Breakdown walkout in AlAs/GaAs HEMTs

Authors :: P.C. Chao
M.Y. Kao
Michael Shur
B.R. Lee
Source :: IEEE Transactions on Electron Devices. 39:738-740
Publication Year :: 1992
Publisher :: Institute of Electrical and Electronics Engineers (IEEE), 1992.
Abstract: 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. >