MAPPING CMOS RADIATION TOLERANCE DATA ON A 4-LANE CHART

An analysis is made of the growth of threshold voltage as a function o f radiation dose in a very wide range of Complementary Metal-Oxide Sem iconductor (CMOS) devices, all the way from low (kilorad) to very high (gigarad) doses. It is found that such results can be organized into four LANES OR CORRIDORS on the growth curve diagram. The resulting FOU R-LANE CLASSIFICATION is useful in selecting CMOS technologies and off ers a new terminology for describing the radiation tolerance of ICs, n amely ''Old Soft, New Soft, Tolerant and Very Tolerant''. The form of the lanes, though arrived at empirically, is consistent with the curre nt theory of radiation response of MOS structures. The position of a d evice test result in this framework is a useful indication of the suit ability of a device for use in a given radiation environment and could form the basis of a ''league table'', used to assess the performance of ''hardening laboratories'' around the world and as a reference sour ce for the properties of thin-film oxide materials.