Single Event Upset Rate Estimates for a 16-K CMOS SRAM

A radiation-hardened 16-K CMOS SRAM has been developed for satellite and deep space applications. The RAM memory cell was modeled to predict the critical charge, necessary for single-particle upset, as a function of temperature, total dose, and hardening feedback resistance. Laboratory measurements of the single event cross section and effective funnel length were made using the Lawrence Berkeley Laboratory\´s 88-inch cyclotron to generate high energy krypton ions. The combination of modeled and measured parameters permitted estimation of the upset rate for the ramcell, and the mean-time-to-failure for a 512-K word, 22-bit memory system employing error detection and correction circuits while functioning in the Adam\´s " 90% worst case" cosmic ray environment. This paper is presented in the form of a tutorial review, summarizing the results of substantial research efforts within the single event community.