NUMERICAL-SIMULATION OF HEAVY-ION CHARGE GENERATION AND COLLECTION DYNAMICS

This paper describes a complete simulation approach to investigating t he physics of heavy-ion charge generation and collection during a sing le event transient in a PN diode. The simulations explore the effects of different ion track models, applied biases, background dopings, and LET on the transient responses of a PN diode. The simulation results show that ion track structure and charge collection via diffusion-domi nated processes play important roles in determining device transient r esponses. The simulations show no evidence of rapid charge collection in excess of that deposited in the device depletion region in typical funneling time frames (i.e., by time to peak current or-in less than 5 00 ps). Further the simulations clearly show that the device transient responses are not simple functions of the ion's incident LET. The sim ulation results imply that future studies and experiments should consi der the effects of ion track structure in addition to LET and extend t ransient charge collection times to insure that reported charge collec tion efficiencies include diffusion-dominated collection processes.