SiC光控异质结达林顿晶体管的导通机理

利用窄能隙SiCGe三元合金，采用SiCGe/SiC pn异质结产生基极光电流方法，提出了新型SiC光控达林顿异质结晶体管功率开关结构，并用二维数值模拟软件对其导通机理进行了研究. 分析结果表明，SiC光控异质结达林顿晶体管在近红外区内具有明显光控开关特性，其饱和导通压降为4.5V左右，且宜于强光工作.     

SiCGe/3C-SiC异质结光控达林顿晶体管的设计与仿真

针对抗电磁干扰的需要提出了一种由SiCGe/3C-SiC异质结构成的光控达林顿晶体管设计.用多维器件模拟软件ISE对这种新型功率开关进行了特性仿真.结果表明,与采用其他结晶类型的碳化硅衬底相比,SiCGe与3C-SiC间较小的晶格失配有利于提高器件性能,可使其最大共射极电流增益达到890,获得最好的光触发特性和较好的Ⅰ-Ⅴ特性,饱和压降大约为4V.     

Design and Simulation of a Light-Activated Darlington Transistor Based on a SiCGe/3C-SiC Hetero-Structure

针对抗电磁干扰的需要提出了一种由SiCGe/3C-SiC异质结构成的光控达林顿晶体管设计.用多维器件模拟软件ISE对这种新型功率开关进行了特性仿真.结果表明,与采用其他结晶类型的碳化硅衬底相比,SiCGe与3C-SiC间较小的晶格失配有利于提高器件性能,可使其最大共射极电流增益达到890,获得最好的光触发特性和较好的Ⅰ-Ⅴ特性,饱和压降大约为4V.     

Bufferless broadcasting: a low power distributed circuit techniquefor broadcasting 10-Gb/s chip input signals

Bufferless distributed circuit (BDC) broadcasting is proposed as a technique for broadcasting high-speed chip input signals to a series of on-chip destination cells as needed in crosspoint switch, parallel multiplier, distributed amplifier, etc., chip designs. In contrast with conventional techniques that use an on-chip buffer to assist broadcasting, BDC broadcasting offers the advantage of lower signal delay and power dissipation. In an experimental GaAs heterojunction bipolar transistor (HBT) 8×4 crosspoint switch assembly, BDC broadcasting was found to achieve a 40% power savings with little or no penalty in jitter or bit error rate performance at a 10-Gb/s data rate     

A comparison study of CMOS T/R switches using gate/source-terminated field-plate transistors

In this paper, high-linearity CMOS single-pole-double-throw (SPDT) RF switches using the proposed field-plate (FP) transistors were fabricated and compared. The 0.13-μm CMOS processed FP metal was connected to the gate terminal and source terminal individually. The discussion throughout dc characteristic, linearity, and power property was given. The gate-terminated FP (FP-G) NMOS provided a lower gate resistance being confirmed for low-noise and high-efficiency design while the source-terminated FP (FP-S) NMOS with relatively lower leakage current, higher linearity, and higher breakdown under high V_ds is confirmed to be suitable for high-linearity power design. Several switches using standard transistor, FP-S, and FP-G NMOS transistors were implemented and analyzed. Comparison on the switch characteristics and application has been done. The novel designs indicated that the proposed FP-based switches provided good potentials in power handling and harmonics rejection without sacrifice of power consumption, chip area, and insertion loss.     

一种能改善GaAsHBT自热效应的复合管

根据负反馈原理,提出一种复合管结构来补偿异质结双极型晶体管（HBT）的自热效应。仿真和测试曲线结果表明,在较宽环境温度和较大输出电流密度范围内,复合管的自热效应得到了有效抑制,静态工作点稳定,采用此复合管设计的功率放大器的1dB提高了2dB,线性得到了改善。     

n-Al0.15Ga0.85 N/p-6H–SiC heterostructure and based bipolar transistor

Heterojunction bipolar transistor (HBTs) based on Al0.15Ga0.85 N/6H–SiC heterojunction was fabricated. Room-temperature current–voltage (I–V) characteristics of n-Al0.15Ga0.85 N/p-6H–SiC emitter–base heterojunction exhibited good rectifying behavior with a forward current 5 × 10⁻² A and reverse current 3 × 10⁻⁹ A at 10 V and −10 V, respectively. Analysis of the temperature dependent I–V characteristics of this heterojunction revealed a barrier height of 1.1 eV. The fabricated n-Al0.15Ga0.85 N/p-SiC/n-SiC bipolar transistor did not exhibit common-emitter operation, however, common-base operation was observed with current gain β = IC/IB ranging in 75–100.     

