The objectives, instrumentation, methods and data leading up to launch of the NASA Living With a Star (LWS) Space Environment Testbed (SET) payload onboard the Air Force Research Laboratory ...Demonstration and Science Experiments (DSX) spacecraft are described. The experiments characterize the space radiation environment and how it affects hardware performance. The payload consists of a compact space weather instrument and a carrier containing four board experiments.
NAND Flash memories are the leader among high capacity non-volatile memory technologies and are becoming attractive also for radiation harsh environments, such as space. For these applications, a ...careful assessment of their sensitivity to radiation is needed. In this contribution, we analyze TID effects on the many different building blocks of NAND Flash memories, including the charge pumps, row-decoder, and floating gate array. Since each of these elements have dedicated circuital and technological characteristics, we identify and study the characteristic failure mode for each part.
We discuss new experimental results on the post-radiation annealing of Floating Gate errors in Flash memories with both NAND and NOR architecture. We investigate the dependence of annealing on the ...program level, linking the reduction in the number of Floating Gate errors to the evolution of the threshold voltage of each single cell. To understand the underlying physics we also discuss how temperature affects the number of Floating Gate errors.
Heavy-ion irradiation of NAND flash memories under operating conditions leads to errors with complex, data-dependent signatures. We present upsets due to hits in the floating gate array and in the ...peripheral circuitry, discussing their peculiarities in terms of pattern dependence and annealing. We also illustrate single event functional interruptions, which lead to errors during erase and program operations. To account for all the phenomena we observe during and after irradiation, we propose an ldquoeffective cross section,rdquo which takes into account the array and peripheral circuitry contributions to the SEU sensitivity, as well as the operating conditions.
Single ions impacting on SiO/sub 2/ layers generate tracks of defects which may result in a Radiation Induced Leakage Current (RILC). This current is usually studied as the cumulative effect of ...ion-induced defects in capacitors with ultra-thin oxides. We are demonstrating and modeling this phenomenon in 10 nm oxides by using Floating Gate memories. The impact of a single, high-LET ion can result in severe retention problems, due to several electrically active defects, which cooperate to slowly discharge the FG. We are also proposing innovative simulation tools to reproduce this phenomenon. Results from simulations fully explain our results, and also agree with existing data on thinner (4 nm) oxides.
In this work we propose a methodology based on a mixed-mode simulation approach to evaluate the impact of finger interruptions in the front-side metallization on the solar cell performance. We apply ...the proposed methodology to typical finger profiles realized with double screen-printing technology. The efficiency degradation induced by finger interruptions is studied as a function of interruption size, interruption position, number of interruptions and finger resistivity.
Single, high energy, high LET, ions impacting on a Floating gate array on grazing or near-grazing angles lead to the creation of long traces of FGs with corrupted information. Up to 30 consecutive ...devices can be involved in the trace left by a single ion. We demonstrate that charge collection at multiple nodes can be expected as the technology advances. One of the major implications is that the widely adopted cosine law should be used with great care when dealing with modern devices, with sizes smaller than 100 nm.
We irradiated floating gate (FG) memories with nor and nand architecture by using different TID sources, including 2 MeV, 98 MeV, and 105 MeV protons, X-rays, and Upsi-rays. Two classes of phenomena ...are responsible for charge loss from programmed FGs: the first is charge generation, recombination, and transport in the dielectrics, while the second is the emission of electrons above the oxide band. Charge loss from programmed FGs irradiated with protons of different energy closely tracks results from Upsi-rays, whereas the use of X-rays results in dose enhancement effects.
Four different technologies of floating gate (FG) memory arrays were subjected to /sup 60/Co gamma-rays and 10 keV X-rays irradiation to evaluate their response to the total ionizing dose. The effect ...of irradiation was a uniform charge loss across the whole array. Irradiation effects can be modeled as the result of two phenomena, namely, the generation of charge in the dielectric layers surrounding the floating gate and its subsequent recombination and drift, and the photoemission of carriers from the charged FG. The second phenomenon is effective at high doses. As a consequence of these two phenomena, devices featuring a smaller FG are less prone to total ionizing dose effects than devices featuring a larger FG, proper of older technological generations. We propose a model that accurately fits experimental data over a broad series of experimental conditions.
We irradiated programmed Floating Gate (FG) memory arrays with different radiation sources, including 10 keV X-rays, /sup 60/Co /spl gamma/-rays, and 27 MeV protons. After irradiation, FGs experience ...a net charge loss which can degrade the stored information in terms of MOSFET threshold voltage. The charge loss is the result of two different phenomena: charge generation/recombination in the oxides and photoemission from the FG. The threshold voltage shift in irradiated devices depends on the radiation source: strong dose enhancement phenomena were found after X-ray irradiation, whereas proton results closely follow /spl gamma/-ray results.
PDF