Tunneling Current through Si Donor Level in GaAs/AlAs Single-Barrier Diodes

概要

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The tunneling current in Si planar-doped GaAs/AlAs single-barrier diodes is studied. First, we determine the effects of growth interruption and doped Si impurities on the tunneling current. We observe excess current for a sample with Si doping during growth interruption (Si planar doping) in the AlAs barrier, while we do not observe it for a sample which was subjected only to growth interruption. This result shows that the excess current is not caused by impurities incorporated from the background during growth interruption but by the intentional doping of Si impurities. We then examine the dependence of the excess current on Si concentration. The excess current increases as the Si concentration increases. This result provides further evidence that Si impurities introduce paths for the flow of the excess current. In the conductance–voltage characteristics, we observe a peak corresponding to the excess current. This peak suggests that the excess current flows through zero-dimensional states. Finally, we discuss the Si donor levels as possible origins of the excess current. The shallow donor level is probably responsible for the excess current.
Publication Office, Japanese Journal of Applied Physics, Faculty of Science, University of Tokyoの論文
1997-07-15