Synergistic effects of total ionizing dose and displacement damage on bipolar and BiCMOS circuits in high energy physics applications

At CERN, the functionality of the accelerator complex depends significantly on the reliability of electronic control devices. The environment inside the structures hosting particle accelerators is particularly hostile to electronic components due to the presence of ionizing and non-ionizing radiation, as well as high-energy particles, which degrade the performance of devices. Ionizing radiation induces charge trapping in gate oxide and dielectric materials with possible formation of interface traps at the oxide/semiconductor interface. Non-ionizing radiation, such as neutrons, displaces semiconductor atoms within the crystal lattice, thus generating punctual or cluster of defects. Additionally, high-energy particles induce the formation of charge in sensitive regions of devices, which can lead to single-event effects. In these challenging environments, the high demand for components and the prohibitive cost of rad-hard solutions have led to the widespread use of Commercial Off-The-Shelf (COTS) systems. However, these systems must be qualified to ensure their tolerance to radiation. In certain applications, bipolar devices are preferred over CMOS devices due to their resilience to latchup, a destructive event that compromises the functionality of CMOS systems. Nonetheless, bipolar devices suffer from displacement damage, which is typically negligible in MOSFETs. Consequently, the combination of ionizing and non-ionizing radiation can produce synergistic effects in bipolar devices, where the overall damage cannot be predicted by simply summing the individual contributions of each radiation type. These effects complicate the qualification of highly distributed systems within the Large Hadron Collider (LHC), as radiation levels vary significantly in terms of the ratio between displacement damage and total ionizing dose. Within this context, the thesis aims to investigate the synergistic effects of ionizing and non-ionizing radiation on various types of bipolar and BiCMOS integrated circuits. It also explores the impact of these effects on the radiation qualification of components for highly distributed systems in the LHC.