Focused ion beams with varied exposure dose were used to mill rectangular trenches into PMMA on SiO₂. The dose response was investigated by atomic force microscopy measurements. TRIM calculations were used to simulate the ion distributions and damages expected inside the target. The depth of the trenches measured by AFM showed an unexpected decrease for intermediate dosages of high energetic helium ions in contrast to low energetic helium and nitrogen ions. This has been attributed to the formation of metastable blisters in the PMMA layer.

中文翻译：

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PMMA 中氦气和氮气束的剂量相关铣削效率

使用具有不同曝光剂量的聚焦离子束在 SiO ₂上将矩形沟槽研磨成 PMMA 。通过原子力显微镜测量研究剂量响应。TRIM 计算用于模拟目标内部预期的离子分布和损坏。与低能氦离子和氮离子相比，AFM 测量的沟槽深度显示出中等剂量的高能氦离子意外降低。这归因于在 PMMA 层中形成了亚稳态气泡。