| 摘要 |
A method of making Josephson junction devices which minimises the risks of contamination of the tunnelling barrier layer by impurities.
<??>In the method of the invention a first superconductive layer (1) is deposited on a substrate (2), a barrier layer (3) is deposited on the layer (1), and a second superconductive layer is deposited on the barrier layer. A photoresist area (4) corresponding to the window defining the active area of the device is formed on the superconductive layer (5), and the layer (5), and optionally part also of the barrier layer (3), are then oxidised, preferably by an anodising process.
<??>After removal of the photoresist (4) the unchanged superconductive layer (5) protected by the photoresist defines the active window of the device and the oxidised surrounding regions of the layers form an insulating barrier. The device is completed by the addition of other conducting and insulating layers as may be required.
<??>Preferably, the superconductive layers are of niobium or niobium nitride and the tunnelling barrier layer may be of hydrogenated amorphous silicon, germanium, or silicon-germanium alloy.
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