Correlation of depth resolution and preferential sputtering in depth profiles of thin layers by Secondary Ion Mass Spectrometry (SIMS)

• Published in: Thin solid films Vol. 662; pp. 165 - 167
• Main Authors: Hofmann, S., Lian, S.Y., Han, Y.S., Deng, Q.R., Wang, J.Y.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.09.2018
• Subjects: Atomic mixing length; Delta layer; Depth resolution; Preferential sputtering; Preferential sputtering; Depth resolution; Atomic mixing length; Delta layer
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2018.07.045

In high resolution depth profiling of thin layers by Secondary Ion Mass Spectrometry (SIMS), there is a strong influence of preferential sputtering on depth resolution which is frequently overlooked. However, for preponderant atomic mixing, an extended version of the so called Mixing-Roughness-Information depth (MRI) model reveals the correlation between preferential sputtering and atomic mixing. While the latter is constant for a given ion-solid interaction, the effective mixing length scales inversely with the relative sputtering rate on the depth scale and is mainly responsible for the observed changes in profile widths. As an experimental example, recently published results by Moiseeev et al. [1] are re-evaluated and quantified by the MRI model, thus confirming the model prediction for the case of preferential sputtering of GaAs with respect to Mn. •The measured In and Mn SIMS depth profiles were re-evaluated by the MRI model•The fitted MRI parameters are supported by SRIM results•An improved and convincing explanation based on preferential sputtering is presented.