基于Matlab/Simulink的SiC MOSFET建模与分析

针对现阶段SiC MOSFET建模研究无法应用在电机控制系统领域的现状,提出了一种基于Matlab/Simulink的SiC MOSFET仿真电路模型。对功率器件的动态特性和静态特性进行综合分析,采用非分段受控电流源模型模拟功率器件静态特性,具体分析SiC MOSFET的开关过程,同时采用曲线拟合的方法对影响器件开关过程的非线性电容进行表征,在Matlab/Simulink中建立SiC MOSFET等效电路模型。为了验证模型准确性,将仿真结果与数据手册中的数据进行比较分析,仿真结果表明所建模型可以较为准确地描述SiC MOSFET动、静态特性,开通时间和关断时间误差均小于7%,对比结果验证了模型的准确性和有效性。建立的模型为SiC MOSFET在电机控制策略仿真及应用领域提供了参考依据。     

Low power optical gate HBT driver array for 2.5 Gbit/s ATMswitching

A four element driver array for optical gates in a 2.5 Gbit/s optical ATM switch is presented. The circuit uses a GaAs-GaAlAs heterojunction bipolar transistor (HBT) technology. It enables a switching time of <300 ps and current up to 150 mA with <400 mW per gate power consumption     

β-SiC/Si heterojunction bipolar transistors with high currentgain

The combination of single-crystalline β-SiC and Si permits the fabrication of a heterojunction bipolar transistor (HBT) in which the conventional poly-Si or single-crystalline Si emitter is replaced with a single-crystalline SiC emitter, a technique compatible with existing Si technology. A common-emitter current gain of 800 is attained with this device. The value of the ideality factor n of the base current is 1.1, which suggests that diffusion current is dominant. The large number of misfit dislocations at the SiC/Si heterojunction are ineffective as recombination centers and do not deteriorate the characteristics of the HBT     

High frequency small signal characteristics of the SCL heterojunction transistor

The space-charge-limited (SCL) heterojunction transistor is represented as a planar unit area structure. The internal small signal admittances of the device are derived as functions of transit angle or frequency and the base width and built-in-field. A practical GaAs-Ge heterojunction transistor is used to illustrate the derived admittance characteristics. It is shown, for the model chosen, that the internal transconductance is controlled predominantly by the collector region.The SCL heterojunction transistor is subsequently represented by an equivalent circuit constructed of the internal admittances. The two port Y parameters of the device are then derived from the equivalent circuit and shown as functions of transit angle or frequency. The unilateral gain is also derived as a function of transit angle or frequency.Finally the f_τ and f_max of the GaAsGe model are calculated and it is shown that the maximum value of f_max of 50 GHz obtainable is limited by collector transit time effects.     

PCS/W-CDMA dual-band MMIC power amplifier with a newly proposed linearizing bias circuit

A personal communications service/wide-band code division multiple access (PCS/W-CDMA) dual-band monolithic microwave integrated circuit (MMIC) power amplifier with a single-chip MMIC and a single-path output matching network is demonstrated by adopting a newly proposed on-chip linearizer. The linearizer is composed of the base-emitter diode of an active bias transistor and a capacitor to provide an RF short at the base node of the active bias transistor. The linearizer enhances the linearity of the power amplifier effectively for both PCS and W-CDMA bands with no additional DC power consumption, and has negligible insertion power loss with almost no increase in die area. It improves the input 1-dB gain compression point by 18.5 (20) dB and phase distortion by 6.1/spl deg/ (12.42/spl deg/) at an output power of 28 (28) dBm for the PCS (W-CDMA) band while keeping the base bias voltage of the power amplifier as designed. A PCS and W-CDMA dual-band InGaP heterojunction bipolar transistor MMIC power amplifier with single input and output and no switch for band selection is embodied by implementing the linearizer and by designing the amplifier to have broad-band characteristics. The dual-band power amplifier exhibits an output power of 30 (28.5) dBm, power-added efficiency of 39.5 % (36 %), and adjacent channel power ratio of -46 (-50) dBc at the output power of 28 (28) dBm under 3.4-V operation voltage for PCS (W-CDMA) applications.     

Structural and photoelectrical characteristics of Si/6H-SiC heterojunctions prepared by hot-wall chemical vapor deposition

Based on a potential application for the Si/SiC heterojunction to realize light control of SiC devices, structures and electrical properties of boron-doped silicon layer deposited on the n-type 6H-SiC substrate by hot-wall chemical vapor deposition were investigated in this paper.X-ray diffraction analysis and scanning electronic microscopy were used to characterize the crystal structure and morphology of the deposited silicon layer. Results of I–V and C–V measurements indicated that the heterojunction was abrupt manifesting obvious p–n junction properties. During the I–V measurement, the Si/SiC heterojunction developed a remarkable photovoltaic effect under illumination condition.     

GaAs—Si photon-activated switch

A light-activated low-level switch (LAS) has been developed for multiplexing applications. The switch consists of an electroluminescent GaAs p-n diode and a double-emitter silicon transistor. (Both NPN and PNP units have been made.) The two, light emitter and detector, are coupled optically. The switch is a substantial improvement over existing switching devices used in multiplexers. A general design theory based on the Ebers & Moll [1] low-level transistor model is given, with special emphasis on breakdown voltage, ON impedance, offset voltage, and switching speed. It is shown how the design considerations lead to a specific geometry for the detector. Results of extensive testing are reported.     

