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Critical Characteristics of Superconducting Thin Films Modified by an Atomic Force Microscope

Hyeong-Gon Kang 1Kwang-Yeop Jahng 1Seokcheol Ko 2Haeseong Lee 3Sung-Hun Lim Byoung-Sung Han 2

1. Chonbuk National University, Basic Science Research Institute, 664-14, Duckjin-Dong 1Ga, Jeonju 561-756, Korea, South
2. Chonbuk National University, Division of Electronics and Information Engineering, 664-14, Duckjin-Dong 1Ga, Jeonju 561-756, Korea, South
3. Korea Basic Science Institute, Jeonju Branch, 664-14, Duckjin-Dong 1Ga, Jeonju 561-756, Korea, South


An atomic force microscope (AFM) has played a key role in nanotechnology as not only a microscopic tool but also a fabricating tool. In this study the AFM was used in fabricating a superconducting flux flow transistor(SFFT) and characterizing the structure of the fabricated transistor. The SFFT is composed of a control line for producing the magnetic field and a body line with a channel. An applied current in the control line controls the critical current density of the body line and generates a voltage over the critical current density. The surfaces of superconducting thin films were modified in order to control the superconducting flux flow using the AFM lithography. This technique is a mask-less process and an effective method to overcome the difficulties in fabricating a nano size channel when a conventional lithography is applied. Superconducting stripes were patterned on LaAl2O3 substrates by the conventional lithography method. The center of the stripe was selectively oxidized by an AFM probe in the presence of the electric field between the probe and the stripe. Then the oxidized surface was analyzed by the AFM image and the critical current density was measured later on. The roughness increased with the number of scanning and an applied voltage, which means that the critical characteristics of superconducting thin films can be controlled by AFM oxidation process. This study reveals that the AFM technique exhibits its capability to fabricate the superconducting flux flow transistors with nano-channel.


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Presentation: poster at E-MRS Fall Meeting 2004, Symposium E, by Hyeong-Gon Kang
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-30 08:47
Revised:   2009-06-08 12:55