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In this paper,drain current transient characteristics of β-Ga2O3 high electron mobility transistor (HEMT) are studied to access current collapse and recovery time due to dynamic population and de-population of deep level traps and interface traps.An approximately 10 min,and 1 h of recovery time to steady-state drain current value is measured under 1 ms of stress on the gate and drain electrodes due to iron (Fe)-doped β-Ga2O3 substrate and germanium (Ge)-doped β-Ga2O3 epitaxial layer respectively.On-state current lag is more severe due to widely reported defect trap Ec-0.82 eV over Ec-0.78 eV,-0.75 eV present in Iron (Fe)-doped β-Ga2O3 bulk crystals.A negligible amount of current degradation is observed in the latter case due to the trap level at Ec-0.98 eV.It is found that occupancy of ionized trap density varied mostly under the gate and gate-source area.This investigation of reversible current collapse phenomenon and assessment of recovery time inβ-Ga2O3 HEMT is carried out through 2D device simulations using appropriate velocity and charge transport models.This work can further help in the proper characterization of β-Ga2O3 devices to understand temporary and permanent device degradation.