| 摘要 |
PURPOSE:To allow obtaining high reliability as well as good voltage-current characteristic, by forming the lower electrode of a Josephson junction element in the structure of a double layer thin film with an Nb thin film for the lower layer and NbN thin film for the upper layer. CONSTITUTION:The lower electrode is constituted in the double layer of the Nb thin film 1 and NbN thin film 1 with an insulating layer 2 and upper electrode 3 formed on the NbN thin film 1'. A tunnel junction is formed between the NbN thin film 1' and upper electrode 3 wherein NbN is less subject to surface damage in a manufacturing process to obtain a Josephson junction element with good voltage-current characteristic for tunnel characteristic reflected by the excellent surface stability of the NbN surface layer 1'. Simultaneously, since the Nb thin film as the lower layer is short in the length for flux invasion, kinematic inductance is reduced in contribution. Thus, the constitution is available for a Josephson junction circuit with high magnetic field sensitivity and less wiring delay. |
