大功率InGaAsP/GaAs量子阱半导体激光器的直流和1/f噪声性质

对大功率InGaAsP/GaAs量子阱(QW)半导体激光器(LD)的直流(DC)特性和小注入下的低频噪声(LFN)特性进行了实验研究.DC检测发现,V-J和I dV/dI-I可以对LD的电流泄漏作出判断.LFN检测发现,小注入下的1/f低频电压噪声幅值Bv(I)∝I<'βv>.理论分析和老化实验均表明,电流指数βv与载流子输运和电流泄漏机制之间有很好的相关性,存在电流泄漏和无辐射复合的器件其|βv|较小,可靠性较差.     

低偏置电流下大功率半导体激光器低频电噪声特性

测量了大功率InGaAsP/GaAs量子阱半导体激光器在五十分之一阈值电流下的电压低频噪声功率谱密度.实验结果显示,激光器的低频电噪声呈现1/f噪声,在不同的偏置电流范围内,1/f噪声幅度随电流的变化关系不同,整体上随偏置电流的增大而减小,实验中并未发现g-r噪声.结合低偏置电流时激光器动态电阻的大小,给出了1/f噪声的模型,分析了在低偏置电流下的1/f噪声主要来自有源区和漏电电阻,其幅度的大小及其随偏置电流的变化趋势与激光器的可靠性有密切的关系.     

电应力对GaAlAs红外发光二极管低频噪声的影响

在宽范围偏置条件下,测量了电应力前后GaAlAs红外发光二极管（IRED）的低频噪声,发现应力前后1／f噪声随偏置电流变化的规律没有改变,但应力后1／f噪声幅值比应力前增加大约i00倍。基于载流子数和迁移率涨落的理论分析表明,GaAlAs IRED的1／f噪声在小电流时反映体陷阱特征,大电流时反映激活区陷阱特征,1／f噪声的增加归因于电应力在器件有源区诱生的界面陷阱和表面陷阱,因而,1／f噪声可以用来探测电应力对该类器件有源区的潜在损伤。     

GaAlAs红外发光二极管功率老化对其1/f噪声特性的影响

在可靠性筛选中检测具有潜在损伤的器件一直是个难题.对GaA lAs红外发光二极管(IRLED)功率老化前后低频噪声的测量发现,1/f噪声幅值与偏置电流的γ次方成正比(小电流区γ=1,在大电流区γ≈2),且老化后1/f噪声幅值比老化前增大2个数量级.基于载流子数涨落和迁移率涨落机制建立了一个GaA lAs IR LED的1/f噪声模型,分析结果表明GaA lAs IR LED的1/f噪声在小电流时反映体陷阱特征,大电流时反映激活区陷阱特征,1/f噪声的增加归因于功率老化诱生的界面陷阱和表面陷阱,1/f噪声可以用来检测GaA lAs IR LED s的潜在缺陷.     

GaAlAs红外发光二极管1/f噪声研究

在宽范围偏置条件下,测量了GaAlAs红外发光二极管（IRLED）的低频噪声,发现1／f噪声幅值与偏置电流If^γ的r次方成正比,在小电流区,r≈1。在大电流区r≈2。建立了一个GaAlAs IRLED的1／f噪声模型,得到与实验一致的定性结果。基于该模型的分析表明．低电流区GaAlAs IRLED的1／f噪声源于体陷阱对非平衡载流子俘获和发射导致的扩散电流涨落,高电流区的1／f噪声源于结空间电荷区附近氧化层陷阱对该处表面势的调制而引起载流子表面复合速率的涨落。该研究结果为1／厂噪声表征GaAlAs IRLED的可靠性提供了实验基础与理论依据。     

基于迁移率波动的MOSFET线性区域1／f噪声模型

统一的1/f噪声模型,例如BSIM3模型,已经在噪声预测与分析中有着广泛的应用,在多数情况下有很好的效果.然而文献[1]中基于物理机理分析的研究表明,统一的1/f噪声模型对处于线性区p-MOSFET不能进行正确的描述:当偏置电压V_gs增加时,该模型低估了噪声功率的增加.据此,本文提出了一种基于物理机理的迁移率波动(MF)1/f噪声模型,并给出了新MF模型与统一的1/f噪声模型在线性区的仿真结果.从仿真结果可以看出,新噪声模型更接近于测试的结果.     

光电耦合器电流传输比的噪声表征

光电耦合器中可俘获载流子的陷阱密度是影响其电流传输比(CTR)的重要因素,并与器件可靠性有密切关系.在器件内部的多种噪声中,1/f噪声可有效地表征器件陷阱密度.本文在研究光电耦合器工作原理以及1/f噪声理论的基础上,建立了光电耦合器的CTR表征模型和1/f噪声模型.在输入电流宽范围变化的条件下,测量了器件的电学噪声和CTR变化,实验结果验证了以上模型的正确性.将CTR模型与噪声模型相结合,得到了CTR与1/f噪声之间的关系.此关系应用于对光电耦合器辐照实验结果的分析,实验结果与理论得到的结论一致.理论与实验结果表明,噪声幅值越大,电流指数越接近于2,则器件的可靠性越差,相同工作条件下CTR的老化衰减量越大,其失效率显著增大.从而证明噪声可表征光电耦合器的CTR并能准确地反映器件的可靠性.     

光电耦合器电流传输比的噪声表征

光电耦合器中可俘获载流子的陷阱密度是影响其电流传输比(CTR)的重要因素,并与器件可靠性有密切关系.在器件内部的多种噪声中,1/f噪声可有效地表征器件陷阱密度.本文在研究光电耦合器工作原理以及1/f噪声理论的基础上,建立了光电耦合器的CTR表征模型和1/f噪声模型.在输入电流宽范围变化的条件下,测量了器件的电学噪声和CTR变化,实验结果验证了以上模型的正确性.将CTR模型与噪声模型相结合,得到了CTR与1/f噪声之间的关系.此关系应用于对光电耦合器辐照实验结果的分析,实验结果与理论得到的结论一致.理论与实验结果表明,噪声幅值越大,电流指数越接近于2,则器件的可靠性越差,相同工作条件下CTR的老化衰减量越大,其失效率显著增大.从而证明噪声可表征光电耦合器的CTR并能准确地反映器件的可靠性.     

MOSFET表面1/f噪声的研究

本文从表面载流子数涨落机构出发,对MOSFET的1/f噪声性质作了较全面的理论和实验研究。将MOSFET的表面1/f噪声理论推广到了所有的偏置区,包括沟道均匀区,线性区和饱和区。对MOSFET的等效输入噪声电压的频率特性、偏置特性和几何特性等进行了实验测试,结果表明与理论规律符合良好。     

低噪声放大器的设计

符号目录: a 有源器件的等效噪声电压/(HZ)~1/2 b 等效输入噪声电流/(HZ)~1/2 a_1 I_c的一个分量 a_2 R_x产生的一个分量 C_u 集电极至基极的等效电容 E_n RMS噪声电压 f 频率 G 电导 I_b 基极电流 I_c 集电极电流 I_(co) 集电极至基极漏电流 I_D 直流电流 I_e 发射微电流     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.