QUANTITATIVE ANALYSIS OF NONCONTINUOUS THIN FILMS BY EELS

Abstract

Reflection electron energy loss spectroscopy (EELS) operated at low primary electron energy Ep (~ 500 eV) can be used as a coverage-sensitive probe in the case of supported noncontinuous layers. Quantitative analysis by EELS is substantially complicated by the fact that EEL intensity depends on two material factors: K(E), differential cross section for energy loss of E, and electron backscattering factor η(Ep). Both factors were determined experimentally using deposit and substrate reference samples. The contribution of pure substrate and pure deposit EEL curves to composed EEL spectra of the investigated deposit/substrate system has been found by fitting it with combination of reference K(E)λ curves (λ stands for IMFP). The fit results corrected using η(Ep) factors permitted one to evaluate the deposit coverage. The method was tested using the reference Au fractional deposit on the sapphire substrate.