碲锌镉晶体常用腐蚀剂的坑形特性研究

大面积、高质量碲锌镉单晶是制备碲镉汞红外焦平面器件的理想衬底材料，而腐蚀法是常用的揭示碲锌镉晶体缺陷和评价晶体质量的方法之一。对碲锌镉晶体常用的Nakagawa、Everson、EAg1和EAg2四种腐蚀剂在碲锌镉材料（111）晶面上的腐蚀坑坑形进行了研究，结果发现，EAg2腐蚀剂在（111）B面上的腐蚀坑为平底坑，Everson腐蚀剂在 (111)B面上产生的腐蚀坑包括平底坑和带有不同倾斜方向坑底的三角锥形坑，进一步的研究还表明，三角锥形坑并未沿着坑底的倾斜方向向下延伸。实验中也首次观察到了EAg腐蚀剂的黑白平底坑。对常用腐蚀剂的坑形特性研究，将有助于更好地利用腐蚀剂开展碲锌镉材料缺陷研究和晶体质量评价工作。     

碲锌镉材料腐蚀坑及其缺陷特性研究

跟踪观察了Everson腐蚀剂在碲锌镉晶体(111)B面形成的腐蚀坑的形貌特征和空间延伸特性,并分析了各种腐蚀坑所对应的缺陷的特征.研究表明:碲锌镉材料的腐蚀坑具有三角锥型坑、平底三角坑、彗星状腐蚀坑和不规则腐蚀坑4种类型,其中三角锥型坑的坑尖又有5种不同的空间取向.彗星状腐蚀坑、三角锥型坑和不规则腐蚀坑具有定向移动特性.这表明这类腐蚀坑所对应的缺陷与材料的位错相关,但其穿越深度都不超过18μm,即缺陷同时具有局域化的特性.没有观测到平底三角坑的空间延伸特性,其所对应的缺陷可能是材料中的微沉淀缺陷.研究还发现:对于不同样品,各类腐蚀坑的数量和比例可有很大差异.而且,有些腐蚀坑所揭示的缺陷在被观察位置已经消失.因此,简单地用腐蚀坑密度(EPD)来描述碲锌镉材料表面缺陷密度和性能是不准确的.     

(111)晶向碲锌镉晶片双面腐蚀的对比

通过对材料减薄,并采用红外透射显微镜观察的手段,实现了对A面和B面腐蚀坑的同时观察.结果发现采用标准腐蚀剂在同一晶片的(111)A和(111)B面上形成的腐蚀坑大都不存在对应关系,深度腐蚀的实验也发现,表面腐蚀坑所对应的缺陷只局限于10μm的表层内,这表明大部分腐蚀坑所对应的不是通常认为的穿越位错.进一步分析的结果表明,不同腐蚀剂形成的腐蚀坑所对应的缺陷有可能是不同类型的位错,甚至也可能起源于微沉淀物,通常将碲锌镉材料的腐蚀坑所对应的缺陷简单地归结为材料的位错是缺乏实验依据的.     

(112)B碲锌镉衬底表面Everson腐蚀坑与材料缺陷的关系

通过研究碲锌镉衬底(112)B面缺陷腐蚀坑和(111)B面缺陷腐蚀坑之间的关系,揭示了(112)B面腐蚀坑与材料缺陷之间的关系。结果显示,Everson腐蚀剂在碲锌镉材料(112)B面上揭示的棒状腐蚀坑起源于材料中的体缺陷,或由延伸缺陷腐蚀坑在缺陷终止后演变而成,三种典型形状的锥形腐蚀坑分别来自延伸方向为110、112和123的延伸缺陷。研究结果同时显示,Everson腐蚀剂对部分取向的延伸缺陷所形成的腐蚀习性面在(112)B表面不能构成锥形腐蚀坑,通过观察(112)B面锥形坑随腐蚀深度发生横向移动的方向,进一步证实Everson腐蚀剂只能揭示延伸方向位于(112)极图上[011]和[101]连线附近区域的延伸缺陷。基于上述实验结果,文章进一步讨论了(112)B面Everson腐蚀坑密度与材料缺陷密度的关系,其结果将有助于碲镉汞分子束外延识别源自衬底的材料缺陷,并对碲锌镉(112)B衬底的质量进行更好的控制。     

(111)晶向碲锌镉晶片双面腐蚀的对比

通过对材料减薄，并采用红外透射显微镜观察的手段，实现了对A面和B面腐蚀坑的同时观察.结果发现采用标准腐蚀剂在同一晶片的（111) A和（111) B面上形成的腐蚀坑大都不存在对应关系，深度腐蚀的实验也发现，表面腐蚀坑所对应的缺陷只局限于10μm的表层内，这表明大部分腐蚀坑所对应的不是通常认为的穿越位错. 进一步分析的结果表明，不同腐蚀剂形成的腐蚀坑所对应的缺陷有可能是不同类型的位错，甚至也可能起源于微沉淀物，通常将碲锌镉材料的腐蚀坑所对应的缺陷简单地归结为材料的位错是缺乏实验依据的.     

