Total dose radiation hardness of MOS devices in hermetic ceramic packages

The total-dose radiation hardness of hardened MOS transistors is experimentally shown to be degraded by hydrogen gas commonly trapped in hermetic-ceramic-package cavities. This introduces another variable to be considered in the manufacture and hardness assurance of total-dose-hardened integrated circuits. The observation also extends the link between hydrogen and interface-state formation to the understanding of hydrogen's role in ionizing radiation effects. It is concluded from experiments in which hydrogen is diffused into irradiated oxides after Co-60 exposure that the diffusing hydrogen interacts with independently created radiation damage to form interface states.<>