I–V anomalies on InAlAs/InGaAs/InP HFETs and deep levels investigations

In this paper, static measurements and defect analysis performed on InAlAs/InGaAs/InP HFETs are presented. Id–Vds–T, Id–Vgs–T and Ig–Vgs–T characteristics show anomalies (leakage current, degradation in saturation current, kink effect, distortions on Id–Vd characteristics in saturation region after high voltage application, …). Deep defects analysis performed by means of capacitance transient spectroscopy (C-DLTS) and frequency dispersion of the output conductance (Gds(f)) prove the presence of deep defects with activation energies ranging from 0.12 to 0.75 eV. The presence of generation–recombination centers, acting like traps, is confirmed by Ig–Vgs. The localization and the identification of these defects are presented. Finally, the correlation between the anomalies observed on output characteristics and defects is discussed.