Kozole Joseph, Willingham David, Winograd Nicholas
Department of Chemistry, Penn State University, University Park, PA 16802, United States.
Appl Surf Sci. 2008 Dec 15;255(14):1068-1070. doi: 10.1016/j.apsusc.2008.05.254.
The effect of incident angle on the quality of SIMS molecular depth profiling using C(60) (+) was investigated. Cholesterol films of ~300 nm thickness on Si were employed as a model and were eroded using 40 keV C(60) (+) at an incident angle of 40° and 73° with respect to the surface normal. The erosion process was characterized by determining at each angle the relative amount of chemical damage, the total sputtering yield of cholesterol molecules, and the interface width between the film and the Si substrate. The results show that there is less molecule damage at an angle of incidence of 73° and that the total sputtering yield is largest at an angle of incidence of 40°. The measurements suggest reduced damage is not necessarily dependent upon enhanced yields and that depositing the incident energy nearer the surface by using glancing angles is most important. The interface width parameter supports this idea by indicating that at the 73° incident angle, C(60) (+) produces a smaller altered layer depth. Overall, the results show that 73° incidence is the better angle for molecular depth profiling using 40 keV C(60) (+).
研究了入射角对使用C(60)(+)进行二次离子质谱分子深度剖析质量的影响。以硅上厚度约为300 nm的胆固醇薄膜为模型，使用40 keV的C(60)(+)以相对于表面法线40°和73°的入射角对其进行侵蚀。通过在每个角度确定化学损伤的相对量、胆固醇分子的总溅射产率以及薄膜与硅衬底之间的界面宽度来表征侵蚀过程。结果表明，在73°入射角时分子损伤较少，而在40°入射角时总溅射产率最大。测量结果表明，损伤减少不一定取决于产率提高，并且通过掠射角使入射能量更靠近表面沉积是最重要的。界面宽度参数通过表明在73°入射角时，C(60)(+)产生的改变层深度较小来支持这一观点。总体而言，结果表明73°入射角是使用40 keV C(60)(+)进行分子深度剖析的更佳角度。
