Recovery of low temperature electron trapping in AlGaAs/InGaAs PM-HEMTs due to impact-ionization

The dc behavior of AlGaAs/InGaAs PM-HEMTs has been Investigated at a low temperature. Two different failure modes have been identified according to bias conditions, consisting of: (a) a dramatic collapse in the drain current I/sub D/, and (b) a considerable shift in the threshold voltage V/sub T/. I/sub D/ decrease is due to trapping of electrons in deep levels in the gate-drain region, while trapping under the gate is responsible for V/sub T/ shift. At high V/sub DS/ a recovery of the dc device characteristics is observed, due to impact-ionization phenomena.<
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