Evolution of LF noise in power PHEMT's submitted to RF and DC step stresses

DC and RF step stresses have been performed under different bias conditions on a power amplifier using a double heterojunction AlGaAs/InGaAs/AlGaAs PH EMT. After DC or RF life tests, no drastic evolution of DC electrical param eters is observed, The DC step stresses induces an increase of the gate cur rent noise spectral intensity, which is more pronounced for devices biased under pinch-off conditions than under open channel conditions. In correlati on, drain current transient spectroscopy has revealed the contribution of e lectron emission traps located in the vicinity of the gate. The RF step str esses and the DC step stresses performed under pinch-off conditions induce an increase of the drain current noise that suggests degradation of electro n transport properties in the channel. (C) 2001 Elsevier Science Ltd. All r ights reserved.