Static TOF-SIMS. A VAMAS interlaboratory study. Part II - accuracy of the mass scale and G-SIMS compatibility

An interlaboratory study involving 32 time-of-flight static SIMS instruments from 13 countries has been conducted. In Part I of the analysis of data, we showed that 84% of instruments have excellent repeatabilities of better than 1.9% and that a relative instrument spectral response (RISR) can be used to evaluate variations between different generic types of instrument. Use of the RISR improves comparability between instruments by a factor of 33. Here, in Part 11, we study the accuracy of the mass scale calibration in TOF-SIMS and evaluate instrument compatibility with G-SIMS. We show that the accuracy of calibration of the mass scale is much poorer than generally expected (-60 ppm for peaks <200 u and -150 ppm for a large molecular peak at 647 u). This is a major issue for analysts. Elsewhere, we have developed a detailed study of the factors affecting the mass calibration and have developed a generic protocol that improves accuracy by a factor of 5. Here, this framework of understanding is used to interpret the results presented. Furthermore, we show that eight out of the ten participants submitting data for G-SIMS could use operating conditions that generated G-SIMS spectra of the PC reference material. This demonstrates that G-SIMS may be conducted with a wide variety of instrument designs. (C) Crown copyright 2007. Reproduced by permission of the Controller of HMSO. Published by John Wiley & Sons, Ltd.