Cross-Section Estimation for Assessment of Circuit Susceptibility to Radiation

The aggressive scaling of nanometric VLSI technologies increases the integrated circuits susceptibility to radiation, especially to single-event effects. Ordinarily, circuit vulnerability is evaluated through the cross-section metric, which represents the number of errors observed in a given time window, divided by the particle fluence (integral of flux) passing through the circuit in the same time frame. Obtaining the cross-section requires performing an expensive radiation test. Therefore, any way of predicting it, even with a loss in accuracy, is important to allow early design choices to reduce the expected error rate of an electronic circuit intended to be deployed in radiation environments. In this context, this work proposes a methodology framework to evaluate cross-sections of combinational standard cells against radiation-induced errors. The procedure extracts the most sensitive cell areas according to input vectors, indicating the radiation-sensitive charge collection areas. This study suggests different approaches to evaluate the cross-section through physical design characteristics. First, it explores the scenario for low LET particles, identifying the charge collection areas. Subsequently, it considers the heavy ions particle range to estimate the maximum cross-section. Results indicate that cross-section is almost 9.5 times lower for low-energy particles. Literature results suggest that charge collection could arise outside the sensitive plane. This finding could lead to further investigation, and the method proposed can serve as an effective alternative for estimating circuit cross-section.