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。     

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。     

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.     

CMOS反相器低频噪声模型及可靠性表征研究

为了表征CMOS反相器的可靠性,从其负载电流和输出电压的特性入手,详细推导了一种基于载流子波动理论的低频噪声模型,并由实验数据验证了模型的准确性.由实验结果可知,负载电流功率谱密度随频率的增加而减小,遵循1/f噪声的变化规律;得到了负载电流归一化噪声功率谱密度与器件尺寸的关系.通过深入研究1/f 噪声与界面态陷阱密度的关系,验证了1/f噪声可用于表征CMOS反相器的可靠性,证明了噪声幅值越大,器件可靠性越差,失效率显著增大,为评价CMOS反相器的靠性提供了一种可行及有效的方法.     

光电耦合器总剂量辐照的噪声表征

 本文在研究光电耦合器工作原理、辐照理论及1/f噪声理论的基础上,分析了光电耦合器辐照噪声产生机理及特性,建立了光电耦合器总剂量辐照损伤噪声模型.研究结果表明,随着辐照总剂量增强, LED及光敏管氧化层中引入的氧化层陷阱密度增多,载流子数涨落增强,从而使电压噪声功率谱密度增加.实验结果验证理论分析的正确性,电压噪声功率谱密度可作为光电耦合器辐照损伤表征参量.     

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.     

I/f噪声源及MOS器件中的1/f噪声

1／f噪声,由于其反映了器件的质量、可靠性等参数,其研究越来越为人们所重视。本文首先较为系统地介绍了1／f噪声源两种较为成熟的理论：载流子数涨落和迁移率涨落模型,最后将研究MOS晶体管中1／f噪声的现象。在n管中,较为成功地用△N模型;而在PMOS晶体管中,△μ模型可较为成功地解释其1／f噪声特性。     

光电耦合器件低频噪声特性与可靠性老化研究

在宽的输入偏置电流范围条件下,开展了光电耦合器件低频噪声特性测试与功率老化和高温老化的可靠性试验研究。结果表明,光电耦合器件的低频噪声主要是内部光敏晶体管1/f噪声,并随输入偏置电流的增大呈现先增大后减小的规律,这与器件的工作状态密切相关。功率老化试验后,高输入偏置电流条件下的低频噪声有所增大,这归因于电应力诱发的有源区缺陷。高温老化试验后,整个器件线性工作区条件下的低频噪声都明显增大,说明温度应力能够更多地激发器件内部的缺陷。相对于1/f噪声幅度参量,低频噪声宽带噪声电压参量可以更灵敏准确地进行器件可靠性表征。     

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.     

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.     

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.     

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.     

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.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.