热预处理对中子辐照直拉硅中热施主的影响

对快中子辐照的直拉硅分别进行了650 ℃和120 ℃快速(RTP)预热处理.450 ℃下不同时间热处理激发热施主,通过四探针测量电阻率和载流子浓度的变化规律,应用傅里叶红外光谱(FTIR)测量间隙氧含量的变化.实验表明经650 ℃预热处理,使辐照样品热施主的形成受到了抑制;Ar气氛RTP预处理条件下,随辐照剂量的增加热施主形成的总量会不断下降.N2气氛RTP预处理,使未辐照样品的热施主形成被抑制,气氛对辐照样品热施主的形成没有明显的影响.     

热预处理对中子辐照直拉硅中热施主的影响

对快中子辐照的直拉硅分别进行了650 ℃和120 ℃快速(RTP)预热处理.450 ℃下不同时间热处理激发热施主,通过四探针测量电阻率和载流子浓度的变化规律,应用傅里叶红外光谱(FTIR)测量间隙氧含量的变化.实验表明经650 ℃预热处理,使辐照样品热施主的形成受到了抑制;Ar气氛RTP预处理条件下,随辐照剂量的增加热施主形成的总量会不断下降.N2气氛RTP预处理,使未辐照样品的热施主形成被抑制,气氛对辐照样品热施主的形成没有明显的影响.     

中子嬗变掺杂直拉硅退火温度与目标电阻率的关系

由于中子辐照诱生的施主(简称中照施主)的产生,使得中子嬗变掺杂直拉硅(NTDCZ Si)的退火行为比较复杂。采用中子嬗变掺杂区熔硅(NTDFZ Si)或者CZ Si热处理消除热施主的退火工艺不能获得真实的目标电阻率。本文研究了NTDCZ Si退火温度与电阻率变化的关系,提出了获得准确目标电阻率的退火温度,讨论了中照施主的产生和消除条件。     

NTDCZSi退火过程中新的施主现象

<正>NTDCZ Si在消除辐照损伤的退火过程中.在750～900℃范围内出现了施主现象.用FTIR,四探针,Hall,正电子湮灭等手段研究了NTDCZ Si的退火行为,并对出现的施主现象进行了讨论.     

CZNTD Si中氧碳对缺陷-杂质复合体行为的影响

本文研究了CZNTD Si中氧碳和缺陷-杂质复合体的热处理行为.分析了辐照和退火中的氧碳沉淀、缺陷-杂质复合体的形成、演变与施主的关系.确定了辐照施主是很少的,而主要是退火中形成的新施主,并且碳对这种施主起着强烈的促进作用.     

NTDCZSi中辐照缺陷的电镜观察

利用硅中固有杂质与缺陷的相互作用来改善硅片质量以适应硅器件日趋严格的技术要求,逐步形成了目前的“缺陷工程”的内容,而将直拉硅(czsi)进行中子嬗变掺杂(NTD)不仅解决了掺杂的均匀性问题,且因大剂量中子辐照在czsi中引入大量的辐照缺陷并与czsi中氧等杂质的相互作用为缺陷工程增添了新的内容,最近的研究表明,中子辐照能强烈地抑制硅片表面缺陷,促进了硅中氧沉淀,并使czsi中氧沉淀定量控制,定域分布,定型转化。从而可改善器件质量,使器件成品率大大提高,因此对NTDCZSi中辐照缺陷的性质,结构及与硅中杂质的相互作用的研究,无疑对解释NTDCZSi中其它实验事实,对改善VLSI器件的材料性能都会具有十分重要的意义。     

中子辐照对硅片表面氧化层错的抑制作用

对硅片表面氧化层错形成机理进行了探讨。并通过中子辐照在直拉硅中引入缺陷，利用辐照缺陷和硅中氧的相互作用，强烈抑制硅片表面氧化层错的产生。     

脉冲中子辐照在硅中引起缺陷的研究

研究了脉冲中子辐照的中子嬗变掺杂 (NTD)硅二极管中缺陷的形成及其退火特征 ,并与热中子辐照样品进行了比较。深能级瞬态谱仪 (DL TS)测量表明硅中主要存在五类电活性缺陷 :氧空位 E1(Ec- 0 .19e V) ,不同荷电态的双空位 E2 (Ec- 0 .2 8e V)和 E4 (Ec- 0 .4 0 e V) ,双空位与氧杂质相结合的络合物 E3 (Ec- 0 .31e V) ,以及与样品材料原生缺陷有关的辐照感生缺陷 E5(Ec- 0 .4 8e V)。实验结果表明 ,脉冲中子辐照由于其高的中子能量和辐照剂量率 ,导致复杂络合物的浓度高于简单缺陷浓度。进一步 4 0 0℃温度以下退火实验显示了缺陷的分解和重建过程     

