Heavy Ion-, Pulsed Laser-, and Focused X-Ray-Induced Single Event Transients: An Exploration of Charge Collection Mechanisms in an Epitaxial Silicon Diode
Ryder, Kaitlyn Lyle
Spacecraft electronics are subjected to harsh radiation environments, necessitating ground based testing of potential electronics. Single event effects (SEEs), one type of radiation effect, occur when single ionizing particles pass through electronic devices and generate charge in sensitive regions. The generated charge gets collected through drift-diffusion processes and causes a wide range of effects, from current pulses to bit-flips to device failure. Ground-based SEE testing is conventionally performed at high energy particle accelerators, which are capable of emulated the space radiation environment. However, these facilities are experiencing a shortage in available testing hours which has led to the advancement of alternative SEE testing methods. Femtosecond pulsed lasers and picosecond focused X-rays have been identified as viable alternative SEE sources for ground-based testing, but their correlation to the space radiation environment is still under investigation. This dissertation uses a large area, epitaxial silicon diode to explore the charge collection mechanisms resulting from heavy ion-, pulsed laser-, and focused X-ray-induced SEEs. The three SEE sources generate similar amounts of charge in the diode but have drastically different spatial and temporal profiles, resulting in distinct perturbations of the electric field in the diode’s depletion region and device responses. Sentaurus technology computer aided design (TCAD) simulations are used to confirm the variations in electric field modulation and determine which aspects of the charge generation profiles are most critical to the observed differences. These conclusions improve understanding of the fundamental differences between the SEE sources, paving the way for further exploration of the usability of alternative SEE testing sources.