Analytical investigation of dead space effect under near-breakdown conditions in GaInP/GaAs composite double heterojunction bipolar transistors

The dead space effect under near-breakdown conditions in GaInP/GaAs composite collector double heterojunction bipolar transistor (DHBT) is investigated analytically. Using the dead space corrected model, the breakdown voltage is found to decrease with GaAs spacer thickness as reported from experiments. The common-mode emitter IV characteristics for the DHBT are simulated until the onset of multiplication with good agreement with reported experimental results [IEEE Elec. Dev. Lett. 15 (1994) 10]. A proposed optimised structure is simulated with comparably good turn-on I–V characteristics and improved breakdown performance.     

An Ebers-Moll model for the heterostructure bipolar transistor

An Ebers-Moll model for the heterostructure bipolar transistor (HBT) is developed. The model describes both single and double heterojunction transistors with or without band spikes and applies to uniform or graded base HBTs. Model parameters are directly related to device parameters such as doping densities, dimensions and band spikes. Junction velocities are introduced to describe the transport of carriers across the junctions. Results demonstrate that even for compositionally graded junctions, transport across the junctions may limit HBT performance if the base is graded. Use of the model is illustrated by examining a recently proposed technique for extracting conduction band spikes by comparing forward and inverted I-V characteristics.     

DC parameter extraction of equivalent circuit model in InGaAsSb heterojunction bipolar transistors including non-ideal effects in the base region

This paper presents the DC parameter extraction of the equivalent circuit model in an InP-InGaAsSb double heterojunction bipolar transistor (HBT). The non-ideal collector current is modeled by a non-ideal doping distribution in the base region. Then several consequent non-ideal effects, which have always been neglected in typical HBTs, are studied using Medici device simulator. Moreover, the associated DC parameters of VBIC model are extracted accordingly. The equivalent circuit model is in good agreement with the measured data in I_C-V_CE characteristics.     

碳化硅器件挑战现有封装技术

碳化硅(SiC)器件的新特性和移动应用的功率密度要求给功率器件的封装技术提出了新的挑战。现有功率器件的封装技术主要是在硅基的绝缘栅双极晶体管(Insulated Gate Bipolar Transistor,IGBT)和金属氧化物半导体场效应晶体管(Metal Oxide Semiconductor Field Effect Transistor,MOSFET)等基础上发展起来的,并一直都在演进,但这些渐进改良尚不足以充分发挥SiC器件的性能,因而封装技术需要革命性的进步。在简述现有封装技术及其演进的基础上,主要从功率模块的角度讨论了封装技术的发展方向。同时讨论了功率模块的新型叠层结构以及封装技术的离散化、高温化趋势,并对SiC器件封装技术的发展方向做出了综合评估。     

A 3.2-V operation single-chip dual-band AlGaAs/GaAs HBT MMIC poweramplifier with active feedback circuit technique

This paper describes the design and experimental results for a 3.2-V operation single-chip AlGaAs/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (IMMIC) power amplifier for GSM900 and DCS1800 dual-band applications. The following two new circuit techniques are proposed for implementing the power amplifier. One is an on-chip HBT bias switch which in turn switches the amplifier between 900 and 1800 MHz. The proposed switch configuration allows the switch using a high turn-on voltage of 1.3 V of AlGaAs/GaAs HBT's to operate with a 3-V low supply voltage, because the switch circuitry needs no stacked configuration. The other is an active feedback circuit (AFB) to prevent permanent failure of HBT's in the output power stage even under severe conditions of oversupply voltage and strongly mismatching load. Experimental results revealed that the proposed feedback circuit, which works as a voltage limiter, can protect the output stage HBT's from an excessive collector voltage swing even when the amplifier is operated under a condition of a 5-V oversupply voltage and a 10:1 voltage standing-wave ratio (VSWR) mismatching load. Under a normal condition of 3.2 V and a 50-Ω matching load, the IC is capable of delivering an output power of 34.5 dBm and a power-added efficiency (PaE) of 52% in a GSM900 mode, and a 32-dBm output power and a 32% PAE in a DCS1800 mode     

High frequency performance of SiC heterojunction bipolartransistors

A compact heterojunction bipolar transistor (HBT) model was employed to simulate the high frequency and high power performances of SiC-based bipolar transistors. Potential 6H-SiC/3C-SiC heterojunction bipolar transistors (6H/3C-HBT's) at case temperatures of 27°C (300 K) through 600°C (873 K) were investigated. The high frequency and high power performance was compared to AlGaAs/GaAs HBT's. As expected, the ohmic contact resistance limits the high frequency performance of the SiC HBT. At the present time, it is only possible to reliably produce 1×10^-4 Ω-cm² contact resistances on SiC, so an f_T of 4.4 GHz and an f_max of 3.2 GHz are the highest realistic values. However, assuming an incredibly low 1×10^-6 Ω-cm² contact resistance for the emitter, base, and collector terminals, an f_T of 31.1 GHz and an f_max of 12.7 GHz can be obtained for a 6H/3C-SiC HBT