Neutron Induced Single Event Burnout in Si IGBTs: Experimental Evaluation and Simulation Based Comparison Between Accelerated and Atmospheric Neutron Irradiation Conditions

A B S T R A C T The equivalence between accelerated neutron tests and atmospheric neutron irradiation conditions for evaluating single event burnout (SEB) in insulated gate bipolar transistors (IGBTs) has not been extensively studied, particularly with respect to angular effects. In this work, accelerated neutron irradiation experiments, Geant4 Monte Carlo simulations, and TCAD simulations were combined to investigate the SEB response of high voltage Si IGBTs under different neutron irradiation conditions. The irradiation experiments were used to extract the SEB failure rate under different collector voltages. Geant4 simulations showed that unidirectional accelerated neutron irradiation reproduces the energy characteristics of neutron induced secondary particles in the scoring region reasonably well, but yields a more concentrated downward angular distribution than the simulated atmospheric neutron fields at sea level and 8 km altitude. TCAD simulations further showed that particle incidence angle affects the initial transient response and also influences the establishment and sustainment of Kirk effect enhanced impact ionization and the associated parasitic bipolar conduction. These results indicate that, in a simulation based comparison, the equivalence between accelerated neutron tests and atmospheric neutron irradiation conditions should be assessed from both the incident neutron spectrum and the angular characteristics of secondary particles within the scoring region. Otherwise, the SEB sensitivity inferred from unidirectional accelerated tests may be overestimated