Ion Impact Detection and Micromapping With a SDRAM for IEEM Diagnostics and Applications

Abstract

Ion Electron Emission Microscopy (IEEM) can provide an alternative approach to microbeams for micrometric characterization of the sensitivity map to Single Event Effects (SEE) of an electronic device. In IEEM technique, a broad (not focused) ion beam is sent onto the Device Under Test (DUT). Secondary electrons emitted by the target surface during each ion impact are collected and focused by a system of electrostatic lenses and finally imaged by a high-rate and high-resolution position detector. We will report on the IEEM working at the SIRAD irradiation facility located at the 15 MV Tandem of INFN Legnaro National Laboratories. To estimate the IEEM resolution, a SDRAM is a good candidate to be used as a reference target, thanks to the micrometric feature size of the array of memory cells and the precise knowledge of their physical locations. Since an electronic device is not a good secondary electrons emitter, to ensure a copious and uniform emission of secondary electrons from the DUT, a very thin (100 nm) self-standing Silicon Nitride (Si 3 N 4 ) membrane with a Au deposition (40 nm) is mounted on the top of the SDRAM. The Au/Si 3 N 4 membrane and the underlying SDRAM are irradiated with a heavy ion beam. The physical map of ion impacts detected by the SDRAM is then compared with the one reconstructed by the IEEM in the same 500 ms time interval. Index Terms-Ion electron emission microscopy, radiation effects, SDRAM, single event upset (SEU).

A new irradiation facility for neutron-induced Single Event Effect studies at LNL

“…The SIRAD capability in the field of SEE studies is improved by an Ion Electron Emission Microscope (IEEM) system [15], installed at the end of the beam line, that can reconstruct the positions of individual ion impacts with a resolution of few micrometers. Any SEE signals induced by ions in the DUT may be used to temporally tag the IEEM reconstructed events.…”