Barac Marko, Brajković Marko, Bogdanović Radović Iva, Kovač Janez, Siketić Zdravko
Ruđer Bošković Institute, Bijenička c. 54, HR-10000 Zagreb, Croatia.
Jožef Stefan International Postgraduate School, Jamova c. 39, SLO-1000 Ljubljana, Slovenia.
J Am Soc Mass Spectrom. 2021 Mar 3;32(3):825-831. doi: 10.1021/jasms.1c00006. Epub 2021 Feb 22.
The low energy range (a few 100 keV to a few megaelectronvolts) primary ion mode in MeV secondary ion mass spectrometry (MeV SIMS) and its potential in exploiting the capabilities of conventional (keV) SIMS and MeV SIMS simultaneously were investigated. The aim is to see if in this energy range of both types of materials, inorganic and organic, can be simultaneously analyzed. A feasibility study was conducted, first by analyzing the dependence of secondary ion yields in indium tin oxide (ITO, InOSn) and leucine (CHNO) on various primary ion energies and charge states of a Cu beam, within the scope of equal influence of electronic and nuclear stopping. Expected behavior was observed for both targets (mainly nuclear sputtering for ITO and electronic sputtering for leucine). MeV SIMS images of samples containing separate regions of Cr and leucine were obtained using both keV and MeV primary ions. On the basis of the image contrast and measured data, the benefit of a low energy beam is demonstrated by Cr intensity leveling with leucine [M + H] intensity, as opposed to a significant contrast at a higher energy. It is estimated that, by lowering the energy, the leucine [M + H] yield efficiency lowers roughly 20 times as a price for gaining about 10 times larger efficiency of Cr yield, while the leucine [M + H] yield still remains sufficiently pronounced.
研究了兆电子伏特二次离子质谱（MeV SIMS）中的低能量范围（几百千电子伏特到几兆电子伏特）初级离子模式及其同时发挥传统（keV）SIMS和MeV SIMS功能的潜力。目的是查看在这个能量范围内，无机和有机这两种类型的材料是否都能被同时分析。进行了一项可行性研究，首先在电子阻止和核阻止的同等影响范围内，分析了氧化铟锡（ITO，InOSn）和亮氨酸（CHNO）中二次离子产率对铜束各种初级离子能量和电荷态的依赖性。在两个靶材上都观察到了预期的行为（ITO主要是核溅射，亮氨酸主要是电子溅射）。使用keV和MeV初级离子获得了包含铬和亮氨酸单独区域的样品的MeV SIMS图像。基于图像对比度和测量数据，与较高能量下的显著对比度相反，通过铬强度与亮氨酸[M + H]强度的平衡，证明了低能量束的优势。据估计，通过降低能量，亮氨酸[M + H]的产率效率大约降低20倍，作为获得约10倍更高铬产率效率的代价，而亮氨酸[M + H]的产率仍然足够显著。
