A method for operating a field-effect transistor having a source terminal, a drain terminal, a gate terminal, a drift region and a dielectric region adjoining the drift region, is provided. The method includes: connecting at least one of the drain terminal and the source terminal to a load; applying a sequence of voltage pulses between the gate terminal and the source terminal to repetitively switch the field-effect transistor such that the field-effect transistor is driven in an avalanche mode between the voltage pulses, during the avalanche mode avalanche multiplication occurring in the drift region close to the dielectric region; and applying at least one relaxation pulse to the field-effect transistor to reduce an accumulation of charges in the dielectric region due to hot charge carriers generated in the avalanche mode. Further, a field-effect transistor and a circuit configuration including the field-effect transistor are provided.