LAUSR

The electrical stress-induced increase in forward and reverse leakage current has been commonly observed in beta-gallium oxide ( $\beta $ -Ga2O3) Schottky barrier diodes (SBDs). However, the transformation of the current transport mechanism during stress has not been investigated. Its correlation with defects in the devices has also not been established. In this work, the transformation of the current transport mechanism and the defect behavior for $\beta $ -Ga2O3 SBDs during constant forward bias stress are investigated by the temperature-dependent current–voltage ( ${I}$ – ${V}$ – ${T}{)}$ and deep-level transient spectroscopy (DLTS) techniques, respectively. For the forward leakage current, the predominant transport mechanism transforms from thermionic emission (TE) to trap-assisted tunneling (TAT) after stress. The enhancement of TAT after stress is derived from a shorter tunneling path, which can be attributed to the generation of a shallow-level defect ( ${E}_{C}$ -0.2 eV), while for the reverse leakage current transport mechanism, the predominant transport mechanism transforms from Poole–Frenkel (PF) emission to TAT after stress. The ionization of newly generated shallow donors narrows the depletion region and reduces the distance of tunneling, which makes the carriers more likely to tunnel assisted by the defects in the stressed devices than thermally emitted.