高阻值Cd_(1-x)Zn_xTe晶体的生长及其性能测试

通过适当的工艺措施,采用Bridgman法生长了直径为30mm的X射线及γ射线探测器级的Cd0 9Zn0 1Te晶锭.测试结果表明:该晶锭结晶质量良好,位错密度低,成分均匀,杂质含量低,红外透过率和电阻率都十分接近本征Cd0 9Zn0 1Te的值.并从晶体的生长特性、缺陷和杂质的角度,分析了生长高性能晶体的条件,研究了生长Cd1-xZnxTe晶体的x值与缺陷和杂质浓度之间的关系     

高阻值Cd1-xZnxTe晶体的生长及其性能测试

通过适当的工艺措施,采用Bridgman法生长了直径为30mm的X射线及γ射线探测器级的Cd0.9Zn0.1Te晶锭.测试结果表明:该晶锭结晶质量良好,位错密度低,成分均匀,杂质含量低,红外透过率和电阻率都十分接近本征Cd0.9Zn0.1Te的值.并从晶体的生长特性、缺陷和杂质的角度,分析了生长高性能晶体的条件,研究了生长Cd1-xZnxTe晶体的x值与缺陷和杂质浓度之间的关系.     

改进的垂直布里奇曼法生长CdZnTe晶体中的成分偏离现象

采用多种测试方法,对改进的垂直布里奇曼法生长Cd0.96Zn0.04Te晶体中的成分偏离标准化学计量比现象及其对晶体性能的影响进行了研究.X射线能谱成分测试表明,在晶锭的头部即初始结晶位置,(Cd Zn)/Te比大于1;而在中部及末端,小于1.表明这种方法生长的CZT晶体仍然存在对标准化学计量比的偏离现象,开始结晶是在富Cd熔体中,生长至中后段则是在富Te条件下进行的.PL谱测试表明,富Cd的晶片内存在大量Te空位,严重富Te的晶片内Cd空位及其杂质复合体等引起的缺陷密度显著增加.晶体红外透过率测试结果表明,接近化学计量配比的CZT晶片具有高的红外透过率.     

改进的垂直布里奇曼法生长CdZnTe晶体中的成分偏离现象

采用多种测试方法,对改进的垂直布里奇曼法生长Cd0.96Zn0.04Te晶体中的成分偏离标准化学计量比现象及其对晶体性能的影响进行了研究.X射线能谱成分测试表明,在晶锭的头部即初始结晶位置,(Cd+Zn)/Te比大于1;而在中部及末端,小于1.表明这种方法生长的CZT晶体仍然存在对标准化学计量比的偏离现象,开始结晶是在富Cd熔体中,生长至中后段则是在富Te条件下进行的.PL谱测试表明,富Cd的晶片内存在大量Te空位,严重富Te的晶片内Cd空位及其杂质复合体等引起的缺陷密度显著增加.晶体红外透过率测试结果表明,接近化学计量配比的CZT晶片具有高的红外透过率.     

高阻CdZnTe晶体的退火处理

获得高电阻率的、完整性好的 Cd Zn Te晶体是研制高性能的 Cd Zn Teγ射线探测器的关键 .运用热力学关系估算了 Cd1 - x Znx 熔体平衡分压 ,尝试以 Cd1 - x Znx 合金源替代 Cd源进行 Cd0 .8Zn0 .2 Te晶片的热处理 ,研究了退火对 Cd0 .8Zn0 .2 Te晶片质量的影响 .结果表明 :在 10 6 9K下用 Cd0 .8Zn0 .2 合金源 (PZn=0 .12 2e5 Pa和 PCd=1.2 0e5 Pa)对 Cd0 .8Zn0 .2 Te晶片退火 5天以上 ,可提高晶体电阻率一个数量级和晶体红外透过率 10 %以上 ,并可消除或减小晶片中的 Te沉淀 ,同时避免了 Zn的损失 ,改善 Zn的径向分布 .可见 ,采用 Cd1 - x Zn     

