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。     

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.     

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。     

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     

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     

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.     

PSpice Modeling of Opto-electronic devices Using ABM Components

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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     

Modeling of hall devices under locally inverted magnetic field

We present the two-dimensional numerical analysis of carrier transport in semiconductor magnetic sensors exposed to a nonuniform locally inverted induction Bz(x, y). Using a finite element scheme we obtain the electrostatic potential and current density distributions for realistic device and field configurations not accessible to previous modeling methods.     

The underlying factors of the perceived usefulness of using smart wearable devices for disaster applications

Smart wearable devices offer much potential to assist citizens in disasters. To the general public, however, using these devices for disaster applications is still a novel concept. In disasters, most people are reluctant to rely on unfamiliar technologies. Thus, for these devices to become truly useful in disasters, it is important to understand factors that affect their acceptance by the public. Previous studies show that perceived usefulness is a clear antecedent of people’s acceptance of smart wearable devices. However, the underlying factors that affect perceived usefulness itself are not clearly known. Thus, the aim of this study is to fill this gap, and by doing so, to derive some practical implications for solution developers and governments.This study used structural equation modelling to analyse survey data collected from 647 respondents in Japan. We found that the respondents’ perceived usefulness of the current applications of smart wearable devices was a strong predictor of their perceived usefulness of using these devices for disaster applications. Although indirect factors such as the ownership of ICT gadgets and the usage of social media also had some influences, most of their effects were mediated through increasing the respondents’ perceived usefulness of the current applications. In other words, through appreciating the functions of the current applications of smart wearable devices, people can visualise the usefulness of these devices in disaster situations. That being said, we found that in parallel, people also had concerns on the privacy issues of these devices. These findings shed light on the promotion and development of this fast growing technology for disaster applications.     

Modeling and optimization of fringe capacitance of nanoscale DGMOS devices

We analyze the impact of gate electrode thickness and gate underlap on the fringe capacitance of nanoscale double-gate MOS (DGMOS) transistors. We propose an analytical fringe capacitance model considering gate underlap and finite source/drain length. A comparison with the simulation results show that the model can accurately estimate the fringe capacitance of the device. We show that an optimum gate underlap can significantly reduce the fringe capacitance resulting in higher performance and lower power consumption. Also, the effects of process variation in gate underlap devices are discussed. Simulation results on a three-stage ring oscillator show that with optimum gate underlap 32% improvement in delay can be achieved.     

TDD CDMA系统无线资源管理真法的建模与仿真

无线资源管理是第三代移动通信系统中的重要组成部分,用于对业务需求、资源分配、系统容量和稳定性进行控制,而TDD CDMA系统特性及其中引入的智能天线技术使得无线资源管理算法需重新建模设计。本文利用OPNET仿真软件对TDD CDMA系统进行了建模,并且对我们提出的几种适用于TDD CDMA系统的新无线资源管理算法进行了仿真,与传统算法获得的仿真结果对比,验证了其性能增益。