applications germane to e-beam nanofabrication are illustrated with a case study of the drilling of nanometer-sized pores in silicon nitride membranes. This technique involves successive acquisitions of the plasmon-loss and the core-level ionization-loss spectra in real time, both of which provide the information regarding the hole-drilling kinetics, including two respective rates for total mass loss, individual nitrogen and silicon element depletion, and the change of the atomic bonding environment. In addition, the in situ EELS also provides an alternative method for endpoint detection with a potentially higher time resolution than by imaging. On the basis of the time evolution of in situ EELS spectra, a qualitative working model combining knock-on sputtering, irradiation-induced mass transport, and phase separation can be proposed.

A novel shaped-controlled fabrication of nanopore and its applications in quantum electronics

“…Figure 1(a) shows a schematic of the electron beam used to drill nanopores on a silicon nitride membrane which was subsequently observed with TEM. When the high-intensity () electron beam was used to drill nanopores on a silicon nitride membrane, a nanopore with an hourglass shape could be formed with sputtering 25–28 . The use of the high-intensity electron beam for the illumination of the nanopore narrowed the sharp edge of the hourglass shape to a cylindrical shape, and resulted in the destruction of the original shape 29 .…”

TEM-HRTEM study on the dehydration process of nanostructured Mg–Ca hydroxide into Mg–Ca oxide

“…Although High-Resolution Transmission Electron Microscopy (HRTEM) is primarily a technique for studying bulk defects, it has been applied in the profile-imaging mode to derive information about surfaces [6]. Nowadays the EELS spectroscopy provides excellent alternatives to monitor the time evolution of chemical reactions [7,8].…”

Three-dimensional structures of magnesium nanopores

“…Although sputtering occurs mainly at the bottom side of the TEM specimen [37][38][39], the material loss from the top surface may be contributed by the generation and movement of vacancies or voids from the back-sputtering interface towards the top surface along the 1100 { ¯} planes [12,40]. Meanwhile, due to the Gauss intensity distribution around the central intense point of the e-beam [41], the sputtering is angled on both sides of the membrane, which leads to a wedge-shaped section surrounded by the 1101 { ¯} and 0001 { } planes with relatively lower surface energies, as illustrated in figures 5(a) and (d) [27,29]. It is worth noting that the sidewall angle in the cross section is constant (calculated to be about 62°), which differs from that in isotropic amorphous materials whereas the angle varied closely associated with material composition, precise drilling conditions (e-beam size, beam intensity), etc [9,12,[18][19][20][21].…”