Low-frequency noise in β-(Al_xGa_1−x)₂O₃ Schottky barrier diodes

We report on the low-frequency electronic noise in β-(Al_xGa_1−x)₂O₃ Schottky barrier diodes. The noise spectral density reveals 1/f dependence, characteristic of the flicker noise, with superimposed Lorentzian bulges at the intermediate current levels (f is the frequency). The normalized noise spectral density in such diodes was determined to be on the order of 10⁻¹² cm²/Hz (f = 10 Hz) at 1 A/cm² current density. At the intermediate current regime, we observed the random telegraph signal noise, correlated with the appearance of Lorentzian bulges in the noise spectrum. The random telegraph signal noise was attributed to the defects near the Schottky barrier. The defects can affect the local electric field and the potential barrier and, correspondingly, impact the electric current. The obtained results help in understanding the noise in Schottky barrier diodes made of ultra-wide bandgap semiconductors and can be used for the material and device quality assessment.