p型微氮直拉硅中氧施主的电学特性

研究了p型含氮以及不含氮直拉(CZ)硅中热施主(TD)以及氮氧(N-O)复合体的电学性质.硅片在350～850℃范围进行不同时间的退火后,利用四探针和通过室温傅里叶红外光谱(FTIR)分别测量其载流子浓度和间隙氧浓度的变化.实验结果表明:p型含氮直拉硅(NCZ)中热施主的电学特性基本与n型NCZ硅相同,但N-O复合体的消除温度明显低于n型NCZ硅,这是由于p型NCZ硅中硼促进了N-O复合体的消除.     

p型微氮直拉硅中氧施主的电学特性

研究了p型含氮以及不含氮直拉(CZ)硅中热施主(TD)以及氮氧(N-O)复合体的电学性质.硅片在350～850℃范围进行不同时间的退火后,利用四探针和通过室温傅里叶红外光谱(FTIR)分别测量其载流子浓度和间隙氧浓度的变化.实验结果表明:p型含氮直拉硅(NCZ)中热施主的电学特性基本与n型NCZ硅相同,但N-O复合体的消除温度明显低于n型NCZ硅,这是由于p型NCZ硅中硼促进了N-O复合体的消除.     

Low complexity iterative decoding for bit-interleaved coded modulation

Bit-interleaved coded modulation with iterative decoding (ID) is an effective scheme for both AWGN and fading channels because it simultaneously realizes large Euclidean distance and high diversity. In the literature, ID schemes with hard-decision feedback (HDF), as well as soft-decision feedback (SDF), have been investigated. While HDF/ID exhibits a performance inferior to SDF/ID, it is much simpler to implement. To enhance the performance of HDF/ID with moderate additional complexity, we propose a uniform soft-decision feedback ID (USF/ID) scheme. The proposed scheme is applicable in both single antenna and multiple antenna communication systems. The simulation results verify that it achieves impressive performance gain over HDF/ID and has a practically more attractive implementation than SDF/ID, especially for complexity-constrained wireless applications.     

Internet身份证及全球身份管理系统

介绍了一种身份证及相应全球(或全国)身份管理系统,它包括Internet身份证、实名手机、无线(或有线)Internet身份实时识别机、全能手机及全球(或全国)统一身份管理网站等部件.该系统克服了现有身份证不能时刻在线、无法实时确认对方或多方身份、无法实时记录持证人行踪及行为、不能随时随地查阅对方或多方信用、品行、历史的缺点,可以随时随地进行实时身份论证、行踪记录、信用品行查询等身份确认工作.文中介绍了该系统的组成、硬件和软件.     

Synthesis of low band-gap 2D conjugated polymers and their application for organic field effect transistors and solar cells

Two donor-acceptor (D-A) 2-dimensional (2D) conjugated polymers P1 and P2 based on isoindigo (ID) and thienoisoindigo (TID) as acceptor unit and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b´]dithiophene (BDT-T) as donor unit were prepared via Stille coupling and characterized by solution-possessed organic field effect transistors (OFETs) and organic solar cells (OSCs), respectively. By changing the electron-withdrawing component of the conjugated polymer backbone from ID to TID, there have also been diversities in the optical absorption, thermal stability, molecular structure, electrochemical energy level, charge mobility and photovoltaic properties of these two polymers. P1 and P2 exhibited intrinsic p-type semiconductor characteristic with hole mobilities of 3.0 × 10⁻² and 1.2 × 10⁻² cm² V⁻¹ s⁻¹, respectively. When blended with the [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM), the highest power conversion efficiency (PCE) of P1 and P2 were 2.40% and 1.28%, respectively. Our results suggest that ID and TID units are useful building blocks for the further development of efficient organic optical-electrical materials.     

An artificial fingerprint device (AFD): a study of identification number applications utilizing characteristics variation of polycrystalline silicon TFTs

An idea for obtaining unique identification (ID) numbers using polycrystalline silicon (poly-Si) thin-film transistors (TFTs) with a logic LSI compatible process is proposed. Like an actual human fingerprint, the characteristic variations of poly-Si TFTs are utilized for ID numbers in LSIs. The variation of poly-Si TFT characteristics is random, and this method offers unique, nonalterable, and nonduplicable numbers without any special processes, unlike other methods such as flash memory and mask ROM. These characteristics are highly suitable for ID number applications. The device physics of poly-Si TFTs for realizing the stable recognition of ID numbers was studied and a recognition circuit is proposed. The design guidelines for the grain size of poly-Si and AFD applications are also discussed.     

