基于IEEE1149.4标准的验证电路设计

介绍了基于IEEE1149.4混合信号测试总线标准的验证电路设计,利用复杂可编程逻辑器件(CPLD)、模拟开关ADG202A和电压比较器LM3¨等器件,实现了该标准所定义的测试结构.它的设计与可观性实验及可控性实验验证了标准的有效性,对于今后推广标准在混合信号芯片中的应用将起到积极的作用.     

Component Value Calculations and Characterizations for Measurements in the IEEE 1149.4 Environment

This paper describes a measurement principle for calculating component values from measurements conducted under less than optimal conditions, as is the case in the IEEE Std 1149.4 environment. Also presented are equations that take into account switch resistances on the signal paths, the output resistance of the signal generator, and the loading effect caused by the input impedance of the voltmeter together with the pin capacitances in parallel to the voltmeter. In addition, the paper presents characterization methods to determine values for these impedances. The inaccuracies achieved in the impedance range from kΩ to MΩ are of the order of few percent.

基于IEEE1149.4的测试方法研究

根据混合信号边界扫描测试的工作机制，提出了符合l149．4标准的测试方法，并用本研究室开发的混合信号边界扫描测试系统进行了测试验证。     

IEEE 1149.4标准实验测试结构设计和扩展研究

本文采用复杂可编程逻辑器件（CPLD）和分立器件,设计实现了IEEE 1149.4混合信号边界扫描标准实验测试结构。为了提高互连测试的故障诊断能力,文中对模拟边界模块（ABM）开关结构进行了一些修改。针对ABM单元的这些修改允许测试者可以将模拟输入信号与多个电压进行比较。当测试者在简单互连或扩展互连中遇到桥接故障,扩展的ABM开关结构使得故障更容易探测。     

A prognostic method for the embedded failure monitoring of solder interconnections with 1149.4 test bus architecture

This paper describes the feasibility of accurate low frequency measurements in predicting the breakdown of modern lead free ball grid array (BGA) interconnections. In these measurements, performed partly with 1149.4 analogue boundary scan, ceramic BGA modules measuring 15×15 mm in width, with 9×9 ball matrixes, were attached on an FR-4 printed wiring board (PWB) and thermally cycled over a temperature range of −40 to +125 °C. The condition of corner interconnections was monitored using the developed measurement methods and construction. In-situ measurements were performed with a datalogger during temperature cycling, accompanied with 1149.4 mixed-signal test bus measurements of corner interconnections performed between cycling intervals. In addition, the measurements were complemented by scanning acoustic microscopy and, X-ray. Monitoring corner interconnections by a simple, low-frequency voltage measurement method with embedded test constructions gives an early warning indication well before the electrical interconnection failures. Of two studied interconnection compositions, the ones with plastic core solder balls (PCSB) proved to be more reliable than the ones with 90/10 PbSn balls.     

SiC稀磁半导体材料研究进展

稀磁半导体(DMS)材料同时利用了电子的电荷和自旋属性,具有优异的磁、磁光、磁电等性能,在材料科学和未来自旋电子器件领域具有广阔的应用前景。系统地概述了SiC基DMS材料的研究进展,介绍了材料的制备方式、结构、性质、铁磁性起源的机理以及器件潜在的应用前景。结合本实验小组的研究工作,重点阐述了材料的结构以及磁性机制。     

窄禁带半导体的光电跃迁效应

光电跃迁效应是窄禁带半导体红外探测器的基本物理过程。本文主要论述窄禁带半导体碲镉汞的带间光吸收跃迁的理论和实验。文中阐述了带间光吸收效应的基本规律的发现及其科学意义,介绍了这些规律在碲镉汞红外探测器材料器件设计中的应用,以及它在解释近年来发现的HgCdTe光电二极管电致负荧光现象方面的应用。     

