Determination of Inelastic Mean Free Path by Electron Energy-Loss Spectroscopy in TEM: A Model Study using Si and Ge


Although the inelastic mean free path for Si and Ge have been measured previously, reported experimental values for silicon range from 121 nm to 160 nm for 200 keV and a large collection angle. A key factor responsible for this uncertainty is the lack of an accurate measurement of the specimen thickness at the point at which the EELS spectra are obtained. In this research, we have evaluated a systematic methodology for determination of the specimen thickness. In the thickness measurement based on converging beam electron diffraction, CBED, instead of the classic “trial and error” straight-line-fitting method to either the maxima or minima, a non-linear least square fitting of the theoretical diffraction profile to the energy filtered two-beam CBED is used. The low-loss EELS spectrum is also obtained from the same location. The inelastic mean free path was determined using the measured thickness and EELS data.

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Correspondence to Chongmin Wang.

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Wang, C., Cannon, B.D. Determination of Inelastic Mean Free Path by Electron Energy-Loss Spectroscopy in TEM: A Model Study using Si and Ge. MRS Online Proceedings Library 982, 713 (2006).

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