Microdosimetry code simulation of charge-deposition spectra, single-event upsets and multiple-bit upsets

An ion microdosimetry extension to the Monte Carlo High Energy Transport Co de (HETC) has been developed to allow tracking of all the reaction products and has been applied to model charge-deposition spectra in pin diodes caus ed by atmospheric neutron spectra, as well as upsets in DRAMs from ground a nd space irradiation by protons. These cases cover sensitive zone sizes ran ging from hundreds of microns to sub-micron. Angular distributions of both incident particles and reaction products are found to be important, particu larly for the prediction of multiple-bit upsets in devices of small feature size.