A Radiation Effects Large Signal Equivalent Circuit for MOS Transistors

A large signal equivalent circuit which can be used to predict the behavior of MOS transistors in a pulsed radiation environment is presented. MOS FET behavior is interpreted wholly in terms of standard circuit elements which correspond closely to the operating principles of the device. The channel current is expressed as a single equation of the terminal voltages, which permits direct application of the model to many of the existing TREE computer codes. The model is generalized to encompass n-or p-channel transistors in a manner such that the source and drain terminals are interchangeable. Some aspects of the FET intrinsic time response are as yet unresolved, but a model which neglects the intrinsic time response has been successfully utilized in the SCEPTRE computer program to predict the transient response of a discrete MOS flip-flop circuit.