A technique to characterize oxide charge detrapping in a Fowler–Nordheim stressedn-metal–oxide–semiconductor field effect transistor is proposed. This technique consists of two alternating phases, an oxide charge detrapping phase and a subthreshold current measurement phase. An analytical model relating a subthreshold current transient to oxide charge density and detrapping time constants was derived. By varying the gate bias in the detrapping phase and the ambient temperature, the field and temperature dependences of oxide charge detrapping can be obtained from the subthreshold current transients measured. ©1997 American Institute of Physics.