Neutron-induced single event upset simulation in Geant4 for three-dimensional die-stacked SRAM*

Abstract

Three-dimensional integrated circuits (3D ICs) have entered into the mainstream due to their high performance, high integration, and low power consumption. When used in atmospheric environments, 3D ICs are irradiated inevitably by neutrons. In this paper, a 3D die-stacked SRAM device is constructed based on a real planar SRAM device. Then, the single event upsets (SEUs) caused by neutrons with different energies are studied by the Monte Carlo method. The SEU cross-sections for each die and for the whole three-layer die-stacked SRAM device is obtained for neutrons with energy ranging from 1 MeV to 1000 MeV. The results indicate that the variation trend of the SEU cross-section for every single die and for the entire die-stacked device is consistent, but the specific values are different. The SEU cross-section is shown to be dependent on the threshold of linear energy transfer (LETth) and thickness of the sensitive volume (Tsv). The secondary particle distribution and energy deposition are analyzed, and the internal mechanism that is responsible for this difference is illustrated. Besides, the ratio and patterns of multiple bit upset (MBU) caused by neutrons with different energies are also presented. This work is helpful for the aerospace IC designers to understand the SEU mechanism of 3D ICs caused by neutrons irradiation.

Proton- and Neutron-Induced SEU Cross-Section Modeling and Simulation: A Unified Analytical Approach

“…Figure 4 shows rough approximations for the effective LET of secondary particle as functions of neutron energies. Following (10) and (12), one can obtain an approximate expression for estimating the energy dependence of the neutron-induced cross-sections:…”

“…The neutron-induced nuclear reaction crosssections at relatively high energies ( n ε ≥ 10 MeV) are approximately constant, max n Σ ~ 1-2 bn, whereas the low-energy ( n ε ≤ 2 MeV) cross-sections are usually much smaller, although the behavior of the curve can be very complex [28]. Following (10) and (12), one can obtain an approximate expression for estimating the energy dependence of the neutron-induced cross-sections:…”

“…Another challenge is the neutron-induced soft error rate (SER), arising from the finite value of the neutron flux in the atmosphere or even at the sea level (~13 cm −2 h −1 ) [6][7][8][9]. The physical processes involved in the failure mechanisms from neutrons and low-energy protons are quite complex and strictly speaking require cumbersome computational approaches based on numerical simulations (e.g., GEANT4, TCAD or MRED) [10][11][12]. Such systems are often inaccessible, inconvenient to use and require highly skilled users.…”