Self-heating in a coupled thermo-electric circuit-device model

The self-heating of a coupled thermo-electric circuit-semiconductor system is modeled and numerically simulated. The system consists of semiconductor devices, an electric network with resistors, capacitors, inductors, and voltage sources, and a thermal network. The flow of the charge carriers is described by the energy-transport equations coupled to a heat equation for the lattice temperature. The electric circuit is modeled by the network equations from modified nodal analysis coupled to a thermal network describing the evolution of the temperatures in the lumped and distributed circuit elements. The three subsystems are coupled through thermo-electric, electric circuit-device, and thermal network-device interface conditions. The resulting system of nonlinear partial differential-algebraic equations is discretized in time by the 2-stage backward difference formula and in space by a mixed finite-element method. Numerical simulations of a one-dimensional ballistic diode and a frequency multiplier circuit containing a pn-junction diode illustrate the heating of the semiconductor device and circuit resistors.     

A transformation method for the solution of power switching circuits based on network topological concepts

In this paper, a general and systematic method for the analysis of varying topology power semiconductor circuits is presented. the changes of the conduction state of the semiconductor switching devices are handled by successive modifications of the tree of the circuit graph. These tree modifications are systematically reflected on a square transformation tensor. On the basis of well known network topological concepts, this generalized transformation tensor can be constructed in a relatively simple way. This tensor constitutes a flexible and powerful tool to assemble automatically the necessary on-switch current and off-switch voltage equations required for any conduction pattern. These manipulations are accomplished with a step-by-step modification procedure of the equations describing the circuit in the most previous conduction state. the basic steps of an algorithm suitable for the practical implementation of the analysis of any power switching network on a digital computer are described, and an example is used to demonstrate the effectiveness of the proposed method.     

碳化硅电力半导体器件在现代电力系统中的应用前景

随着智能电网的建设及可再生能源发电技术的发展,以碳化硅为代表的宽禁带半导体器件以其高功率密度、高电压、高频率、高热导率等优越的物理和电气特性,将在现代电力系统中扮演越来越重要的角色。本文主要介绍了碳化硅功率器件的最新进展,然后对碳化硅功率器件在现代电力系统中的应用前景(可再生能源发电、柔性直流输电、电能路由器、固态断路器)进行了分析和展望。     

Model order reduction of coupled circuit‐device systems

We consider model order reduction of integrated circuits with semiconductor devices. Such circuits are modeled using modified nodal analysis by differential‐algebraic equations coupled with the nonlinear drift‐diffusion equations. A spatial discretization of these equations with a mixed finite element method yields a high dimensional nonlinear system of differential‐algebraic equations. Balancing‐related model reduction is used to reduce the dimension of the decoupled linear network equations, whereas the semidiscretized semiconductor model is reduced using proper orthogonal decomposition. Because the computational complexity of the reduced‐order model through the nonlinearity of the drift‐diffusion equations still depends on the number of variables of the full model, we apply the discrete empirical interpolation method to further reduce the computational complexity. We provide numerical comparisons that demonstrate the performance of the presented model reduction approach. Copyright © 2012 John Wiley & Sons, Ltd.     

半导体设备保护用熔断体的直流短路分断能力

介绍了直流快速熔断体的短路分断试验项目及试验方法,分析了直流快速熔断体的I2t特性、最大电弧能量特性,指出直流快速熔断体可为半导体器件提供有效保护。     

Characterization of charge accumulation and detrapping processesrelated to latent failure in CMOS integrated circuits

A series of measurements were performed on a variety of custom fabricated CMOS test structures to investigate the latent mode of failure due to ESD. Devices were stressed using the current injection test method and measurement of the quiescent current state was used to detect the failure thresholds. The fault sites were further isolated and the failure mechanisms studied by measuring the electrical characteristics before and after exposure to thermal stimulation and light excitation. An analysis of the oxide trapped charge was performed using measured capacitance-voltage profiles. The measurement procedure is useful in the study of electrostatic phenomena in semiconductor devices. The results further support a charge injection/trapping model for latent failures     

Semiconductor device simulation: the hydrodynamic model

VLSI (very large scale integrated) chips incorporate hundreds of millions of semiconductor circuits. To predict the performance of VLSI circuits, the current-voltage (I-V) characteristics of the semiconductor devices are required. Semiconductor device simulation codes provide a way of predicting I-V curves as device parameters are varied, without having to fabricate the device first. Thus, many different designs for devices and circuits can be explored efficiently using computer simulations. Promising designs then can be selected for actual fabrication and testing. A fundamental approach to modeling the quantum transport of electrons and holes in semiconductor devices is the Wigner-Boltzmann equation, the quantum generalization of the Boltzmann equation. Simulating these kinetic equations is computationally expensive. Thus, a hydrodynamic approximation to the kinetic equations, where the density, velocity and temperature of a charge carrier are functions only of three spatial dimensions plus time, offers enormous computational speedups in simulating devices. The article discusses the use of classical and quantum hydrodynamic models in semiconductor device simulation.     

