Delta Type Spherical Aberration Corrector

Hidetaka Sawada, Takeo Sasaki, Shuuichi Yuasa, Mitsuhisa Terao, Muneyuki Kawazoe, Tomohiro Nakamichi, Fumio Hosokawa, Toshikatsu Kaneyama, Yukihito Kondo, Koji Kimoto and Kazutomo Suenaga

Abstract: We have developed a spherical aberration correction system with three dodeca-poles. This system corrects a six-fold astigmatism, which generally limits a uniform phase area for image forming and probe forming system in an electron microscope with the conventional two-hexapole corrector. Experimental results showed compensation of a six-fold astigmatism as well as spherical aberration. We experimentally demonstrated high-resolution images with this corrector in a transmission electron microscope and a scanning transmission electron microscope at 30-kV and 60-kV acceleration.

Key words: Aberration correction, Low voltage, Higher order aberration,