Bias and temperature dependence of the noise in a single electron transistor
Microelectronics and Nanoscience, Applied Solid State
Göteborgs Universitet/Chalmers Tekniska Högskola
AB, 41296 Göteborg, Sweden
Published online: 15 April 1999
A single electron transistor based on Al-AlOx-Nb tunnel junctions was fabricated by shadow evaporation and in situ barrier formation. Its output current noise was measured, using a transimpedance amplifier setup, as a function of bias voltage, gain, and temperature, in the frequency range (1-300) Hz. The spot noise at 10 Hz is dominated by a gain dependent component, indicating that the main noise contribution comes from fluctuations at the input of the transistor. Deviations from ideal input charge noise behaviour are found in the form of a bias dependence of the differential charge equivalent noise, i.e. the derivative of current noise with respect to gain. The temperature dependence of this effect could indicate that heating is activating the noise sources, and that they are located inside or in the near vicinity of the junctions.
PACS: 73.23.Hk – Coulomb blockade; single-electron tunneling / 73.40.Rw – Metal-insulator-metal structures
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999