Impact of aging on the SEU immunity of FinFET-based embedded memory systems

Abstract

Due to the rapid technology evolution, embedded computing systems have become a pervasive part of daily life, used for tasks ranging from cost-driven edge computing in the Internet of Things (IoT), up to high-end critical applications (such as aerospace and defense). However, no matter which electronic system the memories are embedded in, they tend to occupy up to 90 % of the total area of the silicon wafer. On the other hand, accelerated aging (bias-temperature instability: BTI) due to technology scaling has become a major factor in degrading memory immunity to transient faults (single-event upsets: SEUs). In this scenario, memory reliability concerns have been brought to the forefront. In the light of the above mentioned, this paper analyses the impact of aging on the SEU immunity of 14 nm FinFET SRAM cell-based embedded memory systems. Experimental results based on HSpice simulations have shown that under certain operating conditions, for 10-year life span, the 6 T SRAM cell SEU immunity can degrade by 58.9 % with respect to the fresh cell (not aged). Moreover, cell aging is strongly dependent on parameters like the temperature in which the cell is operating, as well as the frequency by which the content stored in the cell is inverted during its lifetime. A 256MByte memory system was designed. Simulations indicate that the Mean Time Between Failures (MTBF) of this memory system can degrade up to 23.4 % after a period of 10 years.