PREPARATION OF SELF-ALIGNED IN-LINE TUNNEL-JUNCTIONS FOR APPLICATIONS IN SINGLE-CHARGE ELECTRONICS

The self-aligned in-line technique has been applied to the preparation of ultrasmall low-capacitance metallic tunnel junctions. By using e-beam Lithography the area of AL/AIO(x)/Al contacts has so far been reduced to less than 0.005 mu m(2). At low temperatures high-ohmic double junctions with a small metallic island between them show the Coulomb blockade effect. The current through such a device could be modulated by a voltage applied to a gate electrode capacitively coupled to the island (single-electron transistor). Both single-charge phenomena have been observed at temperatures up to 1 K. (C) 1995 American Institute of Physics.