碲锌镉衬底表面处理研究

主要从碲锌镉表面处理工艺及表面位错缺陷揭示两个方面对碲锌镉衬底的表面处理研究进行了详细介绍。从表面处理机理和工艺参数对衬底表面的影响两个方面介绍了机械研磨、机械抛光、化学机械抛光以及化学抛光4种表面处理工艺。同时，介绍了能揭示碲锌镉不同晶向表面的位错缺陷的Everson、Nakagawa及EAg三种化学腐蚀液。     

中国电科11所碲镉汞薄膜材料制备技术进展

碲镉汞材料具有响应速度快、量子效率高、带隙连续可调等优点,广泛应用于红外探测领域,本文报道了近年来中国电科11所在碲镉汞薄膜材料制备方面的技术进展。在碲锌镉衬底材料制备方面,已突破135mm碲锌镉晶体生长技术,碲锌镉衬底平均位错腐蚀坑密度(EPD) <1×104cm-2,具备了80mm×80mm规格碲锌镉衬底的批量生产能力。在液相外延碲镉汞薄膜制备方面,富碲水平液相外延碲镉汞薄膜平均位错腐蚀坑密度EPD<4×104cm-2,具备80mm×80mm规格碲镉汞薄膜的制备能力;富汞垂直液相外延实现高质量双层异质结碲镉汞薄膜材料批量化制备,该种材料的半峰宽(FWHM)控制在(20～40)arcsec范围内,碲镉汞薄膜厚度极差≤±06μm。在分子束外延碲镉汞薄膜方面,实现了6 in硅基碲镉汞材料制备,组分标准偏差≤00015,表面宏观缺陷密度≤100cm-2;碲锌镉基碲镉汞材料已具备50mm×50mm制备能力,组分标准偏差为0002,厚度标准偏差为0047μm。从探测器验证结果来看,基于富碲水平液相外延碲镉汞薄膜实现了1 k×1 k、2 k×2 k等规格红外焦平面探测器的工程化制备;采用双层异质结碲镉汞薄膜实现了高温工作、长波及甚长波探测器的制备;使用分子束外延制备的碲镉汞薄膜实现了27 k×27 k、54 k×54 k、8 k×8 k等规格红外焦平面探测器研制,在宇航领域有巨大的应用潜力。     

HgCdTe外延材料的缺陷腐蚀特性

通过对Schaake和Chen腐蚀剂在HgCdTe外延材料(111)B面腐蚀坑特性的研究,揭示了HgCdTe液相外延材料中的缺陷特征及其密度分布规律.深度腐蚀实验显示外延材料中确实存在着通常认为的具有定向穿越特性的穿越位错.将两种腐蚀剂作用于同一样品后发现,Schaake和Chen腐蚀剂形成的具有穿越特性的腐蚀坑有一一对应的关系.除了穿越位错外,在两种腐蚀方法揭示出的腐蚀坑中都还存在着一种不具备穿越特性的腐蚀坑,两者在密度分布以及界面处密度增值方面具有相同的特性,但前者在宏观缺陷附近密度出现明显的增值,而后者则没有出现类似的现象.     

HgCdTe外延材料的缺陷腐蚀特性

通过对Schaake和Chen腐蚀剂在HgCdTe外延材料(111)B面腐蚀坑特性的研究,揭示了HgCdTe液相外延材料中的缺陷特征及其密度分布规律.深度腐蚀实验显示外延材料中确实存在着通常认为的具有定向穿越特性的穿越位错.将两种腐蚀剂作用于同一样品后发现,Schaake和Chen腐蚀剂形成的具有穿越特性的腐蚀坑有一一对应的关系.除了穿越位错外,在两种腐蚀方法揭示出的腐蚀坑中都还存在着一种不具备穿越特性的腐蚀坑,两者在密度分布以及界面处密度增值方面具有相同的特性,但前者在宏观缺陷附近密度出现明显的增值,而后者则没有出现类似的现象.     

昆明物理研究所大面积水平推舟液相外延碲镉汞薄膜技术进展

报道了近年来昆明物理研究所在富碲水平推舟液相外延碲镉汞外延薄膜制备技术方面的进展。2019年以来,突破了?120 mm碲锌镉晶体定向生长技术,使碲锌镉衬底沉积相和夹杂相密度≤5×103 cm－2,位错腐蚀坑密度（EPD）≤4.0×104 cm－2,?120 mm（111）晶圆衬底的Zn组份分布极差≤0.36%。基于碲锌镉衬底技术的进步,液相外延碲镉汞薄膜的最大生长尺寸达到了70 mm×75 mm,薄膜位错腐蚀坑密度均值为5×104 cm－2,X射线双晶回摆曲线半峰宽（DCRC-FWHM）≤35 arcsec,部分可控制到25 arcsec以下;50 mm×60 mm尺寸长波碲镉汞薄膜的厚度极差≤±1.25 μm,室温截止波长极差≤±0.1 μm,中波碲镉汞薄膜相应指标分别为≤±1 μm、≤±0.05 μm。材料技术的进展促进了制冷型碲镉汞探测器产能提升和成本的降低,也支撑了高性能长波/甚长波探测器、高工作温度（HOT）探测器以及2048×2048、4096×4096等甚高分辨率高性能探测器的研制。     

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.     

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.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

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     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

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正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its