Prediction of Dose to Failure versus Dose Rate for a Recessed Oxide Digital Bipolar Microcircuit

This paper reports on measurements made of microcircuit performance at different, low dose rates over extended periods of time in an attempt to assess the suitability of using the microcircuit in a satellite mission radiation environment. It was planned to use Fairchild 54F251 parts in a 2.3 rad(Si) per hour satellite environment for a five-year mission in which they would accumulate 100 kilorad(Si). An initial test at 10,000 rad(Si) per hour resulted in values of the input current high, IIH, which greatly exceeded the specified limit of 20¿A after the first radiation exposure level of 10 kilorad(Si). Typically, input currents above 20¿A are considered failures. Subsequent tests at lower dose rates resulted in total doses to failure which were much greater than 10 kilorad(Si), and allowed a prediction of successful operation for the mission duration. The analysis used to predict performance at low mission dose rates is applicable to other part types experiencing similar radiation-induced effects.