Toward a better reliability in the deconvolution of SIMS depth profiles

✍ Scribed by Gautier, B.; Prudon, G.; Dupuy, J. C.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 273 KB
• Volume: 26
• Category: Article
• ISSN: 0142-2421
• DOI: 10.1002/(sici)1096-9918(199812)26:13<974::aid-sia445>3.0.co;2-o

✦ Synopsis

In this paper, the problem of the deconvolution of SIMS depth proÐles is addressed. In particular, the hypotheses that are necessary for the deconvolution to be possible (in the actual state of the art) in the case of the SIMS signal are reviewed. Then, the principle of regularization, which is a mandatory step in the resolution of an ill-posed problem, is clariÐed. Two regularization methods used in the Ðeld of SIMS analysis are compared : Miller regularization and maximum entropy regularization.

In a second part the study of a possible deconvolution, using a depth resolution function (DRF) that is not the DRF that has experimentally convolved the proÐle, is justiÐed and theoretically addressed. Two cases arise : the DRF used in the deconvolution process is either thinner than the experimental DRF or it is thicker. It is shown that deconvolution using a DRF that is wider than the DRF that actually convolved the proÐle is possible, and must be taken into consideration. Some examples of simulated deconvolutions with a false DRF are given, and some tools are proposed that are theoretically able to detect a problem when the DRF used in the deconvolution process is wider than the real DRF.

In the last section, an example of experimental deconvolution shows that the deconvolution process is able to provide reliable information. In particular, deconvolution of a SIMS analysis conducted at 5.5 keV and 42.4Ä O 2 ' incidence (in a Cameca IMS 3/4f) reveals some features of the sample that require at least 1 keV and 60Ä O 2 ' primary beam incidence to be detected experimentally.