A Simple Model for Predicting Radiation Effects in MOS Devices

A mathematical model for the electrical consequence of charge buildup in metal-oxide-semiconductor devices has been investigated and found to be useful. It can be used (a) for comparing experimental data from different sources and (b) for making predictions of the lifetime of MOS circuits exposed to radiation in space or laboratory environments. A wide range of experimental data has been collected together and is presented in the form of a normalised oxide radiation-sensitivity parameter A, representing the probability of hole capture. The results show that the simple model, based upon a thin sheet of hole traps, must be modified when the rate of interface-state creation is commensurate with the trap filling rate but that this does not destroy its usefulness for a wide range of applications.