Single Event Effects in NAND Flash memory arrays

We discuss non-volatile memories (NVM) for space applications. The focus will be both on technologies and devices aimed at the mainstream commercial markets and on rad-hard devices. Commercial NVMs are very attractive for space designers due to their large size (tens of Gbits), even though they have several issues related to ionizing radiation. Rad-hard NVMs offer radiation hardness, but are available only in small size (few Mbits). Most of the emphasis in this review paper will be on the current dominant technology in the mainstream market: floating gate flash memories. A comprehensive discussion of total dose and single event effects results for a wide cross section of NVMs will be presented. Finally, we will conclude with a cursory glance at other emerging non-volatile technologies.Index Terms-Ferroelectric devices, flash memory, magnetoresistive devices, nonvolatile memory, phase change memory, radiation effects. I. OVERVIEWN ON-VOLATILE memories (NVMs) are used in a variety of space applications, as data or code memories, and are increasingly needed for future missions. This paper will discuss the technologies and devices available for non-volatile storage in the mainstream and in the rad-hard market, with a strong attention to the radiation sensitivity, which is of primary importance for harsh environments such as space.The work is organized as follows: we will first introduce the basic definitions and metrics concerning NVMs, then explore and compare the major storage concepts. In particular, charge-based, phase-change, ferroelectric, and magnetoresistive memories will be presented, with emphasis on density, performance, reliability, and radiation sensitivity. Architectural information concerning the array organization and peripheral circuitry will be given, highlighting known radiation issues and critical building blocks. A. Key Definitions and MetricsA non-volatile memory is a memory that retains information when powered off. Different terms are used to indicate the act of storing a digital value in a non-volatile memory bit, depending on the memory type and architecture. In charge-based storage, the terms program and erase are used to indicate the injection of Manuscript negative charge into and its removal from (or injection of positive charge into) the charge storage element, respectively. In the context of phase change memories, the terms set and reset are used to indicate the operations leading to the crystallization and amorphization of the phase-change material. For other memories, such as ferroelectric or magnetic, the term write is simply used, as for SRAMs and DRAMs. The association of these operations and terms with the stored digital value ("0" or "1") is arbitrary. In the following we will stick to the conventions most commonly used for each memory type.In addition to familiar parameters such as speed, power consumption, and density, two additional metrics are of main importance for non-volatile memories: retention and endurance. This is because wear-out is usually much stronger in non-volat...

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“…11 for a NOR array (NAND devices show similar effects [63]). A secondary peak appears after exposure to highly-ionizing particles [64].…”

Section: Radiation Effectsmentioning

confidence: 95%

Present and Future Non-Volatile Memories for Space

Gerardin

Paccagnella

2010

IEEE Trans. Nucl. Sci.

139

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“…For these devices the control circuitry, rather than the array itself, has been found to be the most radiation-sensitive part of the device in most studies [17], [20]- [22]. However, charge loss following the impact of a single ion on a FG is all but negligible, and results in a shift of the FG MOSFET threshold voltage , as previously reported [23]- [28]. In particular, the charge loss from the FG following the strike of a single high LET ion is linked to the number of generated carriers, not to those surviving recombination [26], [27].…”

Section: Experimental and Devicesmentioning

confidence: 69%

Angular Dependence of Heavy Ion Effects in Floating Gate Memory Arrays

Cellere

Paccagnella

Visconti

et al. 2007

IEEE Trans. Nucl. Sci.

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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.Index Terms-Floating gate memories, multiple bit upset, single bit upset.

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“…TLC (and MLC to a lesser extent) 3D-NAND devices have low Program-Erase (P/E) limits, on the order of 3000, but this is not an issue for infrequent data transfers like we propose. TLC NAND is especially sensitive to Total Ionizing Dose, radiation-induced soft errors (Single bit upsets, multi-bit upsets, and functional interrupts), as well as some radiation-induced hard errors (stuck bits, dielectric breakdown) [19], [20], [21]. Thank-fully, for the purpose of this study, all of these effects can be mitigated with increased redundancy (i.e., increased weight and power).…”

Section: Onboard Storagementioning

confidence: 99%

Cycler Orbits and Solar System Pony Express

Net

Pellegrini

Parker

et al. 2022

Journal of Spacecraft and Rockets

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In this work, we explore the concept of a secondary "data mule" consisting of a small satellite used to ferry data from a Mars mission to Earth for downlink. The concept exploits the fact that two nearby optical communicators can achieve extremely high data rates, and that a class of trajectories called "cyclers" can carry a satellite between Mars and Earth regularly. By exploiting cycler orbits, the courier needs minimal onboard propulsion.However, cycler orbits have long periodicity, as it can take years for the satellite, Mars, and Earth to repeat their relative geometry. Therefore, we propose the use of a network of such cycler "couriers" on phase-shifted trajectories to achieve a regular cadence of downlink trips. We design a series of search and optimization steps that can output a set of trajectories that at first approximation have low onboard propulsion requirements and can be used for any regular logistics network to and from Mars, then derive the link budget for proximity optical communications to show that this network can ferry large amounts of data.

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Single Event Effects in NAND Flash memory arrays

Cited by 7 publications

References 23 publications

Present and Future Non-Volatile Memories for Space

Present and Future Non-Volatile Memories for Space

Angular Dependence of Heavy Ion Effects in Floating Gate Memory Arrays

Cycler Orbits and Solar System Pony Express

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