Neutron induced ionization damage in MOS capacitor and MOSFET structures

Abstract

Neutron induced ionisation damage in MOS capacitor and MOSFET structures has been studied As neutron radiation processes are always accompanied by gamma radiation, which produces damage on its own, it is necessary to account for the damage produced by the accompanying gamma rays from neutron radiation. Therefore, devices were subjected to neutron radiation in a swimming pool type of reactor and other samples from the same batch were exposed to an equivalent accompanying gamma radiation using a Co-60 source. The difference in the damage observed was used to characterize the damage due to neutrons alone. It is observed that neutrons, even though uncharged, are capable of causing ionisation damage in the gate oxide which is significant when the radiation is performed under biased conditions. It is believed that neutron induced ionization damage is essentially due to secondary process of recoils.