Current-Limiting Fuse Update?New Style Fuse for Protection of Semiconductor Devices

Power equipment utilizing power diodes, silicon-controlled rectifiers (SCR's), and other semiconductor devices continues to take a greater role in electrical distribution systems. Rectifiers, uninterruptible power supply (UPS) systems, ac and dc solid state motor drives, solid state power controllers, and other such equipment require overcurrent protection suited to the special needs of the semiconductor device, and the special requirements for the type of circuitry. The important characteristics of a new line of fuses which is specially designed for the protection of semiconductor devices are described. The major considerations for semiconductor fuse protection are emphasized and a practical protection approach is presented.     

Time domain global modelling of EM propagation in semiconductor using irregular grids

A two‐dimensional finite volume time domain (FVTD) method using a triangular grid is applied to the analysis of electromagnetic wave propagation in a semiconductor. Maxwell's equations form the basis of all electromagnetic phenomena in semiconductors and the drift‐diffusion model is employed to simulate charge transport phenomena in the semiconductor. The FVTD technique is employed to solve Maxwell's equations on an irregular grid and the finite box method is implemented on the same grid to solve the drift‐diffusion model for carrier concentration. The locations of unknowns have been chosen to allow linking coupled Maxwell's equations and transport equations in a seamless way. To achieve suitable accuracy and computational efficiency, using irregular grid topology allows a finer mesh in doped region and at junction, and a coarser mesh in substrate and insulting regions. The proposed scheme has been implemented and verified by characterizing electromagnetic wave propagation at microwave frequency in a semiconductor slab with arbitrary doping profile. Copyright © 2002 John Wiley & Sons, Ltd.     

Efficient and realistic device modeling from atomic detail to the nanoscale

As semiconductor devices scale to new dimensions, the materials and designs become more dependent on atomic details. NEMO5 is a nanoelectronics modeling package designed for comprehending the critical multi-scale, multi-physics phenomena through efficient computational approaches and quantitatively modeling new generations of nanoelectronic devices as well as predicting novel device architectures and phenomena. This article seeks to provide updates on the current status of the tool and new functionality, including advances in quantum transport simulations and with materials such as metals, topological insulators, and piezoelectrics.     

500kV线路关口电能计量装置设计选型的考虑

本文结合笔者现场检测的工作实践经验,针对当前500kV跨区关口电能计量系统存在的一些不合理现象,就500kV线路关口电能计量装置的设计选型(计量装置基本技术要求;关口电能表的配置要求;计量用PT、CT的配置要求及电压、电流二次回路设计要求等)提出一些意见和建议,供同行及有关单位参考。     

交流变频调速传动装置用新型电力半导体器件

电力半导体器件的发展大大促进了交流变频调速传动装置性能的改善，ＭＯＳ栅结构的现代器件的开发成功，可以用很小的输入功率来控制很大的输出功率，并可大大降低装置的功耗，提高工作频率。具有优良反向恢复特性的整流二极管的开发成功，大大降低了高频工作下的功耗。目前的开关器件都是用硅材料制成，但利用ＳｉＣ等材料制成的电力开关器件具有很优良电气特性，是研制理想器件的关键。     

Potential Drops in Metal-Dielectric-Semiconductor Capacitors

During the past few years many of the recent developments in the semiconductor devices field have found their way to the classroom through the collaboration of a handful of well-written books and tutorial papers. However, the electrical engineering student at junior and senior level is usually confused when exposed to subjects where voltage drops in semiconductor structures are involved. Two years ago, the author and collaborators wrote a note concerning potentials in semiconductor structures with added carriers. The approach and language used in that tutorial presentation aroused interest among colleagues in the teaching profession. The same approach and language are used in this paper to discuss potential drops in Metal-Dielectric-Semiconductor capacitors. These devices have excited considerable interest recently and may well be incorporated as subject material in an undergraduate curriculum in electrical engineering.     

