A 90 nm bulk CMOS radiation hardened by design cache memory

A RHBD high performance cache fabricated on 90 nm bulk CMOS is presented. Test silicon cache data arrays can read and write at 1.02 GHz. Irradiation to 2 Mrad(Si) negligibly impacts standby current. The cache is write-through, and relies on error checking to allow cache invalidation when single event upsets or potential single event transients are detected. The write-through cache architectural state will then naturally be reloaded by the ensuing microprocessor operations. Single cycle invalidation is supported. Single event error ion beam test results are presented, as is a description of measured single event effects in array and peripheral circuits and their mitigation by the design.