空位和填隙缺陷对半绝缘InP单晶性质的影响

利用电学测试、正电子寿命谱和X射线衍射技术研究了原生和退火处理后InP单晶的空位和填隙缺陷.在原生掺铁半绝缘InP单晶中含有空位缺陷,这些空位产生深能级电学补偿缺陷,降低材料的电学性能.经高温磷化铁气氛下退火处理非掺InP制备的半绝缘材料,空位被充分抑制,却含有一定浓度填隙缺陷.根据实验结果分析了填隙和空位缺陷对掺铁半绝缘InP单晶材料电学性质和热稳定性的影响.     

空位和填隙缺陷对半绝缘InP单晶性质的影响

利用电学测试、正电子寿命谱和X射线衍射技术研究了原生和退火处理后InP单晶的空位和填隙缺陷.在原生掺铁半绝缘InP单晶中含有空位缺陷,这些空位产生深能级电学补偿缺陷,降低材料的电学性能.经高温磷化铁气氛下退火处理非掺InP制备的半绝缘材料,空位被充分抑制,却含有一定浓度填隙缺陷.根据实验结果分析了填隙和空位缺陷对掺铁半绝缘InP单晶材料电学性质和热稳定性的影响.     

热退火对多晶硅特性的影响

为研究热退火对太阳电池用多晶硅的影响,在750～1150℃,N2和O2环境下分别对硅片进行热处理.用傅里叶红外光谱仪和准稳态光电导衰减法测量退火前后的氧碳含量和少子寿命的变化.为了比较,对有相同氧碳含量的直拉硅片进行同样处理.结果发现:在多晶和单晶片中氧碳含量下降很小,意味着没有氧沉淀产生,晶界对碳行为影响不大.多晶硅片在N2和O2环境下,850、950和1150℃下退火,少子寿命都有很大提高,并且在O2中退火比N2中退火少子寿命上升得更多,可能由于在高温退火时大量杂质扩散到晶界处,减少了复合中心.另外,间隙硅原子填充了空位或复合中心从而导致寿命提高.     

GaAs可饱和吸收体本征点缺陷的第一性原理计算与模拟

GaAs可饱和吸收体中的深能级缺陷(EL2缺陷)对其被动调Q性能有着重要的影响,因此有必要对EL2缺陷的微观结构及形成机理做进一步研究.用基于密度泛函理论的平面波赝势法首先对GaAs本征点缺陷(镓空位、砷空位、镓替代砷、砷替代镓、镓间隙、砷间隙)存在时的晶格结构进行优化,得到其稳定结构;然后通过各缺陷形成能的计算可得知...     

退火处理对0.5PZN-0.5PZT陶瓷弛豫性的影响

采用常规陶瓷工艺制备了Pb(Zn_(1/3)Nb_(2/3))_(0.5)(Zr_(0.5)Ti_(0.5))_(0.5)O_3 (0.5PZN-0.5PZT)铁电陶瓷,并在氧气氛下进行退火.运用XRD、直流电导率和介电温度谱测试氧气氛退火前后陶瓷相结构与电性能的变化,并对弛豫性与微结构的关系进行探讨.结果表明,氧气氛退火可有效补偿体系中的氧空位,降低四方相含量,材料的弛豫性显著增强.     

退火对钨酸镉晶体光谱性能影响的研究

研究了提拉法生长的钨酸镉单晶在真空与氧气氛中退火对晶体透过率、激发发射光谱和荧光寿命等的影响,结果表明:氧退火有利于提高晶体的透过率与光产额,并在一定程度上提高了蓝光发射比例,提高了该晶体的能量分辨率,这可能是氧退火使晶体的氧空位减少,导致晶体在340～440 nm由氧空位缺陷产生的吸收减弱所致.同时,氧退火有利于缩短晶体的荧光寿命,从而提高钨酸镉的时间分辨率.     

热退火对多晶硅特性的影响

为研究热退火对太阳电池用多晶硅的影响,在750～1150℃,N2和O2环境下分别对硅片进行热处理.用傅里叶红外光谱仪和准稳态光电导衰减法测量退火前后的氧碳含量和少子寿命的变化.为了比较,对有相同氧碳含量的直拉硅片进行同样处理.结果发现:在多晶和单晶片中氧碳含量下降很小,意味着没有氧沉淀产生,晶界对碳行为影响不大.多晶硅片在N2和O2环境下,850、950和1150℃下退火,少子寿命都有很大提高,并且在O2中退火比N2中退火少子寿命上升得更多,可能由于在高温退火时大量杂质扩散到晶界处,减少了复合中心.另外,间隙硅原子填充了空位或复合中心从而导致寿命提高.     

中子辐照氢气区熔硅单晶退火行为的正电子湮没研究

用正电子湮没寿命和多普勒加宽方法研究了中子辐照氢气区熔硅单晶的等时退火行为.观测到324±12ps的寿命组分是正电子在双空位湮没寿命,是主要的长寿命组分.450±14ps是正电子在四空位湮没寿命。324ps寿命组分在450℃附近退火消失后,它又以较高的强度在530—800℃的温度范围出现.对不同温度退火的晶体取得的基块寿命不是常数值而是随退火温度有规律的变化.这些异常的退火行为归结为中子辐照硅中所诱导的空位缺陷与氢的相互作用及其对晶格的影响.     

SI GaAS中S~+注入的电学特性

本文研究了经常规热退火和快速热退火后SIGaAs中S~+注入的电学特性.热退火后,GaAs中注入S~+的快扩散和再分布不决定于S~+或砷空位V_(AS)的扩散而决定于离子注入增强扩散.使用快速热退火方法能抑制注入S~+在GaAs中的增强扩散,明显减小S~+的再分布,可以获得适合于制造GaAs MESFET器件的薄有源层.     

n型SiC的Ni基欧姆接触中C空位作用的实验证明

通过在Si面p型4H-SiC外延层上使用P+离子注入来形成n阱.Ti和Ni依次淀积在有源区的表面,金属化退火后的XRD分析结果表明Ni2Si是主要的合金相.XEDS的结果表明在Ni2Si/SiC界面处存在一层无定型C.去除Ni2Si合金相与无定型C之后重新淀积金属,不经退火即可形成欧姆接触.同时,注入层的方块电阻Rsh从975下降到438Ω/□.结果表明,合金化退火过程中形成了起施主作用的C空位(VC).C空位提高了有效载流子浓度并对最终形成欧姆接触起到了重要作用.     

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.     

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.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm