Characterization and Modeling of Impact Ionization Effects on Small and Large Signal Characteristics of AlGaAs/GaInAs/GaAs PHEMTs

This paper presents an analysis of the impact ionization phenomenon encountered in AlGaAs/GaInAs/GaAs PHEMTs. Two characterizations techniques have been used. At first, pulsed S-parameter measurements in the Impact Ionization (II) region have been required to identify the cut-off frequency of the phenomenon. Then, using these measurements, we propose a new small-signal model taking into account the frequency transition between quasi-static characteristics measured in pulsed conditions and microwave characteristics. Finally, this model has been tested in large signal conditions and the simulation results were checked through Load Pull Time domain Measurements (LPTM) to assert the validity of the model.