CMOS/SOS 4K RAMs Hardened to 100 Krads(Si)

Two CMOS/SOS 4K memories were fabricated with a recently developed, hardened SOS process. Memory functionality after radiation doses well in excess of 100 Krads(Si) was demonstrated. The critical device processing steps were identified. The radiation-induced failure mode of the memories is understood in terms of the circuit organization and the radiation behavior of the individual transistors in the memories.