Microdosimetry approach for determining single-event upsets in microelectronic devices

Abstract

Decreasing the dimension of p-n junctions in microcircuits down to micron sizes and the analogy to the dimensions of biological cells and sub-cell components, provides a motivation for using microdosimetry in microelectronics. Since single-event upsets (SEU) are the most important errors in microelectronic devices, in this work, the microdosimetric one-hit detector model was evaluated to determine the SEU cross-section for microelectronic devices. There were three main assumptions: 1) the device cells are the sensitive volumes. 2) The cells possess the same critical charges and 3) the probability of SEU induction in a cell is a step function. Moreover, the critical charge was considered as the free parameter of the model. Therefore, the number of upsets was obtained equal to the number of effective particle traversals (events) in the device, derived from the single-event microdosimetric distributions. Then, the SEU cross-section was determined. In the calculations there was no need to the electronic response of the device.To examine the model, a 1 k (i.e. 210 bytes memory) 65 nm CMOS bulk SRAM was considered for which the SEU cross-section due to low energy protons obtained by RPP model and experiment had been reported in the literature. Each cell was a rectangle with a dimension of 1.2 μm × 0.6 μm × 1 μm. The single-event distributions for 9 proton energies from 2 MeV to 10 MeV were calculated by Geant4 simulation toolkit. Obtained results showed that for a critical specific energy of 70 Gy (equivalent to a critical charge of 35.56 fC), the SEU cross-sections were found in the best agreement with the reported experimental values within a maximum difference about 40%. Also, the results were comparable with those obtained by the conventional Rectangular Parallelepiped (RPP) model. Eventually, the microdosimetry approach proposed in this work may be considered a potential method to determine the SEU cross-section in any microelectronic device.