5.1 Although it would be desirable to measure the extent of profile distortion in any unknown sample by using a standard sample and this guide, measurements of interface width (profile distortion) can be unique to every sample composition (1, 2).4 This guide, describes a method that determines the unique width of a particular interface for the chosen set of operating conditions. It is intended to provide a method for checking on proper or consistent, or both, instrument performance. Periodic analysis of the same sample followed by a measurement of the interface width, in accordance with this guide, will provide these checks.

5.2 The procedure described in this guide is adaptable to any layered sample with an interface between layers in which a nominated element is present in one layer and absent from the other. It has been shown that for SIMS in particular (3, 4) and for surface analysis in general (5, 6), only rigorous calibration methods can determine accurate interface widths. Such procedures are prohibitively time-consuming. Therefore the interface width measurement obtained using the procedure described in this guide may contain significant systematic error (7). Therefore, this measure of interface width may have no relation to similar measures made with other methods. However, this does not diminish its use as a check on proper or consistent instrument performance, or both.

5.3 This guide can be used for both elemental and molecular depth profiles, provided that the materials have constant sputter rates throughout the depth of the overlayer, and minimal interlayer mixing is occurring. For more detailed information regarding measurements of interface widths during organic depth profiling, please see Mahoney (8).