The Impact of Ion Strike Time Intervals on Single Event Effect in a 28 nm FPGA

摘要: Advanced nanoscale devices are core components in modern aerospace systems. The on-orbit reliability of the devices faces challenges from Single Event Effects (SEEs) induced by high-energy particles in space. The ground-based irradiation testing is a critical method for predicting on-orbit performance. However, the ground test is an accelerated testing method. The influence of ion strike time intervals (i.e., ion flux) on the SEE sensitivity of advanced nanoscale devices is not yet fully understood. This problem can lead to inaccurate reliability assessment. In this work, the impact of ion strike time intervals on the Single Event Upset (SEU) has been investigated systematically in a 28 nm Static Random Access Memory based (SRAM-based) Field Programmable Gate Array (FPGA). The ground-based irradiation experiments were conducted using various heavy ions under well controlled ion flux levels. The experimental results definitively demonstrate that the device's SEU cross section increases significantly as the ion strike time interval decreases. It shows when the flux exceeds 1000 ions/(cm²·s), the cross section exhibits changes, while it remains unchanged at the flux below 1000 ions/(cm²·s). Moreover, the flux of 1000 ions/(cm²·s) is significantly lower than the typical flux used in SEE testing. This phenomenon was more pronounced at lower core voltages and higher Linear Energy Transfer (LET) values. The analysis reveals that the voltage drop induced by transient pulse from heavy ions is the primary physical mechanism which responsible for the flux dependence. Furthermore, the physical mechanism of the experimental phenomena has been elucidated through Technology Computer-Aided Design (TCAD) and circuit-level simulations. Moreover, the mechanism is equally applicable to other advanced nanoscale devices. This finding provides an essential reference for accurate prediction of on-orbit failure rates of the advanced nanoscale devices.