CBE Interdisciplinary Glossary

A good metaphor to explain the difference between Auger and EDAX is that: Auger sees the "grass and roots" at best; but EDAX sees the "soil" deep down beneath.

Surface Science

MATERIALS WHICH CAN BE ANALYZED
Auger  Conducting or semi-conducting materials. Can detect all elements except hydrogen.

EDAX  All materials that can be put in a high vacuum system. Insulating materials need to be coated with a conducting layer of C or Au. Can do a quantitative elemental analysis and detect all elements.

RESOLUTION Spatial Resolution: Auger can resolve down to 1000A (0.1 mm); however, typical spot size for point analysis is about 3000A (0.3 um) in our system. SEM can resolve down to 50A; however, typical interaction volume of x-ray analysis varies between 100A to 10,000A. Important note: In general, SEM images have much better spatial resolution than the x-ray maps.

SUBSTRATUM A surface on which biological or chemical reaction occurs.

SURFACE A solid and vacuum, solid and air, or solid and liquid interface which is under study. Depth of analysis depends on the analytical technique being used: Auger, XPS, ToFSIMS: The analysis depth ranges from 5A to 50A. EDAX: The analysis depth varies from 100A to 10,000A (1mm).

ToFSIMS  All materials (conducting or non-conducting) that can be put in UHV. As in Auger and XPS, the materials need no coating. Can detect fragmentation patterns of molecules and determine the long-range chemistry of compounds with high accuracy. Can detect all elements and compounds.

XPS   All materials (conducting or non-conducting) that can be put in ultra-high vacuum (UHV). Can identify chemical compounds and provide information on the short-range chemical bond structure.

Table of Contents

Terms & Concepts by Discipline

Index