一种简便有效的多孔硅后处理新方法

本文报道了一种简便有效的多孔硅（ＰＳ）后处理新方法，即在（ＮＨ４）２Ｓ／Ｃ２Ｈ５ＯＨ溶液中浸泡ＰＳ，并用紫外光辐照激发．后处理ＰＳ的光致发光（ＰＬ）强度约为未经处理的５倍；样品处理后的ＰＬ峰值９０ｍｉｎ内随激光连续激发时，在大气中呈现先指数衰减后线性增长，在真空（约１Ｐａ）中却呈现一直衰减到一个稳定值的新特点．通过样品的傅里叶变换红外吸收（ＦＴＩＲ）谱的测试与分析，表明后处理在样品表面产生了ＳｉＨ（Ｏ３）、Ｓｉ－Ｏ－Ｓｉ和Ｓｉ３Ｎ４三种提高ＰＳ的ＰＬ强度和稳定性的优质钝化膜     

硅表面清洗对热氧化13nm SiO_2可靠性的影响

实验研究表明热生长１３ｎｍ薄ＳｉＯ２的可靠性同氧化前硅表面清洗处理方法有很大关系．氧化前稀ＨＦ酸及ＨＦ／乙醇漂洗不会提高热氧化薄ＳｉＯ２的可靠性;氧化前用ＮＨ４ＯＨ／Ｈ２Ｏ２／Ｈ２Ｏ（０．０５∶２∶５）溶液清洗形成化学预氧化层对提高薄ＳｉＯ２可靠性很有效;用Ｈ２ＳＯ４／Ｈ２Ｏ２（３∶１）溶液清洗形成预氧化层的改善作用也较明显,在之前增加比例为０．０５∶２∶５或１∶２∶５的ＮＨ４ＯＨ／Ｈ２Ｏ２／Ｈ２Ｏ溶液清洗和稀ＨＦ酸漂洗效果更好．另外,薄栅介质抗电离辐射性能和抗热电子损伤能力同氧化前形成化学预氧化层的清洗     

经Al_2O_3与SiO_x钝化的多孔硅及其光致发光特性

在一定偏压下用ＡｌＣｌ３＋Ｃ２Ｈ５ＯＨ＋Ｈ２Ｏ混合液对多孔硅进行了后处理．经过处理的多孔硅与未经处理的多孔硅相比,其发光强且稳定．通过对样品进行红外吸收谱的测试和分析,指出在后处理样品表面形成的Ａｌ２Ｏ３与ＳｉＯｘ结构是多孔硅发光增强和稳定性得到提高的原因．     

多孔硅的氢化、氧化与光致发光

对于刚阳极氧化完的，阳极氧化后紧接着在Ｈ２Ｏ２中光照处理的及长期存放（１０个月）的三种多孔硅样品进行了持续激光照射，不断监视它们的光致发光（ＰＬ）与富利埃变换红外（ＦＴＩＲ）吸收光谱，并在最后对它们作了Ｘ射线光电子能谱（ＸＰＳ）测量，以确定它们所含氧化硅的情况．得出如下几条结论：（１）氢对多孔硅表面的钝化是不稳定的．（２）Ｓｉ—Ｈ键不是发光所必须的．（３）氧对多孔硅表面的钝化是稳定的，纳米硅周围氧化层的存在及其特性对于稳定的多孔硅可见光发射是至关重要的．对激光照射下多孔硅发光的退化提出了新的解释．     

多孔硅的形成与光致发光谱

介绍了用阳极氧化腐蚀形成多孔硅的工艺，并分析了它的微结构，实验测定了多孔硅光致发光谱（ＰＬ），由ＰＬ谱的峰值位于可见光区，不同于Ｓｉ的带隙能量；用纳米量子限制效应（Ｑ－ＣＥ），解释了多孔硅中进入量子线中电子和空穴能量增量为ΔＥｃ和ΔＥｖ，于是多了孔硅有效带宽成为Ｅ＝Ｅ。＋ΔＥ。而Ｅ。是Ｓｉ的带宽为ｌ．０８ｅＶ，ΔＥｃ和上ΔＥｖ分别为ｈ２／４ｍｅｑ２和ｈ２／４ｍｈｑ２，由此计算与实验结果一致。     

Fe~＋和H~＋注入引起的Si／SiO_2界面重构现象

针对Ｓｉ－ＳｉＯ２过渡区对于离子注入较为敏感的特点，用１．２ＭｅＶ，剂量１×１０１０ｃｍ－２的Ｆｅ＋和Ｈ＋先后注入ＳｉＯ２－Ｓｉ样品，并用ＸＰＳ技术重点分析了Ｓｉ－ＳｉＯ２界面附近硅的化学结构、组分的变化。结果表明，在界面附近，除了Ｓｉ４＋，Ｓｉ０价态，还存在明显的Ｓｉ２＋价态。这和注入Ｈ＋产生的高温退火以及Ｓｉ—Ｓｉ键或Ｓｉ—Ｈ键的形成有关。     

硅表面清洗对7nm热SiO_2栅介质可靠性的影响

实验研究了硅表面清洗方式对７ｎｍ热氧化ＳｉＯ２栅介质可靠性的影响．结果表明,稀ＨＦ酸漂洗后ＲＣＡ清洗时降低ＳＣ１（ＮＨ４ＯＨ／Ｈ２Ｏ２／Ｈ２Ｏ）温度对提高栅介质可靠性有利,但仍不如用ＳＣ２（ＨＣｌ／Ｈ２Ｏ２／Ｈ２Ｏ）或Ｈ２ＳＯ４／Ｈ２Ｏ２清洗效果好．稀ＨＦ酸漂洗后用Ｈ２ＳＯ４／Ｈ２Ｏ２清洗得到的栅介质不仅表现出优良的击穿电场分布特性和击穿电荷分布特性,抗热电子损伤能力也比较强     

注C~＋硅多孔结构的蓝光发射

对单晶硅进行Ｃ＋注入，注入能量为５０ｋｅＶ，注入剂量为１e１５～１e１７／ｃｍ２．在Ｎ２中经９５０℃退火１小时后，注入层形成尺寸为１～３μｍ的β－ＳｉＣ沉淀．进而采用电化学腐蚀方法将样品制成多孔结构．在紫外光激发下，样品可以发射强度较大的蓝光，光强是通常多孔硅的数倍以上，谱峰处于４８０ｎｍ和５０５ｎｍ附近．这一方法简便有效地实现了硅基材料的蓝光发射．     

K对H_2O在Si（001）表面上吸附的影响

在Ｓｉ（００１）－２×１表面上沉积碱金属Ｋ，接着在室温下吸附一定量的Ｈ２Ｏ，光电子谱证明：Ｋ的存在有促进Ｈ２Ｏ分解和使Ｓｉ氧化的作用．但其作用是局域在Ｋ原子附近的．     

注氮硅中光致发光现象及其机制的研究

通过能量为１００ｋｅＶ，剂量为１×１０１８ｃｍ－２的Ｎ＋注入到硅基体中，经１０００～１２００℃之间快速退火后，形成了含氧的硅与氮化硅镶嵌结构的薄膜层．在室温下观测到主要来自于４５ｎｍ表面层的能量分别为：３．３ｅＶ、３．０ｅＶ、２．８ｅＶ和２．２ｅＶ的光致发光．通过ＸＰＳ、ＡＥＳ的分析，确认了由于氧的插入，样品中Ｎ－Ｓｉ－Ｏ缺陷，Ｓｉ／ＳｉＯ２界面发光中心，分别是引起３．０ｅＶ和２．２ｅＶ的光致发光的主要原因．     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

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.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

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.     

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.