An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

Memory isolation is a key property of a reliable and secure computing system--an access to one memory address should not have unintended side effects on data stored in other addresses. However, as DRAM process technology scales down to smaller dimensions, it becomes more difficult to prevent DRAM cells from electrically interacting with each other. In this paper, we expose the vulnerability of commodity DRAM chips to disturbance errors. By reading from the same address in DRAM, we show that it is possible to corrupt data in nearby addresses. More specifically, activating the same row in DRAM corrupts data in nearby rows. We demonstrate this phenomenon on Intel and AMD systems using a malicious program that generates many DRAM accesses. We induce errors in most DRAM modules (110 out of 129) from three major DRAM manufacturers. From this we conclude that many deployed systems are likely to be at risk. We identify the root cause of disturbance errors as the repeated toggling of a DRAM row's wordline, which stresses inter-cell coupling effects that accelerate charge leakage from nearby rows. We provide an extensive characterization study of disturbance errors and their behavior using an FPGA-based testing platform. Among our key findings, we show that (i) it takes as few as 139K accesses to induce an error and (ii) up to one in every 1.7K cells is susceptible to errors. After examining various potential ways of addressing the problem, we propose a low-overhead solution to prevent the errors

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Flipping bits in memory without accessing them: an experimental study of DRAM disturbance errors

Is your memory hierarchy stopping your microprocessor from performing at the high level it should be? Memory Systems: Cache, DRAM, Disk shows you how to resolve this problem. The book tells you everything you need to know about the logical design and operation, physical design and operation, performance characteristics and resulting design trade-offs, and the energy consumption of modern memory hierarchies. You learn how to to tackle the challenging optimization problems that result from the side-effects that can appear at any point in the entire hierarchy.As a result you will be able to design and emulate the entire memory hierarchy. . Understand all levels of the system hierarchy -Xcache, DRAM, and disk. . Evaluate the system-level effects of all design choices. . Model performance and energy consumption for each component in the memory hierarchy.

Memory Systems: Cache, DRAM, Disk

The main characteristic of Reconfigurable Computing is the presence of hardware that can be reconfigured to implement specific functionality more suitable for specially tailored hardware than on a simple uniprocessor. Reconfigurable computing systems join microprocessors and programmable hardware in order to take advantage of the combined strengths of hardware and software and have been used in applications ranging from embedded systems to high performance computing. Many of the fundamental theories have been identified and used by the Hardware/Software Co-Design research field. Although the same background ideas are shared in both areas, they have different goals and use different approaches.This book is intended as an introduction to the entire range of issues important to reconfigurable computing, using FPGAs as the context, or "computing vehicles" to implement this powerful technology. It will take a reader with a background in the basics of digital design and software programming and provide them with the knowledge needed to be an effective designer or researcher in this rapidly evolving field.

· Treatment of FPGAs as computing vehicles rather than glue-logic or ASIC substitutes
· Views of FPGA programming beyond Verilog/VHDL
· Broad set of case studies demonstrating how to use FPGAs in novel and efficient ways

Reconfigurable Computing: The Theory and Practice of FPGA-Based Computation

Dynamic random-access memory (DRAM) is the building block of modern main memory systems. DRAM cells must be periodically refreshed to prevent loss of data. These refresh operations waste energy and degrade system performance by interfering with memory accesses. The negative effects of DRAM refresh increase as DRAM device capacity increases. Existing DRAM devices refresh all cells at a rate determined by the leakiest cell in the device. However, most DRAM cells can retain data for significantly longer. Therefore, many of these refreshes are unnecessary. In this paper, we propose RAIDR (Retention-Aware Intelligent DRAM Refresh), a low-cost mechanism that can identify and skip unnecessary refreshes using knowledge of cell retention times. Our key idea is to group DRAM rows into retention time bins and apply a different refresh rate to each bin. As a result, rows containing leaky cells are refreshed as frequently as normal, while most rows are refreshed less frequently. RAIDR uses Bloom filters to efficiently implement retention time bins. RAIDR requires no modification to DRAM and minimal modification to the memory controller. In an 8-core system with 32 GB DRAM, RAIDR achieves a 74.6% refresh reduction, an average DRAM power reduction of 16.1%, and an average system performance improvement of 8.6% over existing systems, at a modest storage overhead of 1.25 KB in the memory controller. RAIDR's benefits are robust to variation in DRAM system configuration, and increase as memory capacity increases.

