ARCtick - Software to assist in Depth Profiling by Angle-Resolved XPS

At NPL we have developed a computer spreadsheet, named ARCtick which allows one to apply the simplest and most reliable approaches for Angle Resolved XPS (ARXPS).

What is Angle-Resolved XPS Depth-Profiling?

Angle-Resolved X-ray photoelectron spectroscopy (ARXPS) can be used non-destructively to define the depth-distribution of chemical species. Often one needs a simple qualitative result, such as that "layer A" is above (or below) "layer B". In these simple cases one examines how the ratio of the two peak intensities changes as one tilts the specimen close to grazing emission. Sometimes one needs to use ARXPS quantitatively. This is often the case if chemical state information from the first 5nm or so is needed, since this is very rapidly destroyed by alternative depth-profiling methods involving sputtering. By acquiring spectra at a few different angles of emission we are typically trying to answer one of four types of question:

• Thickness Measurement (TM) - e.g. "What is the thickness of this aluminium oxide?"
• Depth Measurement (DM) - e.g. "What is the average depth of this low energy implant?"
• Layer Modelling (LM) - e.g. "What is the order of the layers in a complex oxide, and how thick are they?"
• Depth Profile (DP) - e.g. "How does the concentration of different oxidation states of carbon vary with depth over the first few nanometres in this bio-compatible material?"

What is ARCtick?

At NPL we have reviewed the twenty or so different quantification algorithms proposed since 1974 for solving problems like these. One can classify them into families. Most recently we have developed a computer spreadsheet, named ARCtick which allows one to apply the simplest and most reliable approaches to answer questions of this kind, and incorporate one's prior knowledge about the specimen. The use of some graphics and the standard user interface controls make the spreadsheet reasonably user-friendly. Prior knowledge turns-out to be extremely important, especially for the more challenging methods, which give a depth profile.

Download ARCtick Angle-Resolved XPS software ( ZIP, 650 kB). This file contains the ARCtick spreadsheet and user manual.