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Abstract-Quantum-dot cellular automata (QCA) has been widely advocated as a new device architecture for nanotechnology. Using QCA, the innovative design of digital systems can be achieved by exploiting the so-called capability of processing-in-wire, i.e., signal manipulation proceeds at the same time as propagation. QCA systems require low power together with the potential for high density and regularity. These features make QCA an attractive technology for manufacturing memories in which the in-wire paradigm can be exploited for storage purposes. This paper proposes a novel parallel memory architecture for QCA implementation. This architecture is based on storing information on a QCA line by changing the direction of signal flow among three clocking zones. Timing of these zones requires two additional clocks to implement a four-step process for reading/writing data to the memory. Its operation has been verified by simulation. It is shown that the requirements for clocking, number of zones, as well as the underlying CMOS circuitry are significantly reduced compared with previous QCA parallel architectures.Index Terms-Emerging technologies, memory architecture, quantum-dot cellular automata (QCA), quantum computing.

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The design of circuits and systems in Quantum-dot Cellular Automata (QCA) is still in infancy. The basic logic primitive in QCA is the majority voter (MV), that is not a universal function; so, inverters (INV) are also required. Blocks (referred to as tiles) are utilized in this article. A tile with a combined logic function of MV and INV (MV-like function) is proposed. It is shown that the MV-like tile can be effectively used in logic design as basic primitive. Tiles based on both the fully populated (FP) and non-fully populated (NFP) grids are investigated in detail. Various arrangements in inputs and outputs are also possible among the 4 sides of a grid, thus defining different tiles. Using a coherence vector simulation engine, it is shown that the 3 × 3 grid offers versatile logic operation. Different combinational functions such as majority-like and wire crossing are obtained using these tiles. Tile-based design of different circuits is compared to gate-based and SQUARES designs.

Abstract-Quantum-dot Cellular Automata (QCA) has been widely advocated as a new device architecture for nanotechnology. QCA systems require extremely low power, together with the potential for high density and regularity. These features make QCA an attractive technology for manufacturing memories in which the paradigm of memory-in-motion can be fully exploited. This paper proposes a novel serial memory architecture for QCA implementation. This architecture is based on utilizing new building blocks (referred to as tiles) in the storage and input/output circuitry of the memory. The QCA paradigm of memory-in-motion is accomplished using a novel arrangement in the storage loop and timing/clocking; a three-zone memory tile is proposed by which information is moved across a concatenation of tiles by utilizing a two-level clocking mechanism. Clocking zones are shared between memory cells and the length of the QCA line of a clocking zone is independent of the word size. QCA circuits for address decoding and input/output for simplification of the Read/Write operations are discussed in detail. An extensive comparison of the proposed architecture and previous QCA serial memories is pursued in terms of latency, timing, clocking requirements, and hardware complexity.

International audienceThis article presented a survey of dependability issues faced by multi-core architectures at nanoscale technology nodes. Existing solutions against these challenges were also discussed, describing their scope of application, from technology level methodologies, to design approaches to the metrics required to evaluate the overall dependability of a system. In the future, the constant reduction of the feature size of the devices will exacerbate the issues related to aging and soft errors. This will create further challenges and at design level, an integrated design approach that will cope with the occurrence of faults at any time of their occurrence i.e., at manufacturing (thus increasing yield) and in the field (thus increasing reliability) will become more and more important to obtain economically viable and dependable systems. Dependability assessment will also need an integrated approach for cross-layer, pre- and post-silicon techniques for “just right”dependability assessment in order to avoid “overdesign”for dependability using classic guard-banding methodologies

Abstract-Error correction codes (ECCs) have been used for decades to protect memories from soft errors. Single error correction (SEC) codes that can correct 1-bit error per word are a common option for memory protection. In some cases, SEC codes are extended to also provide double error detection and are known as SEC-DED codes. As technology scales, soft errors on registers also became a concern and, therefore, SEC codes are used to protect registers. The use of an ECC impacts the circuit design in terms of both delay and area. Traditional SEC or SEC-DED codes developed for memories have focused on minimizing the number of redundant bits added by the code. This is important in a memory as those bits are added to each word in the memory. However, for registers used in circuits, minimizing the delay or area introduced by the ECC can be more important. In this paper, a method to construct low delay SEC or SEC-DED codes that correct errors only on the data bits is proposed. The method is evaluated for several data block sizes, showing that the new codes offer significant delay reductions when compared with traditional SEC or SEC-DED codes. The results for the area of the encoder and decoder also show substantial savings compared to existing codes.Index Terms-Double error detection, error correction codes (ECCs), single error correction (SEC), soft errors.

This paper presents a detailed analysis of the yield of embedded static random access memories (eSRAM) which are generated using a compiler. Defect and fault analysis inclusive of industrial data are presented for these chips by taking int o accotmt the design constructs (referred to as kernels) and the physical properties of the layout. The new tool CAYA (Compiler-based Array Yield Analysis) is based on a characterization of the design process which accounts for fault types and the relation between functional and structural faults; a novel empirical model is proposed to facilitate the yield calculation. Industrial data is provided for the analysis of various configurations with different structures and redundancy. The effectiveness and accuracy as provided by CA YA are assessed with respect to industrial designs.