Focused ion beam scan routine, dwell time and dose optimizations for submicrometre period planar photonic crystal components and stamps in silicon
Focused ion beam scan routine, dwell time and dose optimizations for submicrometre period planar photonic crystal components and stamps in silicon
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DOI：
10.1088/0957-4484/18/19/195305
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发表时间：
2007-05-16
期刊：
影响因子：
3.5
通讯作者：
de Ridder, Rene M.
中科院分区：
文献类型：
--
作者：
Hopman, Wico C. L.;Ay, Feridun;de Ridder, Rene M.
聚焦离子束 (FIB) 铣削在硅 (Si) 纳米结构方面受到越来越多的关注。例如，这些结构可用于绝缘体上硅 (SOI) 配置中的光子晶体结构，或用于与压印技术结合具有各种应用的模具。然而，由于硅中的再沉积效应，具有完全垂直侧壁的亚微米孔的 FIB 制造仍然具有挑战性。在本研究中，我们展示了如何将离子束的扫描程序用作侧壁优化参数。实验已在 Si 和 SOI 中进行。此外，我们还表明，使用螺旋扫描方法，硅膜的侧壁角度可以小至 1.5 度。我们通过研究晶体中单孔和多孔的铣削，研究了剂量、环数和停留时间对侧壁角度、孔间铣削和总铣削深度的影响。我们表明，当施加较大剂量时，（体）Si 和 SOI 的侧壁角度可以小至 5 度。最后，我们发现相对较大的停留时间（1 ms）和较小的循环次数有利于获得垂直侧壁。通过将结果与其他人获得的结果进行比较，我们得出结论，每孔固定剂量下的循环次数是决定侧壁角度的参数，而不是停留时间本身。
Focused ion beam ( FIB) milling is receiving increasing attention for nanostructuring in silicon ( Si). These structures can for example be used for photonic crystal structures in a silicon-on-insulator (SOI) configuration or for moulds which can have various applications in combination with imprint technologies. However, FIB fabrication of submicrometre holes having perfectly vertical sidewalls is still challenging due to the redeposition effect in Si. In this study we show how the scan routine of the ion beam can be used as a sidewall optimization parameter. The experiments have been performed in Si and SOI. Furthermore, we show that sidewall angles as small as 1.5 degrees are possible in Si membranes using a spiral scan method. We investigate the effect of the dose, loop number and dwell time on the sidewall angle, interhole milling and total milling depth by studying the milling of single and multiple holes into a crystal. We show that the sidewall angles can be as small as 5 degrees in ( bulk) Si and SOI when applying a larger dose. Finally, we found that a relatively large dwell time of 1 ms and a small loop number is favourable for obtaining vertical sidewalls. By comparing the results with those obtained by others, we conclude that the number of loops at a fixed dose per hole is the parameter that determines the sidewall angle and not the dwell time by itself.