Towards reliable X-ray photoelectron spectroscopy: Sputter-damage effects in transition metal borides, carbides, nitrides, and oxides
Towards reliable X-ray photoelectron spectroscopy: Sputter-damage effects in transition metal borides, carbides, nitrides, and oxides
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DOI：
10.1016/j.apsusc.2020.148599
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发表时间：
2021-03-15
影响因子：
6.7
通讯作者：
Hultman, L.
中科院分区：
文献类型：
--
作者：
Greczynski, G.;Hultman, L.
Ar+溅射蚀刻通常在X射线光电子能谱（XPS）分析之前使用，目的是去除表面氧化物和污染物。由于XPS探测深度与离子束改性层的厚度相当，因此来自后者的信号在光谱中占主导地位。我们在这里通过研究单相IVB族过渡金属（IVB-TM）硼化物、碳化物、氮化物和氧化物薄膜样本的离子辐照效应来检查可靠的XPS分析的条件。溅射损伤的程度，表现为表面组成的变化，结合能的变化，峰展宽，和新的光谱特征的出现，材料系统之间的变化很大：从IVB-TM碳化物的情况下的微妙的影响到IVB-TM氧化物的光谱成分的完全变化。决定性因素是：（i）由于受影响层中的离子诱导混合而可能形成的化合物的性质，以及（ii）溅射后的最终元素组成，和（iii）相对于XPS探测深度的受Ar+影响层的厚度。我们的研究结果表明，Ar+离子辐照对XPS谱的影响不能被事先忽略，大量的审查，如果没有限制，是必要的光谱解释。
Ar+ sputter etching is often used prior to X-ray photoelectron spectroscopy (XPS) analyses with the intention to remove surface oxides and contaminants. Since the XPS probing depth is comparable to the thickness of the ionbeam modified layer the signal from the latter dominates the spectra. We check here the conditions for reliable XPS analysis by studying ion irradiation effects for single-phase Group IVB transition metal (IVB-TM) boride, carbide, nitride, and oxide thin film specimens. The extent of sputter damage, manifested by changes in the surface composition, binding energy shift, peak broadening, and the appearance of new spectral features, varies greatly between material systems: from subtle effects in the case of IVB-TM carbides to a complete change of spectral components for IVB-TM oxides. The determining factors are: (i) the nature of compounds that may form as a result of ion-induced mixing in the affected layer together with (ii) the final elemental composition after sputtering, and (iii) the thickness of the Ar+-affected layer with respect to the XPS probing depth. Our results reveal that the effects of Ar+ ion irradiation on XPS spectra cannot be a priori neglected and a great deal of scrutiny, if not restraint, is necessary during spectra interpretation.