一种用于超高真空原子探针场离子显微镜的差分抽运低能离子束系统。

A differentially pumped low-energy ion beam system for an ultrahigh-vacuum atom-probe field-ion microscope.

作者信息

Amano J, Seidman D N

机构信息

Department of Materials Science and Engineering and the Materials Science Center, Bard Hall, Cornell University, Ithaca, New York 14853, USA.

出版信息

Rev Sci Instrum. 1979 Sep;50(9):1125-9. doi: 10.1063/1.1135998.

DOI:10.1063/1.1135998

PMID:18699682

Abstract

An ultrahigh-vacuum (UHV) differentially pumped low-energy (50-3000 eV) ion beam system for the in situ irradiation of specimens in a UHV atom-probe field-ion microscope (FIM) was designed and constructed. The ion beam system consisted of a Finkelstein-type ion source, an Einzel lens, and a magnetic mass analyzer. The ion source was connected to the analyzer chamber by small apertures which resulted in differential pumping between the ion source and the analyzer chamber; during a typical in situ irradiation of a specimen in the atom-probe FIM the total pressure was maintained at approximately 10(-7) Torr. In the case of helium ion irradiation the optimum ion-current density was approximately 0.5 microA cm(-2) for 300-eV He+ ions at the atom-probe FIM specimen. After the completion of a helium ion irradiation the pumpdown time from 5 x 10(-7) to approximately 3 x 10(-10) Torr in the atom-probe FIM chamber was 0.5 h.

摘要

设计并构建了一种超高真空（UHV）差分抽气低能（50 - 3000 eV）离子束系统，用于在超高真空原子探针场离子显微镜（FIM）中对样品进行原位辐照。该离子束系统由一个芬克尔斯坦型离子源、一个单透镜和一个磁质量分析器组成。离子源通过小孔与分析室相连，这导致了离子源和分析室之间的差分抽气；在原子探针FIM中对样品进行典型的原位辐照期间，总压力保持在约10^(-7) 托。在氦离子辐照的情况下，对于原子探针FIM样品上300 eV的He+离子，最佳离子电流密度约为0.5 μA cm^(-2)。氦离子辐照完成后，原子探针FIM腔从5×10^(-7) 托抽至约3×10^(-10) 托的抽气时间为0.5小时。