Reliability of smart power devices

Smart power devices of the last generation are able to integrate a full electronic system, including logic and analog functions and power drivers, in a true single chip solution exploiting the advanced features made available by mixed BCD processes developed for this purpose. The complexity of the ICs and their applications together with the severe stress conditions which these devices can experience in the field makes the reliability assurance of the Smart Power ICs a very challenging task and for this purpose a complete approach is necessary combining an application oriented IC qualification methodology with structural evaluations to test the intrinsic reliability of the basic process elements. In this context the knowledge of the main failure mechanisms is fundamental both for an effective detection in qualification and for an early prevention during IC design.     

智能微尘的研发与应用前景

智能微尘是一种能够以无线传输方式传递信息的微型电子机械传感器(MEMS),它可以感应到周围诸多环境参数的微观改变,从光线强度变化到振动能量大小,几乎无所不能。它能够收集到大量有效数据,并能进行适当的计算与处理,然后利用双向无线通信装置将这些信息在相距1000英尺的微尘器件间往来传送。虽然智能微尘技术的应用前景十分美好,但当前仍存在着许多技术难题使它暂时还不能获得广泛应用。研究者和商业开发者们在对其潜在的应用价值热切观望之际,也谨慎地指出了设计问题和供电问题需要尽快解决。     

怎样获得出色的集成功率器件

“智能功率”和“集成功率器件”等词汇已经被用滥了,而且其定义也非常含糊。本文中所指的“智能功率”或“集成功率器件”是已封装的器件,能完成信号处理和功率处理功能。     

Modeling of discrete semiconductor devices

Numerical modeling established itself as a powerful tool for the analysis and design of discrete semiconductor devices and integrated circuits. The paper reviews the basic semiconductor equations, the physical internal mechanisms implemented in the present simulation programs and the numerical methods used to solve the nonlinear semiconductor equations. Selected results of numerical simulation of high frequency and high power discrete devices are given. The exemples comprise bipolar and FET devices made on Si or GaAs, operating in steady state or transient conditions and modeled in one or two dimensions.     

基于智能移动设备的A超眼球生物测量系统

眼球生物测量具有重要的临床意义,为了提高眼球生物测量设备的便携性与经济性,文中提出一种基于智能移动设备的A超眼球生物测量系统。该系统由数据采集模块和智能移动设备构成,两者通过蓝牙接口进行信息交互,数据采集模块用于发射超声和接收回波,智能移动设备用于显示和处理回波数据、整机控制及远程通信。体模实验和在体实验均表明,文中系统测量结果准确可靠,稳定性好。如果医师利用自带的智能移动设备,可以大大降低眼球生物测量的成本值得在临床推广。     

智能家居设备远程绑定过程的安全评估与增强

为了对智能家电进行远程管理,移动端应用程序得到了广泛应用,智能家电设备、用户和云端之间的远程绑定成为实现设备安全远程访问的关键。为此,主要研究了智能家居远程绑定中的安全威胁问题。首先,建立了远程绑定的全过程状态机模型;然后,基于该模型,系统分析了针对10款远程家居设备的远程绑定方案,并发现了多个安全缺陷;最后,提出了一个增强的远程绑定方案IoTBinder,该方案针对现有远程绑定中静态设备 ID容易被暴力破解或泄露问题,从云端生成动态设备ID并通过用户传递给设备完成远程绑定。通过安全协议分析工具ProVerif的验证表明,IoTBinder可有效保护远程绑定过程,性能开销可以忽略不计。     

使用基于模型的设计测试程序开发智能设备

越来越多的智能设备正在进入我们生活的角角落落，包括您的电脑、智能电话、最新的苹果iPad等。而设备中的嵌入式软件还在不停地促使您的汽车、洗衣机和电网向着智能化的方向发展。事实上，在我们的生活中，已经越来越难找到不包含嵌入式软件的大型电子设备了。     

User acceptance of smart wearable devices: An expectation-confirmation model approach

Smart wearable devices have become one of the most popular interactive items in the “smart” era that prioritizes “mobility.” There is significant scholarly interest in not only promoting the successful diffusion of this technology but also providing improved user experience to users of these devices. In line with this trend, this study explores users’ perceptions of smart wearable devices and introduces a comprehensive research model that employs factors that are primarily extracted using the expectation-confirmation, technology acceptance, and flow models. The results derived using both confirmatory factor analysis and structural equation modeling methods (N = 1,380) indicate that users’ intentions to use smart wearable devices are determined by five influential factors: satisfaction, enjoyment, usefulness, flow state, and cost. Both users’ confirmation and service and system quality play notable determinative roles in the research model. Implications and suggestions are presented considering the results.     

