2017年第64回応用物理学会春季学術講演会

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シンポジウム(口頭講演)

シンポジウム » GFIS(電界電離ガスイオン源)ガスイオン顕微鏡技術とその材料・デバイス研究開発への応用:現状と今後の展望

[16p-315-1~11] GFIS(電界電離ガスイオン源)ガスイオン顕微鏡技術とその材料・デバイス研究開発への応用:現状と今後の展望

2017年3月16日(木) 13:15 〜 18:00 315 (315)

水田 博(北陸先端大)、小川 真一(産総研)

17:45 〜 18:00

[16p-315-11] Interaction of gas field ionized nitrogen with silicon

〇(P)Schmidt Marek Edward1、Zhang Xiaobin1、Oshima Yoshifumi1、The Anh Le1、Yasaka Anto2、Kanzaki Teruhisa1、Muruganathan Manoharan1、Akabori Masashi1、Shimoda Tatsuya1、Mizuta Hiroshi1 (1.JAIST、2.Hitachi High-Tech Science Corp.)

キーワード:Nitrogen, Molecular Dynamics

A larger number of gas molecules (among them hydrogen, helium, nitrogen and neon) can be ionized by the gas field ion source (GFIS) and used as projectiles in focused ion beam (FIB) systems. Among them, the nitrogen stands out as it forms a very strong covalent bond. It is not yet fully understood how this N2 molecule behaves during gas field ionization and sample interaction, i.e. if the bond is broken during ionization. The mass spectrum of electron ionized N2 gas shows a small amount of N+ and a larger amount of N2+. Here, we report scanning transmission electron microscopy (STEM) analysis of cross sections extracted from silicon bombarded with gas field ionized N2 molecules with a line dose from 0.24 and 9.5x103 ion/nm. The extracted implantation depths for ion energies of 25 and 16 keV are compared with theoretical values and suggest that the bond sustains the field ionization and is broken during sample interaction. We use first principle molecular dynamics simulation to support this finding (Figure 1b), in particular that the covalent bond is broken within the first few atomic layers of the impinged silicon target.