Radiation response of 28 nm CMOS transistors at high proton and neutron fluences for high energy physics applications

The 28 nm CMOS technology was selected as a promising candidate to upgrade electronics of particle detectors at CERN. Despite the robustness of this node to ultra-high levels of total ionizing dose has been proven, the resilience to 10161MeVneq/cm2 fluences is still unknown. Displacement damage effects on two 28 nm CMOS technology processes were therefore investigated through proton and neutron irradiation up to the fluences of interest for high energy physics applications. N-type and p-type core and I/O transistors with different sizes were studied. The results of the extensive irradiation campaign revealed that the 28 nm CMOS node was indeed affected by either proton or neutron. However, through X-ray irradiation it was possible to evidence that the observed radiation-induced degradation was caused by the amount of total ionizing dose deposited during neutron and proton exposure, rather than by displacement damage. These results support that 28 nm CMOS technology is suitable for applications in CERN particle detectors.