Printable Semiconductors for Backplane TFTs of Flexible OLED Displays

Studies on printable semiconductors and technologies have increased rapidly over recent decades, pioneering novel applications in many fields, such as energy, sensing, logic circuits, and information displays. The newest display technologies are already turning to metal oxide semiconductors, i.e., indium gallium zinc oxide, for the improvements needed to drive active matrix organic light‐emitting diodes. Convenience and portability will be realized with flexible and wearable displays in the future. This report summarizes recent progress on the development of solution‐processed thin film transistors, especially those deposited at low temperatures for next‐generation flexible smart displays. The first part provides an overview on the history and current status of displays. Then, recent advances in state‐of‐the‐art solution‐processed transistors based on different semiconductors are presented, including metal oxides, organic materials, perovskites, and carbon nanotubes. Finally, conclusions are drawn and the remaining challenges and future perspectives are discussed.     

Coulomb Enhanced Charge Transport in Semicrystalline Polymer Semiconductors

Polymer semiconductors provide unique possibilities and flexibility in tailoring their optoelectronic properties to match specific application demands. The recent development of semicrystalline polymers with strongly improved charge transport properties forces a review of the current understanding of the charge transport mechanisms and how they relate to the polymer's chemical and structural properties. Here, the charge density dependence of field effect mobility in semicrystalline polymer semiconductors is studied. A simultaneous increase in mobility and its charge density dependence, directly correlated to the increase in average crystallite size of the polymer film, is observed. Further evidence from charge accumulation spectroscopy shows that charges accumulate in the crystalline regions of the polymer film and that the increase in crystallite size affects the average electronic orbitals delocalization. These results clearly point to an effect that is not caused by energetic disorder. It is instead shown that the inclusion of short range coulomb repulsion between charge carriers on nanoscale crystalline domains allows describing the observed mobility dependence in agreement with the structural and optical characterization. The conclusions that are extracted extend beyond pure transistor characterization and can provide new insights into charge carrier transport for regimes and timescales that are relevant to other optoelectronic devices.     

The Integration of On-Line Monitoring and Reconfiguration Functions into a Safety Critical Automotive Electronic Control Unit

This paper presents an innovative application of IEEE1149.4 and the Integrated Diagnostic Reconfiguration (IDR) method to an Automotive Electronic Control Unit implemented as a fully-integrated mixed-signal system. The IEEE1149.4 test structure has been embedded and used on-line for interconnect monitoring and signal analysis. This provides higher resolution failure diagnostics enabling localised fault compensation. A novel On-Line Monitoring architecture is presented, that supports real-time testing of the critical circuit nodes. The paper concludes that fault tolerance can be integrated into mixed-signal electronic systems to handle key failure modes.Carl Jeffrey is currently a research associate at Lancaster University. He received an M.Eng. Computer Systems Engineering in 1997 and a Ph.D. in March 2005 in the area of Built-in Test of Integrated Microsystems. Dr. Jeffrey has published 8 key conference and journal papers and is currently contributing to the European Network of Excellence in Design for Micro & Nano manufacture.Rueben Cutajar graduated in Mechanical Engineering from the University of Malta in 1997. Immediately started working for STMicroelectronics (Malta) Ltd, where, as a senior engineer, he was responsible for product and assembly process improvements as well as package failure analysis and reliability. Rueben moved to Lancaster University as a Research Associate in November 2001, where he carried out research and development work related to materials and assembly techniques used for packaging electronics and microsystems in harsh environments, especially automotive applications.Andrew Richardson is currently the Director of the Centre for Microsystems Engineering at Lancaster University. He is also the Scientific Director of Dolphin Integration, Grenoble. His interests are in the integration of Micro & Nano Technology into Heterogeneous systems and Design for Micro & Nano manufacture. Prof. Richardson initiated work on applied research contracts in the early 90’s that addressed test and design for manufacture problems in the field of Microelectronics and Microsystems Technology. To date he has initiated and taken responsibility for deliverables on a range of project, mainly industrial worth over £2.5M to date and published over 100 papers on his work. More recently he has launched a major new European Framework VI Network of Excellence involving 24 partners across Europe and £4.5M of funding to integrate and re-structure the European MNT Design for manufacture community.Steve Prosser graduated in 1979 from Oxford University with a degree in Chemistry and continued there to complete his doctorate in Physical Sciences in 1982. His industrial career started with THORN EMI Central Research Laboratories developing novel silicon-based chemical sensors. In 1985 he joined Lucas Industries (now TRW) and has led the development of advanced sensors for automotive and aerospace applications. Expatriate assignment with Lucas took him overseas for three years working as Engineering Manager for Lucas Control Systems (Schaevitz Sensors) in Virginia, USA. In 1998, he returned to the UK to become Chief Engineer—Technology within TRW Automotive Electronics. He is responsible for the technology development for advanced electronics and sensors. He is currently Chairman of the Institute of Physics Instrumentation Science and Technology Group and also Visiting Professor of Engineering at Lancaster University.Steve Riches joined Micro Circuit Engineering (MCE) in May 1999, after 16 years at The Welding Institute, where he worked on assembly and packaging techniques for microelectronics and laser processing. Since that time, he has worked as Business Development Manager for MCE, where he has been involved in establishing capabilities for the manufacture of ruggedised displays and packaging of microsystems.     