Selection of power semiconductor devices for parallel connection

The method of selecting power semiconductor devices for group parallel connection on the basis of models developed on the basis of the measured electrical and thermal parameters and characteristics of certain devices are considered. Experimental data are obtained using the ADIP-6 test equipment. The electrical part of the model is constructed on the basis of the electrical parameters of the volt–ampere characteristic in a high-conductivity condition, and the thermal part is developed on the basis of the electrothermalanalogy method. The parameters of the thermal model are determined on the basis of the measured value of the thermal junction-to-case resistance in the steady-state thermal mode. The electrical and thermal parts of the model are connected through the temperature dependences of the volt–ampere characteristic parameters. A sample of ten power diodes is considered as an example, parallel connections consisting of two diodes are constructed of them, and the electrical and thermal processes are analyzed in this group using the simulation method for all possible combination of the diodes. The potentially reliable and unreliable diode combinations were specified on the basis of the simulation results. The temperature of the semiconductor structure is used as a criterion for determining reliability. A connection in which the temperature of the semiconductor structures of the devices included in the connection did not exceed the admissible limit value was considered as potentially reliable. Two connections, referred to as “potentially reliable” and “potentially unreliable” connections, are considered as an example.     

New Power Semiconductor Devices for Future Generations of Power Supplies

Power Semiconductors are still the driving force for many power electronic systems.In this paper the development of the key power semiconductors devices for power supplies are shown,and their electrical performance discussed.Future directions of the major power semiconductor devices like the IGBT,Super Junction technology and SiC device will be explained.     

Modal synthesis of regulators for an electrical power system on the basis of FACTS devices

A method for the modal synthesis of the control of an electrical power system with FACTS devices is considered. The control is intended for damping the variation of power flow. The method uses the transformation of the equations of the linear model of an electrical power system to a diagonal form. Based on these transformations, a connectivity matrix is constructed and equations for synthesizing the transfer function of the regulator of an electrical power system on the basis of FACTS devices are derived. The regulator ensures the required degree of damping of variations in power flow.     

Fourier approach to semiconductor device modelling

A novel procedure for the numerical modelling of current transport in semiconductor devices is presented. The method is based on high-order trigonometric expansions (Fourier series) of the solution. The expansion coefficients are calculated in a Galerkin-type algorithm. The method offers infinite-order accuracy regardless of the number of spatial dimensions of the model. Well-conditioning and diagonal dominance of the discrete equations render the numerical procedure stable and effective. Significant advantages are expected, particularly for the solution of strongly non-linear multidimensional device models. Properties of the algorithm are demonstrated on standard semiconductor devices.     

An OO-PDE solver for TCAD apps

Technology computer aided design (TCAD) is concerned with modeling the structural and electrical properties of semiconductor devices. The paper discusses the uses of object oriented (OO) methods to design a new base code for all partial differential equation (PDE) based models     

Nonlinear properties of tapered laser cavities

The nonlinear phenomena accompanying the process of light generation in high-power tapered semiconductor lasers are studied using a combination of simulation and experiment. Optical pumping, electrical overpumping, filamentation, and spatial hole burning are shown to be the key nonlinear phenomena influencing the operation of tapered lasers at high output powers. In the particular tapered laser studied, the optical pumping effect is found to have the largest impact on the output beam quality. The simulation model used in this study employs the wide-angle finite-difference beam propagation method for the analysis of the optical propagation within the cavity. Quasi-three-dimensional (3-D) thermal and electrical models are used for the calculation of the 3-D distributions of the temperature, electrons, holes, and electrical potential. The simulation results reproduce key features and the experimental trends.     

A Non-Parabolic Six Moments Model for the Simulation of Sub-100 nm Semiconductor Devices

Macroscopic transport models derived from Boltzmann’s equation by using the method of moments are often used to efficiently evaluate the electrical behavior of semiconductor devices. The most commonly used model is the drift-diffusion model which comprises the first two moments of Boltzmann’s equation. In this model the carrier gas is assumed to be in equilibrium with the lattice, an assumption severely violated in submicron semiconductor devices. Hydrodynamic and energy-transport models have therefore been proposed to overcome this limitation. However, these extended models have never been widely accepted as a viable substitute, because for small devices they often do not deliver the expected improved accuracy. Here we present a non-parabolic six moments model which predicts considerably more accurate currents than the energy-transport model down to gate-lengths as small as 40 nm.