以聚焦離子束技術製備約瑟芬收縮結

The fabrication of Josephson constrict junction by using focused ion beam technology

羅嘉暐(Chia-Wei Lo)

指導教授 ： 陳正中

國立清華大學/理學院/物理學系/碩士(2020年)

摘要

本論文的目的是利用聚焦離子束技術加工出約瑟芬收縮結。我們製作出具有SQUID或SET架構的樣品，利用SQUID結構調控磁通量，進而影響樣品超導電子波函數相位差；利用SET結構觀測以此技術是否能製作出具有充電能量的結構。
在製程上以聚焦離子束技術製作了長度落在18-54 nm、寬度落在 11-31nm的收縮處。實驗數據顯示並無形成量子點接觸，樣品表現出類似約瑟芬結的特性，臨界電流在 40 -179 μA間，對應的約瑟芬能量EJ≅82 367 meV；樣品也表現出類似庫侖阻塞的特性，充電能量EC≅1.8 meV。
我們認為以聚焦離子束技術加工收縮結，能製作出具有EJ、EC的結構。而在未來的工作上可以提升製程精度以製作出量子點接觸。

關鍵字

聚焦離子束 ； 約瑟芬收縮結 ； 約瑟芬結

並列摘要

In this work, we attempt to fabricate Josephson constrict junction by using focused ion beam technology. We fabricated samples with SQUID or SET architecture, and used the SQUID structure to control the magnetic flux, thereby affecting the phase difference of superconducting electric wave function; using the SET structure to observe whether this technology can create a structure with charging energy.
We fabricated constrict junctions with a length of 18-54nm and a width of 11-31nm.The measured data show that the samples does not form a quantum point contact. The samples exhibit Josephson-like behavior. The critical current is between 40-179 μA,corresponding to the Josephson energy E_J of about 82-367 meV. The samples also exhibit Coulomb blockade-like behavior, and the charging energy E_C of about 1.8 meV.
We believe that the Josephson constrict junction is processed by focused ion beam technology can fabricate structures with E_J and E_C.For future works, the precision of the fabrication can be improved to fabricate quantum point contact.

並列關鍵字

focused ion beam ； FIB ； josephson junction ； josephson constrict junction

參考文獻

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