title: Highly reproducible secondary electron imaging under electron irradiation using high-pass energy filtering in low-voltage scanning electron microscopy.
abstract: The reproducibility of contrast in secondary electron (SE) imaging during continuous electron irradiation, which caused surface contamination, was investigated using SE high-pass energy filtering in low-voltage scanning electron microscopy (SEM). According to high-pass energy-filtered imaging, dopant contrast in an indium phosphide remained remarkably stable during continuous electron irradiation although the contrast in unfiltered SE images decreased rapidly as a contamination layer was formed. Charge neutralization and the SE energy distributions indicate that the contamination layer induces a positive charge. This results in a decrease of low-energy SE emissions and reduced dopant contrast in unfiltered SE images. The retention of contrast was also observed in high-pass energy-filtered images of a gold surface. These results suggest that this imaging method can be widely used when SE intensities decrease under continuous electron irradiation in unfiltered SE images. Thus, high-pass energy-filtered SE imaging will be of a great assistance for SEM users in the reproducibility of contrast such as a quantitative dopant mapping in semiconductors.
authors.affiliation: Analysis Technology Research Center, Sumitomo Electric Industries, Ltd., 1 Taya-cho, Sakae-ku, Yokohama, Kanagawa 244-8588, Japan. tsurumi-daisuke@sei.co.jp
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tsurumi
authors.forename: Kotaro
authors.initials: K
authors.lastname: Hamada
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kawasaki