Radiation Analysis on Spin Transfer Torque Random Access Memory and Design of a Radiation Hardened Sense Circuit

Spin transfer torque (STT-RAM) is a fast, scalable and non-volatile memory technology. These characteristics make STT-RAM one of the best candidates among memories that can be used for space applications. However, understanding of radiation effects on memory cells and the related circuitry is necessary to avoid failure in a high radiation environment. Energetic gamma and neutron particles may strike on sensitive circuit nodes and induce a current by electron/hole pair generation. Radiation induced current potentially leads to read/write failures. In this work, we analyzed the effect of radiation on the STT-RAM sense circuit and proposed a radiation hardened circuit. The sense circuit is implemented in 45 nm CMOS technology. Simulation results show that the proposed circuit is immune to radiation pulses up to 400 Krad