Influence of deep levels in AlInAs/GalnAs/InP HFETs

The aim of this work is to show how some parasitic phenomena such as kink effect or low frequency noise often observed in the characteristics of AlInAs/GaInAs/InP composite channel HFETs can be correlated with deep levels. HFETs have been characterized using deep level transient spectroscopy (DLTS), current transient spectroscopy (CTS), drain lag (DL), and low frequency noise (LFN) measurements. Output characteristics of the devices have also been recorded under monochromatic optical excitation in order to study the optical properties of the defects. The main trap is related to the AlInAs layers and identified as E3. It is shown that E3 is responsible for a strong generation-recombination noise at room temperature. This trap also contributes to a strong output conductance variation.