Temperature effects on BTI and soft errors in modern logic circuits

摘要

Since thermal responses of the drive current in recent 3D FinFET and conventional planar transistors are different, addressing performance and reliability in advanced VLSI circuits must be reconsidered. This study investigates temperature effects on two of the most problematic reliability issues in modern logic circuits, namely Bias Temperature Instability (BTI) and soft errors. In particular, we initially examine the inversion of temperature effect that strengthens the drive current in 14-nm bulk tri-gate FinFETs with increasing temperature, and model it as a source of threshold voltage reduction. This temperature-induced threshold voltage variation is consequently adapted into our proposed simulation and analysis framework for STI degradation in large combinational circuits. The BTI aging results from our proposed estimation are more pessimistic than that from the conventional approach where the temperature effect is excluded. Simulation results show that long-term BTI aging delay worsens as temperature increases, yet the domination of thermal effect on the drive current leads to overall performance improvement in all circuits under 10-year BTI stress. In addition, soft errors and their masking probabilities in logic circuits are addressed under the inversion of temperature effect and supply voltage variation. The results reveal that soft error immunity in all experimental circuits improves significantly with increasing supply voltage and temperature, mainly due to the increase of critical charge. The average relative soft error rate when the supply voltage changes from 0.4 V to 0.6 V and 0.8 V at 0 degrees C is as low as 3.7% and 0.08% of the average result at 0.4 V, respectively. On average, the relative soft error rate at a particular supply voltage when temperature changes from 0 degrees C to 40 degrees C, 80 degrees C, and 120 degrees C is around 70%, 50%, and 30% of the average result at 0 degrees C, respectively.