The effect of thermal annealing on the properties of Al-AlOx-Al single electron tunneling transistors

The effect of thermal annealing on the properties of Al-AlOx-Al single elec tron tunneling transistors is reported. After treatment of the devices by a nnealing processes in forming gas atmosphere at different temperatures and for different times, distinct and reproducible changes of their resistance and capacitance values were found. According to the temperature regime, we observed different behaviors with regard to the resistance changes, namely the tendency to decrease the resistance by annealing at T=200 degreesC, but to increase the resistance by annealing at T=400 degreesC. We attribute th is behavior to changes in the aluminum oxide barriers of the tunnel junctio ns. The good reproducibility of these effects with respect to the changes o bserved allows the proper annealing treatment to be used for postprocess tu ning of tunnel junction parameters. Also, the influence of the annealing tr eatment on the noise properties of the transistors at low frequency was inv estigated. In no case did the noise figures in the 1/f regime show signific ant changes. (C) 2001 American Institute of Physics.