The Photo-Hall Effect in High-Mobility Organic Semiconductors

High-mobility crystalline organic semiconductors are important for applications in advanced organic electronics and photonics. Photogeneration and transport of mobile photocarriers in these materials, although very important, remain underexplored. The photo-Hall effect can be used to address the fundamental charge transport properties of these functional molecular materials, without the need for fabricating complex transistor devices or chemical doping. Here, a photo-Hall effect is demonstrated in organic semiconductors, using a benchmark molecular system rubrene as an experimental platform. It is shown that this technique can be used to directly measure the charge carrier mobility and photocarrier density, decouple the surface and bulk transport phenomena, and thus significantly deepen the understanding of the mechanism of photoconductivity in these high-performance molecular materials.     

Ion-Gating Engineering of Organic Semiconductors toward Multifunctional Devices

Ion-gating engineering provides a new way to bridge electronics and ionics, and more importantly, bringing unprecedented opportunities for organic semiconductors (OSCs) based bioelectronics and solid-sate physics. Compared with conventional-dielectric gating, ion gating shows unique features in an extremely large electric field, high transconductance, low operating frequency, and ultrahigh carrier concentration. It therefore boosts the rapid development of different organic devices, including neuromorphic devices and amplifying transducers, and offers a powerful strategy to probe the charge transport, thermoelectric and even superconducting properties of organic materials at different scales. In this review, first, the fundamental mechanism of ion gating is discussed to enable multifunctional devices. The electrolyte materials and organic semiconductors are also summarized that are widely used in ion-gated devices and their associated properties are examined. Moreover, key concepts of manipulating ion–electron coupling are highlighted for opening up new frontiers in organic multifunctional electronics. Finally, the challenges and perspectives on the ion gating of OSCs are proposed to highlight the directions that deserve attention in this emerging interdisciplinary field.     

An Improved Pseudo-Random Generator Based on the Discrete Logarithm Problem

Under the assumption that solving the discrete logarithm problem modulo an n-bit safe prime p is hard even when the exponent is a small c-bit number, we construct a new pseudo-random bit generator. This new generator outputs n – c – 1 bits per exponentiation with a c-bit exponent and is among the fastest generators based on hard number-theoretic problems.     

半导体材料中自旋极化的光学注入与探测

综述了自旋电子学的一些新进展,重点介绍了自旋极化的光学注入、弛豫机制和光学探测等方面的内容,并涉及到与自旋有关的自旋霍尔效应(SHE)和纯自旋流等物理效应.     

