Deep levels and low-frequency noise in AlGaAs∕GaAs heterostructures

Abstract

The low-frequency noise is studied in different AlGaAs∕GaAs heterostructures under electric biases as a function of the temperature. The heterostructures differ in the two-dimensional electron-gas density and the mobility. In addition to the thermal noise, different contributions are found and characterized (1∕f and generation-recombination noises). The presence of the generation-recombination noise is linked to defects in the interface between the channel and electrical contacts. Thermal activation energy values are deduced from Arrhenius plots and related to AsGa antisite defects and DX centers. The 1∕f noise is also characterized and its origin is identified as being the carrier mobility fluctuation dominated by lattice phonons.