The accuracy of electron energy-loss spectroscopy (EELS) and electron holography on thickness measurement of amorphous SiO2 was discussed. Since the SiO2 particles investigated in this work have a spherical shape, local thickness along the incident electron beam can easily be evaluated. Thus, from EELS, the mean free path of inelastic scattering was determined to be 178±4 nm at 200 kV. It is considered that thickness measurement is limited to amorphous SiO2 film thicker than about 20 nm with EELS. On the other hand, from phase shift in the electron hologram, the mean inner potential was evaluated to be 11.5±0.3 V. It is suggested that the thickness measurement is possible up to a few nanometers with electron holography. Thus, it is pointed out that the accurate thickness measurement is possible for a thinner region with electron holography than EELS.
ASJC Scopus subject areas