Fourier analysis of HRTEM image deterioration caused by mechanical vibration

Contrast deterioration of high-resolution transmission electron microscope (HRTEM) images, that is caused by mechanical vibrations of the turbo molecular pump (TMP), was systematically and quantitatively investigated on the basis of Fourier analysis using plural images. It was demonstrated that TEM image contrast was considerably deteriorated by the resonance of mechanical vibration at specific rotational speeds of the TMP. By setting a TMP rotational speed from 48,000 rotations per minute (rpm) to 41,000 rpm, apart from the mechanical resonance frequencies of the present apparatus, the information limit of the observed image was improved from 6 nm-1 to 7 nm(-1).