open access

https://hdl.handle.net/2115/67013

Quantitative analysis of helium by post-ionization method using femtosecond laser technique

英語

quantitative analysis

2016-11

Wiley-Blackwell

Surface and interface analysis

48(11)

1181-1184

Helium has the largest ionization potential of all elements; thus, it is difficult to ionize for measurement by mass spectrometry. In order to analyze He, a tunnel-ionization time-of-flight sputtered neutral mass spectrometry system (called LIMAS) has recently been developed. LIMAS uses a femtosecond laser technique and can ionize He. We quantified the effectiveness of this method for He analysis from a 2.5x4 mu m(2) area of He-implanted silicon. The amount of He in an implant was quantified by measuring the ion current, giving a nominal implant fluence per unit area. Thus, the fraction of total He measured by LIMAS during depth profiling could be quantified by comparison with the He concentration of the reference implant. The He+ intensities normalized by host ions of Si linearly correlated with the known He concentrations with a reproducibility of 10% at concentrations less than 10(21)cm(-3). The detection limit was down to 10(18) He cm(-3) (20ppm). For concentrations exceeding 10(21)cm(-3), the He intensities are smaller than those expected from the lower concentration range. This non-linearity may reflect the limit of retention of He in the Si lattice, because He is chemically inert. Copyright (c) 2016 John Wiley & Sons, Ltd.

学術雑誌論文

Accepted Manuscript

This is the peer reviewed version of the following article: Yurimoto, H., Bajo, K., Sakaguchi, I., Suzuki, T. T., Jurewicz, A. J. G., Itose, S., Uchino, K., and Ishihara, M. (2016) Quantitative analysis of helium by post-ionization method using femtosecond laser technique. Surf. Interface Anal., 48: 1181–1184, which has been published in final form at doi:10.1002/sia.6119. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

0142-2421