Muramoto Shin, Brison Jeremy, Castner David
University of Washington, Department of Chemical Engineering.
Surf Interface Anal. 2011 Jan;43(1-2):58-61. doi: 10.1002/sia.3479.
In static secondary ion mass spectrometry (SIMS) experiments, an analysis dose of 10(12) ions/cm(2) typically produces optimum results. However, the same dose used in dual beam depth profiling can significantly degrade the signal. This is because during each analysis cycle a high-energy beam is rastered across the same x-y location on the sample. If a sufficient amount of sample is not removed during each sputter cycle, the subsequent analysis cycle will sample a volume degraded by the previous analysis cycles. The dimensionless parameter R' is used to relate the amount of damage accumulated in the sample to the amount of analysis beam dose used relative to the etching beam. Depth profiles from trehalose films spin-cast onto silicon wafers acquired using Bi(1) (+) and Bi(3) (+) analysis beams were compared. As R' increased, the depth profile and the depth resolution (interface width) both degraded. At R' values below 0.04 for both Bi(1) (+) and Bi(3) (+), the shape of the profile as well as the depth resolution (9 nm) indicated that dual beam analysis can be superior to C(60) single beam depth profiling.
在静态二次离子质谱（SIMS）实验中，10¹²离子/厘米²的分析剂量通常能产生最佳结果。然而，在双束深度剖析中使用相同剂量会显著降低信号。这是因为在每个分析周期中，高能束会在样品上的同一x - y位置进行光栅扫描。如果在每个溅射周期中没有去除足够量的样品，后续的分析周期将对被先前分析周期降解的体积进行采样。无量纲参数R'用于将样品中积累的损伤量与相对于蚀刻束使用的分析束剂量相关联。比较了使用Bi(1)⁺和Bi(3)⁺分析束获取的旋涂在硅片上的海藻糖薄膜的深度剖析。随着R'增加，深度剖析和深度分辨率（界面宽度）均下降。对于Bi(1)⁺和Bi(3)⁺，当R'值低于0.04时，剖析曲线的形状以及深度分辨率（9纳米）表明双束分析可能优于C60单束深度剖析。
