High total dose effects on CMOS/SOI technology

CMOS silicon-on-insulator (SOI) technology has shown its ability to process hardened components which remain functional after irradiation with a total dose of several tens of megarads. New tests on elementary transistors and the 29101 microprocessor have been made at doses up to 100 Mrad(SiO/sub 2/) and above. Results of irradiation at these total doses are presented for different biases, together with the post-irradiation behavior of the components. All the observations show that new parameters must be taken into account for hardness assurance at a high level of total dose. This study has shed light on some of the data required to understand the underlying physics and which must be taken into account to provide hardness assurance: in particular, the variation of the threshold voltage shift with the gate length, the recovery phenomena after a very high dose irradiation, and the influence of the dynamic bias on the hardness. >