A Transient Two-Tone RF Method for the Characterization of Electron Trapping Capture and Emission Dynamics in GaN HEMTs

In this paper we propose an experimental method for the characterization and extraction of the time constants associated with the charge capture and emission processes of electron-trapping phenomena observed in radio-frequency (RF) power amplifiers (PAs) based on high-electron-mobility transistors (HEMTs). The method consists in the measurement of the transient response of a GaN HEMT-based PA to a series of large-signal two-tone RF excitations with increasing frequency separation, and the successive tracking of the gradual self-biasing experienced by the PA. With little requirements in terms of instrumentation and with applicability to fully assembled PAs, this simple method provides meaningful information on the dynamics of electron trapping close to the actual operating conditions of a GaN HEMT-based PA.