Design of a microfabricated, two-electrode phase-contrast element suitable for electron microscopy
Design of a microfabricated, two-electrode phase-contrast element suitable for electron microscopy
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DOI：
10.1016/j.ultramic.2006.09.001
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发表时间：
2007-04-01
期刊：
影响因子：
2.2
通讯作者：
Jin, Jian
中科院分区：
文献类型：
--
作者：
Cambie, Rossana;Downing, Kenneth H.;Jin, Jian
设计了一种微型静电元件，对物镜后焦面上的未散射光束选择性地施加90度相移，以实现电子显微镜中的Zernike型聚焦位相衬度。该设计包括一个圆柱形的偏置电压电极，它周围有一个同心接地电极。利用静电计算确定，只要电极长度与横向特征尺寸之比大于5：1，散射电子束区域的边缘场就会引起微不足道的相移。与Boersch最初提出的用于相同目的的平面三电极Einzel透镜不同，这种新设计不需要绝缘层来分隔偏置电极和接地电极，因此可以通过非常简单的微加工工艺来制造。扫描电子显微镜图像证实，可以很容易地制造具有类似1微米特征尺寸的机械坚固的器件。初步的实验图像表明，正如预期的那样，这些设备确实在散射和未散射的电子之间应用了90度的相移。(C)2006爱思唯尔B.V.保留所有权利。
A miniature electrostatic element has been designed to selectively apply a 90 degrees phase shift to the Unscattered beam in the back focal plane of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. The design involves a cylindrically shaped, biased-voltage electrode, which is surrounded by a concentric grounded electrode. Electrostatic calculations have been used to determine that the fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature size is greater than 5:1. Unlike the planar, three-electrode einzel lens originally proposed by Boersch for the same purpose, this new design does not require insulating layers to separate the biased and grounded electrodes, and it can thus be produced by a very simple inicrofabrication process. Scanning electron microscope images confirm that mechanically robust devices with feature sizes of similar to 1 mu m can be easily fabricated. Preliminary experimental images demonstrate that these devices do apply a 90 degrees phase shift between the scattered and unscattered electrons, as expected. (c) 2006 Elsevier B.V. All rights reserved.