A New Approach to Reducing Output Ripple in Switched-Capacitor-Based Step-Down DC–DC Converters

Rapidly dropping power supply voltages and tight voltage regulation requirements for integrated circuits challenges power supply designers. A novel interleaved discharging (ID) approach is presented to reduce the output ripple in step-down switched-capacitor (SC) dc-dc converters. Simulation and experimental results of a four-stage SC dc-dc converter show that the ID approach can reduce the output ripple by a factor of three. The proposed approach also improves the converter efficiency by 7%. The ID method provides flexibility in the design optimization of step-down SC dc-dc converters     

Privacy‐preserving multireceiver ID‐based encryption with provable security

Multireceiver identity (ID) based encryption and ID‐based broadcast encryption allow a sender to use the public identities of multiple receivers to encrypt messages so that only the selected receivers or a privileged set of users can decrypt the messages. It can be used for many practical applications such as digital content distribution, pay‐per‐view and multicast communication. For protecting the privacy of receivers or providing receiver anonymity, several privacy‐preserving (or anonymous) multireceiver ID‐based encryption and ID‐based broadcast encryption schemes were recently proposed, in which receiver anonymity means that nobody (including any selected receiver), except the sender, knows who the other selected receivers are. However, security incompleteness or flaws were found in these schemes. In this paper, we propose a new privacy‐preserving multireceiver ID‐based encryption scheme with provable security. We formally prove that the proposed scheme is semantically secure for confidentiality and receiver anonymity. Compared with the previously proposed anonymous multireceiver ID‐based encryption and ID‐based broadcast encryption schemes, the proposed scheme has better performance and robust security. Copyright © 2012 John Wiley & Sons, Ltd.     

Transmission Delay Line Based ID Generation Circuit for RFID Applications

A transmission delay line based ID generation circuit is presented for radio frequency identification (RFID) applications. The ID generation circuit has been designed using microstrip transmission lines as delay lines for its operation at ultra high frequency (UHF: 915MHz). The layout has been realized on a flexible substrate using photolithography based fabrication techniques. The circuit has been tested with an on-off-key (OOK) modulated input signal and different combinations of 4bit ID code have been generated. Obtained results confirm the concept and its use in RFID applications     

Modeling and performance analysis of VI‐CRA: A congestion control algorithm for vehicular networks

This study proposes a Vehicle ID‐based CAM Rate Adaptation (VI‐CRA) algorithm for beacon messages in the vehicular network. Foremost, an improved vehicle ID–based analytical model is proposed at the MAC layer of vehicular network. The model weighs the random back‐off number chosen by vehicles participating in the back‐off process, with the vehicle ID incorporated in their respective CAMs. This eventually leads to the selection of a vehicle ID–based random back‐off number, minimizing the probability of collision due to same back‐off number selection. It is worth noting that the improved analytical model outperforms the existing works in terms of average packet delay since only one fourth of the contention window size is used throughout the simulation. To enhance the performance of the analytical model, the paper incorporates a congestion control algorithm, by adapting the rate of CAM broadcast over the control channel. The algorithm is designed considering a wide range of scenarios, ranging from nonsaturated to extremely saturated network (in terms of collision probability) and sparsely distributed to teemed network (in terms of vehicular density). For better analyses of simulation results, the algorithm is applied over different vehicle ID–based back‐off numbers. Simulation results for all the back‐off numbers show that vehicle ID–based CAM rate adaptation algorithm performs better than the traditional fixed CAM rate IEEE 802.11p, even at high vehicular density.     

Efficient Beam‐Training Technique for Millimeter‐Wave Cellular Communications

In this paper, a beam ID preamble (BIDP) technique, where a beam ID is transmitted in the physical layer, is proposed for efficient beam training in millimeter‐wave cellular communication systems. To facilitate beam ID detection in a multicell environment with multiple beams, a BIDP is designed such that a beam ID is mapped onto a Zadoff–Chu sequence in association with its cell ID. By analyzing the correlation property of the BIDP, it is shown that multiple beams can be transmitted simultaneously with the proposed technique with minimal interbeam interference in a multicell environment, where beams have different time delays due to propagation delay or multipath channel delay. Through simulation with a spatial channel model, it is shown that the best beam pairs can be found with a significantly reduced processing time of beam training in the proposed technique.     

Design of a Tapered Transition in a Circular Waveguide (Correspondence)

This correspondence describes a successful design procedure for transitions in circular waveguide. The design procedure is discussed and a universal design curve developed. As an example, one point on a 12-in taper from WRC 283 (2.81-in ID) to WRC 621 (1.28-in ID) is calculated. Test results for the 12-in taper in the 5.925-to 6.425-GHz common carrier band are given.