Modeling and control for smart Mesoflap aeroelastic control

This paper introduces a novel concept termed Smart Mesoflaps for Aeroelastic Recirculation Transpiration (SMART) to render mass and momentum transfer for controlling shock/boundary-layer interactions in supersonic jet inlets. The SMART concept consists of a matrix of small flaps designed to undergo local aeroelastic deflection to achieve proper mass bleed or injection when subjected to shock loads. To optimize the performance of this system, NiTi shape memory alloy is used as an actuator for the flaps to control the amount of recirculation. The focus of this paper will be the subsystem modeling and control of a single flap. After a relatively detailed model is developed, a simpler model is generated, and it is experimentally shown that this approximation is adequate for control purposes. Next, the control strategy for this subsystem, subject to hysteresis and actuator saturation, is presented. A basic proportional integral derivative (PID) controller is enhanced using a hysteresis compensator (HC) and an error governor (EG). A generalized error governing scheme for PID controllers to compensate for actuator saturations is also developed. This EG method is generalizable to any stable process controlled by a PID. Finally, the PID with HC and the error governing method is experimentally applied to a benchtop SMART subsystem.     

Modeling of electron-hole scattering in semiconductor devices

It is generally assumed in device modeling that the effects of electron-hole scattering can be fully accounted for by a suitable reduction in the electron and hole mobilities with injection level, without modifying the semiconductor device equations themselves. Physical considerations indicate that this is not the case, and that electron-hole collisions introduce a direct coupling between the electron and hole currents. This is determined from first principles, and the results of a Boltzmann calculation are described. The key result is that the impact of an electron-hole scattering event depends on the relative drift velocity between electrons and holes. In low injection, the effective minority-carrier diffusion mobility cannot be assumed to be identical to majority-carrier mobilities or to minority-carrier drift mobilities. In high injection, a reduction in the conductivity mobility does not imply a reduction in the ambipolar diffusion constant. Results for p-i-n diodes are given     

基于N-Gram算法的智能家居设备固件安全检测方案

本文提出基于N-Gram的智能家居设备固件安全检测方案,该方案主要采用N-Gram算法提取设备固件中可以代表智能家居设备固件的特征子序列,将单个设备固件特征向量化,在向量空间里将安全的设备固件与存在漏洞的设备固件进行特征比对,从而实现了利用智能家居市场上已知漏洞去检测其他智能家居设备的相似漏洞的功能,同时提高了安全工程师对设备固件的漏洞发现效率。     

An agent-based self-adaptation architecture for implementing smart devices in Smart Space

Smart Space is a major currently challenging domain that includes ubiquitous, grid, and pervasive computing to provide intelligence, insight, and vision for emerging world of intelligent environment, products, services and human interaction. Smart Space consists of various objects (devices and applications) and, their extremely tight integration of and coordination between information world and physical resources. In Smart Space, people are allowed to acquire useful information and control devices anytime and anywhere with various smart devices. However the physical world where devices are deployed has much uncertainty and uncontrollable conditions, so that it is impossible to make devices suited to all situations. To achieve user satisfaction and overcome the system failure, devices in Smart Space must be dependable, secure, safe, and efficient, and operate in real-time. In addition, they must be scalable, cost-effective and adaptive. Especially, to deal with uncertainty and uncontrollable condition, devices in Smart Space could be more intelligent in the adaptation. In this paper, we propose an agent-based self-adaptation architecture for implementing smart devices in Smart Space. A self-adaptive smart device reasons about its state and environment, and adapts itself at runtime automatically and dynamically in response to changes. Also we present an adaptation mechanism used to implementing a self-adaptive system.     

Short distance data transmission method using inaudible high-frequencies between smart devices

Telecommunication Systems - Because wireless communications with inaudible high-frequency signals are used in limited areas due to their low speed, this paper proposes a data communications method...     

Modeling total dose effects in narrow-channel devices

Exposure of MOSFET's to large doses of ionizing radiation causes bulk oxide charging and an increase in interface state density. The former shifts device operation thresholds. The latter degrades channel mobility gmand increases subthreshold leakage. The degree of damage introduced depends on oxide electric fields. Making gate dimensions smaller complicates modeling a number of ways. Some of these complications are addressed in this paper. Specifically, problems associated with narrowing the width of the device channel are investigated. It is shown that differential charging of the field and gate regions leads to an effective widening of the channel. For typical n-channel MOSFET's used in very-large-scale integrated circuits, this widening may amount to 0.3 µm after a 10-krad:SiO2dose of ionizing radiation. A model incorporating channel widening and radiation-induced mobility degradation is proposed.     

