Douglas J. Sheldon

Single Event Latchup (SEL) and Total Ionizing Dose (TID) of a 1 Mbit Magnetoresistive Random Access Memory (MRAM)

A 1 Mbit MRAM, a nonvolatile memory that uses magnetic tunnel junction (MJT) storage elements, has been characterized for total ionizing dose (TID) and single event latchup (SEL). Our results indicate that these devices show no single event latchup up to an effective LET of 84 MeV-cm2/mg (where our testing ended) and no bit failures to a TID of 75 krad (Si).

Programmatic Impact of SDRAM SEFI

The Elpida EDS5104(08)ABTA 512Mb SDRAM is examined for programmatic impact of SEE. Use cases for the devices including EDAC and mode register reload are examined. Results indicate some SEE mitigation methods require careful application to achieve system-level benefits, while some event types are essentially mitigated by the application use. In the studied devices, MBE and SEFI are identified and investigated as mechanisms requiring special consideration.

Heavy Ion, Proton and Electron Single-Event Effect Measurements of a Commercial Samsung NAND Flash Memory

Heavy ion, proton and electron single-event effect measurements of 8Gb Samsung single level NAND flash memory are reported. An increase in the heavy ion single bit upset (SBU) cross section was observed on devices that were irradiated with 60Co previously. The proton susceptibility is less than expected. No electron induced upsets were observed.

Electronic failures in spacecraft environments

This paper will provide a review of data describing electronic part failures in spacecraft environments. The details of the spacecraft environment and their individual contributions to the overall failure population will be described. The paper will also present an analysis of new data regarding electronic part failures during spacecraft assembly and test. This data provides an indication of incoming part level quality and insight into handling practices.

Qualification of 128 Gb MLC NAND Flash for SMAP space mission

Screening and qualification of a 128 Gb multi-level-cell (MLC) NAND Flash device for the Soil Moisture Passive Active (SMAP) mission (http://smap.jpl.nasa.gov/) is presented here. The MLC technology used in this high density device requires testing above and beyond the typical space test flow.

Error characterization and mitigation for 16nm MLC NAND flash memory under total ionizing dose effect

This paper studies the system-level reliability of 16nm MLC NAND flash memories under total ionizing dose (TID) effect. Errors that occur in the parts under TID effect are characterized at multiple levels. Results show that faithful data recovery only lasts until 9k rad. Data errors observed in irradiated flash samples are strongly asymmetric. To improve the reliability of the parts, we study error mitigation methods that consider the specific properties of TID errors. First, we implement a novel data representation scheme that stores data using the relative order of cell voltages. The representation is more robust against uniform asymmetric threshold voltage shift of floating gates. Experimental results show that the scheme reduces errors at least by 50% for blocks with less than 3k program/erase cycles and 10k rad. Second, we conduct empirical evaluations of memory scrubbing schemes. Based on the results, we identify a scheme that refreshes cells without doing block erasure. Evaluation results show that parts under this scrubbing scheme survive up to 8k PECs and 57k rad total doses.