ZnCdTe衬底上HgCdTe分子束外延的位错密度

报道了用 MBE的方法 ,在 Zn Cd Te衬底上制备 Hg Cd Te薄膜的位错密度研究结果。研究发现Hg Cd Te材料的位错密度与 Zn Cd Te衬底的表面晶体损伤、Hg Cd Te生长条件以及材料组分密切相关。通过衬底制备以及生长条件的优化 ,在 Zn Cd Te衬底上生长的长波 Hg Cd Te材料 EPD平均值达到 4.2× 1 0 5cm- 2 ,标准差为 3 .5× 1 0 5cm- 2 ,接近 Zn Cd Te衬底的位错极限。可重复性良好 ,材料位错合格率为 73 .7%。可以满足高性能Hg Cd Te焦平面探测器对材料位错密度的要求     

高阻碲锌镉单晶体的生长及其性能观测

报道了采用富Cd原料的无籽晶垂直布里奇曼法生长高阻碲锌镉Cd0.8Zn0.2Te(CZT)单晶体的新工艺,对所生长的晶体作了X射线衍射分析、红外透过率测试、光吸收截止波长测量及电学性能测试.晶体在4400～450cm-1范围内的红外透过率达到50%,截止吸收波长为787.6nm,带隙为1.574eV,室温电阻率达到2×1010Ω·cm,已接近本征Cd0.8Zn0.2Te半导体的理论值.用该晶体制作的核探测器在室温下对241Am和109Cd放射源均有响应,并获得了比较好的241Am-59.5keV吸收谱.结果表明改进的方法是一种生长室温核辐射探测器应用的高阻CZT单晶体的简便有效的新方法.     

高阻碲锌镉单晶体的生长及其性能观测

报道了采用富Cd原料的无籽晶垂直布里奇曼法生长高阻碲锌镉Cd0.8Zn0.2Te(CZT)单晶体的新工艺,对所生长的晶体作了X射线衍射分析、红外透过率测试、光吸收截止波长测量及电学性能测试.晶体在4400～450cm-1范围内的红外透过率达到50%,截止吸收波长为787.6nm,带隙为1.574eV,室温电阻率达到2×1010Ω·cm,已接近本征Cd0.8Zn0.2Te半导体的理论值.用该晶体制作的核探测器在室温下对241Am和109Cd放射源均有响应,并获得了比较好的241Am-59.5keV吸收谱.结果表明改进的方法是一种生长室温核辐射探测器应用的高阻CZT单晶体的简便有效的新方法.     

退火对CdZnTe晶体质量的影响

我们用红外透射光谱和X射线双晶衍射等，研究了退火对CdZnTe晶体质量的影响．结果表明，在Cd气氛中，700℃，退火5小时以上，能大量地去除晶片中的Te沉淀，提高其红外透射比；同时，退火也导致了晶片表面的损伤，损伤层为50～130μm．表面结构损伤的原因是，（1）Cd气氛中退火，CdZnTe晶体表面的Zn损失；（2）退火过程中，吸附在沉淀物周围的杂质，尤其是快扩散杂质，将随着沉淀相的消失而迁移到晶体的表面，从而破坏了表面的晶体结构．退火后，磨去损伤层，可将聚集在表面的这些杂质除去，更有利于外延生长或器件制备．     

高阻CdZnTe晶体的退火处理

获得高电阻率的、完整性好的CdZnTe晶体是研制高性能的CdZnTe γ射线探测器的关键.运用热力学关系估算了Cd1-xZnx熔体平衡分压,尝试以Cd1-xZnx合金源替代Cd源进行Cd0.8Zn0.2Te晶片的热处理,研究了退火对Cd0.8Zn0.2Te晶片质量的影响.结果表明：在1069K下用Cd0.8Zn0.2合金源（PZn=0.122×105Pa和PCd=1.20×105Pa）对Cd0.8Zn0.2Te晶片退火5天以上,可提高晶体电阻率一个数量级和晶体红外透过率10%以上,并可消除或减小晶片中的Te沉淀,同时避免了Zn的损失,改善Zn的径向分布.可见,采用Cd1-xZnx合金源代替Cd源控制进行CZT退火处理优于仅采用Cd源控制的退火处理.     

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.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

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.     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.