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 Code (HETC) has been developed to allow tracking of all the reaction products and has been applied to model charge-deposition spectra in pin diodes caused by atmospheric neutron spectra, as well as upsets in DRAMs from ground and space irradiation by protons. These cases cover sensitive zone sizes ranging from hundreds of microns to sub-micron. Angular distributions of both incident particles and reaction products are found to be important, particularly for the prediction of multiple-bit upsets in devices of small feature size.