Breakdown walkout in AlAs/GaAs HEMTs

It was observed that the gate breakdown voltage of an unpassivated AlGaAs/GaAs HEMT can move to higher negative values when a current is allowed to flow through the gate under reverse gate bias voltage. When a reverse bias is applied between the gate and source, this breakdown 'walkout' can be accompanied by a permanent increase in device source resistance and decreases in transconductance and drain saturation current. A similar effect was observed in AlGaAs/InGaAs/GaAs pseudomorphic HEMTs and in GaAs MESFETs. This effect was not observed in silicon nitrided passivated devices.<
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