Mao Dan, Brenes Daniel A, Lu Caiyan, Wucher Andreas, Winograd Nicholas
Department of Chemistry, Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802.
Surf Interface Anal. 2013 Jan 1;45(1):65-67. doi: 10.1002/sia.5082. Epub 2012 Jul 6.
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and atomic force microscopy (AFM) are employed to characterize a wedge-shaped crater eroded by a 40 keV C(60) (+) cluster ion beam on an organic thin film of 402 nm of barium arachidate (AA) multilayers prepared by the Langmuir-Blodgett (LB) technique. Sample cooling to 90 K was used to help reduce chemical damage, improve depth resolution and maintain constant erosion rate during depth profiling. The film was characterized at 90 K, 135 K, 165 K, 205 K, 265 K and 300 K. It is shown that sample cooling to 205 K or lower helps to inhibit erosion rate decay, whereas at 300 K and 265 K the erosion rate continues to drop after 250 nm of erosion, reaching about half of the initial value after removal of the entire film. Depth profiles are acquired from the SIMS images of the eroded wedge crater. The results suggest that sample cooling only slightly improves the altered layer thickness, but eliminates the decrease in erosion rate observed above 265 K.
采用飞行时间二次离子质谱（TOF-SIMS）和原子力显微镜（AFM）对通过朗缪尔-布洛杰特（LB）技术制备的402 nm厚的花生酸钡（AA）多层有机薄膜上由40 keV C(60) (+) 团簇离子束侵蚀形成的楔形坑进行表征。将样品冷却至90 K有助于减少化学损伤、提高深度分辨率并在深度剖析过程中保持恒定的侵蚀速率。在90 K、135 K、165 K、205 K、265 K和300 K温度下对该薄膜进行了表征。结果表明，将样品冷却至205 K或更低有助于抑制侵蚀速率衰减，而在300 K和265 K时，侵蚀250 nm后侵蚀速率继续下降，去除整个薄膜后达到初始值的约一半。从侵蚀后的楔形坑的SIMS图像获取深度剖析图。结果表明，样品冷却仅略微改善了改变层的厚度，但消除了在265 K以上观察到的侵蚀速率下降。
