ABSTRACT
Breakdown mechanism of focused-ion-beam-implantation-isolalions (FIBII's) in a GaAs/AlGaAs heterostructure is systematically studied. The breakdown current-voltage (I-V) characteristics of the FIBII's display the composite of three bias regimes where the current shows three different functional dependences on the bias voltage. The I-V characteristics in those regimes are quantitatively explained by the models of hopping, thermionic emission, and space-charge-limited injection, respectively. Important parameters such as the charged defect density or the barrier height can be obtained from the I-V characteristics.