Modeling of GaN optoelectronic devices and strain-inducedpiezoelectric effects

Modeling of nitride-based LEDs and laser diodes requires a fast modular tool for numerical simulation and analysis. It is required that the modeling tool reflects the primary physical processes of current injection, quantum well (QW) bound-state dynamics, QW capture, radiative, and nonradiative transitions. The model must also have the flexibility to incorporate secondary physical effects, such as induced piezoelectric strain fields due to lattice mismatch and spontaneous polarization fields. A 1-D model with a phenomenological well-capture process, similar to that developed by Tessler and Eisenstein, has been implemented. The radiative processes are calculated from first principles, and the material band structures are computed using k·p theory. The model also features the incorporation of such effects as thermionic emission at heterojunctions. Shockley-Read-Hall recombination, piezoelectric strain fields, and self-consistent calculation of the QW bound states with dynamic device operation. The set of equations underlying the model is presented, with particular emphasis on the approximations used to achieve the previously stated goals. A sample structure is analyzed, and representative physical parameters are plotted. The model is then used to analyze the effects of incorporation of the strain-induced piezoelectric fields generated by lattice mismatch and the spontaneous polarization fields. It is shown that these built-in fields can accurately account for the blue-shift phenomena observed in a number of different GaN LEDs     

4H-SiC基超结器件各向异性的TCAD建模分析

基于文献报道的4H-SiC材料的各向异性物理特性,首次提出4H-SiC基超结器件的各向异性物理模型,并对不同晶向的碰撞电离分别进行考虑。基于该模型,我们对 和 两种晶向晶圆的4H-SiC超结器件的电学特性进行了研究。与 晶圆相比, 晶圆的碰撞电离系数较小,可以实现更高的击穿电压。由于碰撞电离各向异性,与传统4H-SiC基器件相比,超结器件的二维电场分布可以将 晶圆器件的击穿电压从 晶圆器件的60%提高到72%。     

Intelligent file transfer for smart handheld devices based on mobile cloud computing

Most methods of file transfer between mobile devices have to take considerable time to obtain and input target identifiers. To speed up file sharing of mobile devices, an intelligent file transfer framework is designed based on mobile cloud computing. Only single‐finger action is performed in the proposed framework, which just drags the file to the target face on the touchscreen of a mobile device. The dragged file can be transmitted to the target receiver who can either get the file immediately as her/his mobile device is online or receive the file later after connecting to the Internet. Our framework provides the following features: (i) users do not need to know the target identifier in advance; (ii) users do not need to input identity information by themselves; and (iii) users can select a specific target among multiple candidates from the camera of a mobile device. The intelligent file transfer framework reveals an efficient architecture and innovative user interfaces to transfer files between mobile devices, which can significantly reduce the complexity and difficulty of file sharing. An Android‐based prototype is implemented to verify the feasibility and superiority of our framework. Experimental results show that our approach outperforms existing schemes and can save large amounts of time in file sharing for mobile users. Copyright © 2015 John Wiley & Sons, Ltd.     

Random telegraph noise and leakage current in smart power technology DMOS devices

Random telegraph signal (RTS) noise, analyzed in time and frequency domains, and leakage current are studied in smart power technology double-diffused metal oxide semiconductor (DMOS) field effect transistors. The RTS noise is strongly correlated with the presence of an excess leakage current in the device. The observed drain current (gate bias) dependencies of relative (absolute) RTS amplitude and gate voltage dependence of RTS mean pulse widths suggest that the RTS noise sources are located under the gate and in the drain-body region. A model, where the multicell DMOS structure is considered as parallel connection of submicron MOSFETs, is proposed to account for the results.     

Design and implementation of a wireless sensor network architecture using smart mobile devices

Wireless sensor networks improve the quality of human daily life like ubiquitous city and healthcare services as well as the fundamental monitoring such as environment pollution, tunnel monitoring, earthquake diagnostic, and so on. To increase usability and feasibility of collected sensor data, a wireless sensor network should be required to apply a variety of mobile devices to give the information at anytime and anywhere to users. Thus, we present multi-sensor centric smart sensor network architecture using general mobile devices in order to provide more efficient and valuable sensor network application and services. The proposed system architecture is based on IEEE 802.15.4-2006 standard with smart mobile devices. We also show some scenarios with on-demand request and real time event driven data to show the feasibility of the proposed architecture using five kinds of sensors such as magnetic, photodiode, microphone, motion and vibration. Based on the experiment results, we show that the proposed system has the potential as smart mobile device-based wireless sensor network architecture.     

Modeling of planar varactor frequency multiplier devices withblocking barriers

Models for optimization of planar frequency triplers with symmetrical C-V curves are presented. The roles and and limitations of various blocking barriers (oxide, Mott, heterojunction) are discussed. Devices with undoped drift regions (BIN) gave moderate efficiency but a broad range of power generation, whereas the devices with doped drift regions (BNN) have high efficiency in a narrower power window. In particular, an upper power limit of the BNN is caused by electron velocity saturation. Implementations in SiO₂ -Si and AlAs-GaAs and means for increasing the power of BNN structures are considered