Transient and total dose radiation characteristics of an SOS LSI array

Transient and total dose characteristics of irradiated 300 gate LSI arrays are presented. These arrays are configured to carry out the arithmetic function of an Arithmetic-Logic Unit. Samples were fabricated with ion implanted source-drain regions, wet-or dry-oxide (SiO2) gate insulator, and n⁺deposited polysilicon gates. Irradiation sources were the AFCRL Linac operating with 20- and 100-ns pulses, and the Fort Monmouth Cobalt 60 facility. Transient upset measurements of four worst case outputs are presented with the samples operating in an active and static mode during exposure. Worst case is the static mode of operation during exposure. The upset dose rate during an active mode depends on the time of occurrence of the radiation pulse relative to the transition waveform. Functional failure doses made in-situ are presented for exposure dose rates ranging from 4.2 to 1000 krads (Si)/h. Corresponding total dose failure for these dose rates varies from 10⁵to 10⁶rads (Si). The rapid annealing properties of the gate insulator are responsible for this dependence on dose rate.