A multichannel electron energy loss spectrometer for low-temperature condensed films

ABSTRACTWe have employed reflection electron energy loss spectrometry (REELS), a surface chemical analysis technique, in order to analyze contaminant coverages at the submonolayer level during low-temperature in situ cleaning of hydrogen-terminated Si(100). The chemical composition of the surface was analyzed by measurements of the C K, O K and Si L2,3 core loss intensities at various stages of the cleaning. These results were quantified using SiC(100) and SiO2 as reference standards for C and O coverage. Room temperature REELS core loss intensity analysis after sample insertion reveals carbon at fractional monolayer coverage. We have established the REELS detection limit for carbon coverage to be 5±2% of a monolayer. A study of temperature-dependent hydrocarbon desorption from hydrogen-terminated Si(100) reveals the absence of carbon on the surface at temperatures greater than 200°C. This indicates the feasibility of epitaxial growth following an in situ low-temperature cleaning and also indicates the power of REELS as an in situ technique for assessment of surface cleanliness.

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High resolution electron energy loss spectrometer for the study of vapor phase samples

Journal of Electron Spectroscopy and Related Phenomena ◽

10.1016/j.elspec.2006.11.015 ◽

2007 ◽

Vol 156-158 ◽

pp. 145-149 ◽

Cited By ~ 4

Author(s):

S. Urpelainen ◽

M. Huttula ◽

P. Kovala ◽

A. Mäkinen ◽

A. Caló ◽

...

Keyword(s):

High Resolution ◽

Energy Loss ◽

Electron Energy ◽

Vapor Phase ◽

Resolution Electron ◽

Electron Energy Loss Spectrometer ◽

Electron Energy Loss

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A New High Performance Electron Energy Loss Spectrometer for use with Monochromated Microscopes

Microscopy and Microanalysis ◽

10.1017/s1431927600030610 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 908-909

Author(s):

H.A. Brink ◽

M. Barfels ◽

B. Edwards ◽

P. Burgner

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Energy Resolution ◽

Optical Design ◽

Electron Source ◽

High Voltage Power Supply ◽

Electron Energy Loss Spectrometer ◽

Electron Microscopes ◽

Electron Energy Loss ◽

Better Than

A new type of electron energy loss spectrometer for use with monochromated microscopes is presented. The energy resolution of the spectrometer is better than 0.100 eV. A completely new electron optical design with a number of extra optical elements and advanced tuning software makes it possible to correct spectrum aberrations to 4th order, which increases sensitivity and collection angles. New high-stability electronics make it possible to maintain energy resolution over a period of several minutes in a practical laboratory environment.The energy resolution of Transmission Electron Microscopes (TEMs) equipped with electron energy loss spectrometers is determined by a combination of the energy spread of the electron source, the stability of the microscope’s high voltage power supply, and the energy resolution of the spectrometer. Commercial microscopes usually employ electron sources with an energy distributions of around 0.5 eV or more (FWHM), limiting the energy ultimate energy resolution that can be achieved. Recently FEI constructed a special 200 kV TEM with a built-in monochromator which makes it possible to monochromize the electron source to better than 0.100 eV. A prototype of the presented spectrometer has been installed on this microscope.

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