An Analysis of the Significance of the ¹⁴N(n, p) ¹⁴C Reaction for Single-Event Upsets Induced by Thermal Neutrons in SRAMs

Abstract

The thermal neutron threat to the reliability of electronic devices caused by 10 B capture is a recognized issue that prompted changes in the manufacturing process of electronic devices with the aim of limiting as much as possible the presence of this isotope nearby device sensitive volumes. 14 N can also capture thermal neutrons and release low-energy protons (through the 14 N(n,p) 14 C reaction) that have high enough linear energy transfer to cause single-event upsets (SEU). Typically, nitrogen is used in thin barrier layers made of TaN or TiN or even as insulator in the form of Si3N4. Numerical simulations on sensitive volumes calibrated on proton and ion experimental data and with an accurate description of the metallization layer on top of the sensitive region show that the presence of nitrogen in these thin barrier layers can be enough to justify the experimentally observed thermal neutron SEU cross section for a static random access memory sensitive to low-energy protons. Nevertheless, the expected SEU cross section from thermal neutrons is usually a few orders of magnitude lower than that of high-energy particles, therefore, not representing an important threat in atmospheric applications. At the same time, for high-energy accelerators, the contribution to the total soft error rate could become substantial, though easy to handle by margins.

Neutron Displacement Damage Cross Section in GaN: Numerical Evaluations and Differences With Si

“…At low energies, one would think that the different threshold energy assumptions would induce differences, but the 14 N(n,p) 14 C reaction predominates the other reactions on the lower energy range. The importance of the large neutron cross section from the N14(n,p) reaction was recently reflected in observed Single Event Effects in SRAMs [45] and is seen again in this analysis. When comparing the cross sections of the two materials, it can be noticed that:…”

Comparative Radiation Response of GaN and Ga2O3 Exposed to Ground-Level Neutrons

“…Note that there is no significant contribution from the equivalent reaction for 16 O; the reaction 16 O(n,γ) 17 O occurs only a few times (see Figure 6a). The release of these products via the capture of neutrons by nitrogen is potentially problematic for the radiation reliability of any material or device containing nitrogen, as recently shown by Coronetti et al [41] in the context of silicon technologies with nitride layers. In the present study, this issue primarily concerns GaN devices.…”