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RAIDR: Retention-Aware Intelligent DRAM Refresh

The Third Edition of CMOS Circuit Design, Layout, and Simulation continues to cover the practical design of both analog and digital integrated circuits, offering a vital, contemporary view of a wide range of analog/digital circuit blocks including: phase-locked-loops, delta-sigma sensing circuits, voltage/current references, op-amps, the design of data converters, and much more. Regardless of one's integrated circuit (IC) design skill level, this book allows readers to experience both the theory behind, and the hands-on implementation of, complementary metal oxide semiconductor (CMOS) IC design via detailed derivations, discussions, and hundreds of design, layout, and simulation examples.

CMOS Circuit Design, Layout, and Simulation

The power of mixed-signal circuit designs, and perhaps the reason they are replacing analog-only designs in the implementation of analog interfaces, comes from the marriage of analog circuits with digital signal processing This book builds on the fundamental material in the author's previous book, CMOS: Circuit Design, Layout, and Simulation, to provide a solid textbook and reference for mixed-signal circuit design The coverage is both practical and in-depth, integrating experimental, theoretical, and simulation examples to drive home the why and the how of doing mixed-signal circuit design Some of the highlights of this book include: (1) A practical/theoretical approach to mixed-signal circuit design with an emphasis on oversampling techniques; (2) An accessible and useful alternative to hard-to-digest technical papers without losing technical depth; (3) Coverage of delta-sigma data converters, custom analog and digital filter design, design with submicron CMOS processes, and practical at-the-bench deadbug prototyping techniques; (4) Hundreds of worked examples and questions covering all areas of mixed-signal circuit design

CMOS Mixed-Signal Circuit Design

CMOS Circuit Design, Layout, and Simulation, Second Edition

A modern, comprehensive introduction to DRAM for students and practicing chip designers Dynamic Random Access Memory (DRAM) technology has been one of the greatestdriving forces in the advancement of solid-state technology. With its ability to produce high product volumes and low pricing, it forces solid-state memory manufacturers to work aggressively to cut costs while maintaining, if not increasing, their market share. As a result, the state of the art continues to advance owing to the tremendous pressure to get more memory chips from each silicon wafer, primarily through process scaling and clever design. From a team of engineers working in memory circuit design, DRAM Circuit Design gives students and practicing chip designers an easy-to-follow, yet thorough, introductory treatment of the subject. Focusing on the chip designer rather than the end user, this volume offers expanded, up-to-date coverage of DRAM circuit design by presenting both standard and high-speed implementations. Additionally, it explores a range of topics: the DRAM array, peripheral circuitry, global circuitry and considerations, voltage converters, synchronization in DRAMs, data path design, and power delivery. Additionally, this up-to-date and comprehensive book features topics in high-speed design and architecture and the ever-increasing speed requirements of memory circuits. The only book that covers the breadth and scope of the subject under one cover, DRAM Circuit Design is an invaluable introduction for students in courses on memory circuit design or advanced digital courses in VLSI or CMOS circuit design. It also serves as an essential, one-stop resource for academics, researchers, and practicing engineers.

DRAM Circuit Design: Fundamental and High-Speed Topics

A programmable conductor memory cell is read by a sense amplifier but without rewriting the contents of the memory cell. If the programmable contact memory cell has an access transistor, the access transistor is switched off to decouple the cell from the bit line after a predetermined amount of time. The predetermined amount of time is sufficiently long enough to permit the logical state of the cell to be transferred to the bit line and also sufficiently short to isolate the cell from the bit line before the sense amplifier operates. For programmable contact memory cells which do not utilize an access transistor, an isolation transistor may be placed in the bit line located between and serially connection the portion of the bit line from the sense amplifier to the isolation transistor and the portion of the bit line from the isolation transistor to the memory cell. The isolation transistor, normally conducting, is switched off after the predetermined time past the time the bit line begins to discharge through the programmable contact memory cell, thereby isolating the programmable contact memory cell from the sense amplifier before a sensing operation begins.

R. Jacob Baker

Papers

CMOS Circuit Design, Layout, and Simulation

CMOS Mixed-Signal Circuit Design

CMOS Circuit Design, Layout, and Simulation, Second Edition

DRAM Circuit Design: Fundamental and High-Speed Topics

PCRAM rewrite prevention