半导体/SiO2纳米复合材料的溶胶-凝胶制备

总结了溶胶-凝胶法制备半导体/SiO2纳米复合材料的研究进展。目前,通过该方法已制备了镶嵌在SiO2玻璃中的II-VI族I、II-V族I、-VII族和IV族等半导体;形态上,除玻璃块体和薄膜外,还出现了核壳结构的纳米颗粒和同轴纳米电缆。     

锰掺杂ZnO稀磁半导体的制备及铁磁性能

用溶胶-凝胶法,在超声波辅助条件下制备了Mn掺杂ZnO(Zn1-xMnxO,x≤0.05)稀磁半导体(DMS)纳米晶粉末样品.用透射电子显微镜(TEM)、X射线衍射(XRD)仪、超导量子干涉(SQUID)测磁仪分别对样品形貌、结构和磁性能进行了表征.较低的掺杂浓度下样品很好地保持ZnO的纤锌矿结构,随着掺杂浓度x的增加,样品的晶格常数近似线性增大,没有观察到杂质相.样品Zn0.98Mn0.02O显示了很好的铁磁性,居里温度在350 K以上.     

Modulated Thermoelectric Properties of Organic Semiconductors Using Field‐Effect Transistors

Organic thermoelectric materials, which can transform heat flow into electricity, have great potential for flexible, ultra‐low‐cost and large‐area thermoelectric applications. Despite rapid developments of organic thermoelectric materials, exploration and investigation of promising organic thermoelectric semiconductors still remain as a challenge. Here, the thermoelectric properties of several p‐ and n‐type organic semiconductors are investigated and studied, in particular, how the electric field modulations of the Seebeck coefficient in organic field‐effect transistors (OFETs) compare with the Seebeck coefficient in chemically doped films. The extracted relationship between the Seebeck coefficient (S) and electrical conductivity (σ) from the field‐effect transistor (FET) geometry is in good agreement with that of chemically doped films, enabling the investigation of the trade‐off relationship among σ, S, carrier concentration, and charging level. The results make OFETs an effective candidate for the thermoelectric studies of organic semiconductors.     

Unravelling the Molecular Origin of Organic Semiconductors with High-Performance Thermoelectric Response

A decisive prerequisite toward systematic development of high-efficiency organic thermoelectric materials is not only thoroughly understanding the microscopic physical processes controlling the performance, but also precisely correlating such processes and the macroscopic properties to the basic chemical structures. Here, by using multiscale first-principles calculations, the interplay among thermoelectric properties, microscopic transport parameters, and molecular structures for the whole family of small-molecule organic thermoelectric materials is rationalized, and general molecular design principles are concurrently formulated. It is unveiled that thermoelectric power factor of a wide variety of molecular semiconductors is directly proportional to a unified quality factor, and high-performance thermoelectric response demands to boost the intermolecular electronic coupling, and to suppress the interaction of electron with lattice vibrations. Furthermore, it is uncovered that extending the π-conjugated backbones along the long axis, and maximizing the networks of intermolecular S···S or C H···π contacts meet the proposed material design rule.     

Partial Scan Testing on the Register-Transfer Level

This paper presents a methodology to insert scan paths in a design that is specified on the Register Transfer Level (RT-Level). The results indicate that selecting registers on this level guarantees a reduction in DFT design time and improvement of fault coverage, without incurring high hardware overhead.     

Ohmic Contact in 2D Semiconductors via the Formation of a Benzyl Viologen Interlayer

The fabrication of a polymeric Ohmic contact interlayer between a metal and a 2D material using solution‐processed benzyl viologen (BV) is reported here. Predoping of the polymer alters the contact surface to obtain electron‐doped materials with ultrahigh work functions that significantly enhance the current density across the contact and reduce the contact resistance and Schottky barrier height. The fabrication of solution‐processed polymeric contacts for the preparation of high mobility MoS₂, WSe₂, MoTe₂, and BP (black phosphorous) FETs with significantly lowered contact resistance is demonstrated. Ohmic contacts are achieved and produce 3‐, 700‐, 3000‐, and 17‐fold increases in electron mobilities, respectively, when the bottom gate voltage is 10 V compared to those respective materials alone. Ambipolar and p‐type 2D material based FETs could, therefore, be transformed into n‐type FETs. Most importantly, the devices exhibit excellent stability in both ambient and vacuum.