Evaluation of the trap concentration in highly doped semiconductors from low-frequency noise spectra

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Abstract
Low‐frequency noise measurements were carried out in AlGaAs/GaAs heterostructures. At temperatures between 100 and 300 K the spectra showed superpositions of a 1/f spectrum and two generation‐recombination (g‐r) noise contributions. From the amplitude of the 1/f spectrum Hooge parameters at room temperatures between 1.2 and 2×10−5 were obtained. A model for calculating the trap concentration in these highly doped semiconductors is proposed. This model assumes the location of the g‐r noise within the surface depletion region. The activation energies of the two traps were evaluated to 0.43 and 0.37 eV with corresponding capture cross sections of 2×10−13 and 5×10−14 cm2, respectively. The trap concentrations were evaluated to 2×1017 and 3×1017 cm−3, respectively.