Ekar Jernej, Kovač Janez
Jožef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.
Jožef Stefan International Postgraduate School, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.
Langmuir. 2022 Oct 25;38(42):12871-12880. doi: 10.1021/acs.langmuir.2c01837. Epub 2022 Oct 14.
The influence of H flooding on the development of surface roughness during time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiling was studied to evaluate the different aspects of a H atmosphere in comparison to an ultrahigh vacuum (UHV) environment. Multilayer samples, consisting of different combinations of metal, metal oxide, and alloy layers of different elements, were bombarded with 1 and 2 keV Cs ion beams in UHV and a H atmosphere of 7 × 10 mbar. The surface roughness was measured with atomic force microscopy (AFM) on the initial surface and in the craters formed while sputtering, either in the middle of the layers or at the interfaces. We found that the roughness after Cs sputtering depends on the chemical composition/structure of the individual layers, and it increases with the sputtering depth. However, the increase in the roughness was, in specific cases, approximately a few tens of percent lower when sputtering in the H atmosphere compared to the UHV. In the other cases, the average surface roughness was generally still lower when H flooding was applied, but the differences were statistically insignificant. Additionally, we observed that for the initially rough surfaces with an of about 5 nm, sputtering with the 1 keV Cs beam might have a smoothing effect, thereby reducing the initial roughness. Our observations also indicate that Cs sputtering with ion energies of 1 and 2 keV has a similar effect on roughness development, except for the cases with initially very smooth samples. The results show the beneficial effect of H flooding on surface roughness development during the ToF-SIMS depth profiling in addition to a reduction of the matrix effect and an improved identification of thin layers.
研究了在飞行时间二次离子质谱（ToF-SIMS）深度剖析过程中，H 气注入对表面粗糙度发展的影响，以评估与超高真空（UHV）环境相比，H 气氛的不同方面。由不同元素的金属、金属氧化物和合金层的不同组合组成的多层样品，在超高真空和 7×10 mbar 的 H 气氛中，用 1 keV 和 2 keV 的 Cs 离子束进行轰击。使用原子力显微镜（AFM）在初始表面以及溅射过程中形成的坑中测量表面粗糙度，这些坑位于层的中间或界面处。我们发现，Cs 溅射后的粗糙度取决于各层的化学成分/结构，并且随着溅射深度的增加而增大。然而，在特定情况下，与超高真空相比，在 H 气氛中溅射时粗糙度的增加大约低几十%。在其他情况下，施加 H 气注入时平均表面粗糙度通常仍然较低，但差异在统计学上不显著。此外，我们观察到，对于初始粗糙度约为 5 nm 的粗糙表面，用 1 keV 的 Cs 离子束溅射可能具有平滑效果，从而降低初始粗糙度。我们的观察结果还表明，除了初始非常光滑的样品外，1 keV 和 2 keV 离子能量的 Cs 溅射对粗糙度发展具有相似的影响。结果表明，H 气注入除了能降低基体效应和改善薄层识别外，还对 ToF-SIMS 深度剖析过程中的表面粗糙度发展具有有益作用。
