This paper describes the characterization of the hot carrier-induced interface traps by a forward gated-diode measurement in an N-channel MOSFET/SOI.The experimental results achieved by this method show that the R-G current peak can directly give stress-induced average interface trap density so to characterize the device's hot carrier degradation behavior and evaluate the quality of SOI wafer.As expected,a power law of ΔN_it~t^0.787 between the stress-induced interface trap density and accumulated stressed time has been obtained.