SCANNING TUNNELING MICROSCOPE MICROLENS WITH MAGNETIC FOCUSING

被引:11
作者
HORDON, LS
PEASE, RFW
机构
来源
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B | 1990年 / 8卷 / 06期
关键词
D O I
10.1116/1.585140
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
We describe a design for a low-energy scanning tunneling microscope microlens with magnetic focusing, to achieve several improvements over conventional lens systems and previously reported microlens systems. First, scaling of the lens dimensions yields corresponding scaling of spherical and chromatic aberration coefficients. Second, magnetic focusing avoids the difficulty inherent in electrostatic microlenses of withstanding large potential differences over short distances, which can lead to dielectric breakdown in insulating elements of the lens, although magnetic focusing has an analogous problem with maximum achievable fields. Third, a low-energy (100-200 eV) electron beam offers a significant advantage in lithography, where proximity effect and scattering within the resist from conventional high-energy (> 1 keV) electron beam systems act as serious limitations on pattern fidelity. Calculations indicate that for reasonable values of lens parameters (aperture potential = 60-200 V, B(z) = 1.4-2 T, tip radius = 300 angstrom, aperture diameter = 0.25-0.5-mu-m, and convergence semi-angle = 20-100 mrad), aberration coefficients on the order of 40-80-mu-m and beam diameters down to 150 angstrom are obtained, with beam current up to several-mu-A.
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收藏
页码:1686 / 1690
页数:5
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