Research on single-event function interruption mechanism of MRAM chips

The single-event functional interruption (SEFI) has grown in importance in advanced process node integrated circuits, and the single-event effect has become one of the key causes of spacecraft failure as process sizes have shrunk. As a new type of memory device with high-speed reading and writing, the magnetic random access memory (MRAM) has excellent radiation resistance of the memory cell, but its peripheral circuits are more sensitive to single-event effects. Pulsed laser analysis of the functional effect of SEFI on chips is an efficient method. The pulsed laser focusing micro-beam is used to locate the control module whose sensitive area is located in the peripheral reading circuit of MRAM, and the equivalent LET threshold of SEFI under the reading 0 cycle is 25 $(\mathrm{M}\mathrm{e}\mathrm{V}\cdot {\text{cm}}^2)/\text{mg}$, and the data presents a million-level flip error when SEFI occurs, and the number of flip bits continues to rise with the continuation of irradiation, and the current continues to rise by more than 3 mA. The analysis shows that there is a positive feedback effect of the current on the control port when the flip occurs, and the simulation model of the MRAM reading circuit is established through the resistor-equivalent memory unit, and the loop feedback conclusion between the control module, the sensitive amplification, and the memory unit is obtained. Simultaneously, single-event faults are injected into the MRAM sensitive area control module using circuit-level simulation software. It is discovered that the more sense amplifier (SA) units that are simultaneously controlled by the control module, the faster the SA’s output error time. It is also discovered that the more SA that are simultaneously controlled, the more vulnerable they are to irradiation and function interruption. Based on the above research, it is proposed to suppress the “loop feedback” from the MRAM peripheral circuit structure or use asynchronous processing between the control module and the SA for the anti-radiation reinforcement design.