title: Resolution enhancement at a large convergence angle by a delta corrector with a CFEG in a low-accelerating-voltage STEM.
abstract: Resolution reduction by a diffraction limit becomes severe with an increase in the wavelength of an electron at a relatively low accelerating voltage. For maintaining atomic resolution at a low accelerating voltage, a larger convergence angle with aberration correction is required. The developed aberration corrector, which compensates for higher-order aberration, can expand the uniform phase angle. Sub-angstrom imaging of a Ge [112] specimen with a narrow energy spread obtained by a cold field emission gun at 60 kV was performed using the aberration corrector. We achieved a resolution of 82 pm for a Ge-Ge dumbbell structure image by high angle annular dark-field imaging.
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan. Electronic address: hsawada@jeol.co.jp.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Sawada
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Hosokawa
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan.
authors.forename: Kazutomo
authors.initials: K
authors.lastname: Suenaga
keywords: Corrector; Higher-order aberration; Ronchigram; STEM