Investigating Neutron-Induced Single Event Transient Characteristics by TCAD Simulations in 65 nm Technology and Below

Abstract

The neutron-induced secondary ions can cause single event effects through direct ionization, while the LET values of the secondary ions are quite lower than heavy ions in space. Monte Carlo simulation results show that although the maximum LET of secondary ions produced by different energy neutrons incident into the circuit can reach 25.6 MeV-cm2/mg, 98% of the secondary ions have LET values below 16 MeV-cm2/mg. This may lead to different charge collection mechanisms and single event transient (SET) characteristics for neutron. In this paper, the charge collection mechanisms of neutron secondary ions in a single 65 nm planar bulk transistor are studied through 3D TCAD simulations. The neutron-induced SET characteristics in planar bulk transistor, UTBB FDSOI and bulk/SOI FinFET are also compared. Based on the simulation results, UTBB FDSOI shows the best single event effect immunity compared with planar bulk transistor, bulk FinFET and SOI FinFET under the same technology node.