碲镉汞p-on-n长波异质结探测器材料的制备研究

报道了碲镉汞p+-on-n长波双层异质结材料和异质结台面器件的研究结果,重点研究了p+-on-n型双层异质结材料制备技术。通过水平滑舟富碲液相外延生长的方法在碲锌镉衬底上原位生长In掺杂碲镉汞n型吸收层材料,然后再采用富汞垂直液相外延技术制备p型As原位掺杂的碲镉汞cap层材料,从而获得p+-on-n型双层异质结材料,并通过湿法腐蚀、台面刻蚀以及钝化等工艺得到碲镉汞 p+-on-n长波异质结台面型器件。p+-on-n异质结器件结构可以有效克服少子寿命偏低等问题,在长波及甚长波波段具有更低的暗电流和更高的R0A值,这对于解决目前长波碲镉汞红外探测器暗电流大、结阻抗低的问题,提高长波及甚长波波段碲镉汞红外焦平面器件的性能具有重要的意义。     

微电子学、集成电路

TN42005040348碲镉汞p+-on-n长波异质结探测器的研究/叶振华,吴俊,胡晓宁,巫艳,王建新,李言谨,何力(中国科学院上海技术物理研究所材料器件中心)//红外与毫米波学报.―2004,23(6).―423～426.报道了HgCdTe p+-on-n长波异质结焦平面器件的研究结果.采用由分子束外延(MBE)和原位掺杂技术生长的P+-on-n异质结材料,通过湿法腐蚀、台面钝化、台面金属化、铟柱制备和互连等工艺,得到了HgCdTe p+-on-n长波异质结焦平面器件.根据,I-V实验结果和暗电流理论,拟合计算和分析了各种暗电流机制对器件性能的影响.且获得了器件的响应光谱和探测率。图…     

低暗电流高温工作碲镉汞红外探测器制备技术

报道了与传统的n-on-p结构相比具有更低暗电流的p+-on-n型碲镉汞红外探测器的研究进展。通过水平滑舟富碲液相外延生长的方法在碲锌镉衬底上原位生长In掺杂碲镉汞n型吸收层材料,然后再分别采用As离子注入技术和富汞垂直液相外延技生长技术实现了P型As外掺杂的p+-on-n型平面型和双层异质结台面型两种结构的芯片制备。碲镉汞探测器的主要缺点是需要低温制冷,期望碲镉汞探测器在不降低性能的前提下具有更高的工作温度(High Operating Temperature,HOT),成为红外探测器技术发展的主要方向。本文对基于标准的n-on-p(Hg空位)掺杂工艺及新研制的p-on-n型As离子注入及异质结制备技术的探测器进行了高温性能测试,测试结果表明采用p-on-n型的碲镉汞探测器能够实现更高的工作温度。     

分子束外延碲镉汞探测器的变结面积I-V测试研究

碲镉汞红外探测器的表面钝化处理对器件暗电流有较大影响,决定了器件的探测性能。为了研究表面钝化层不同生长方式对暗电流的抑制效果,使用分子束外延(Molecular Beam Epitaxy, MBE)系统在Si基衬底上生长碲镉汞材料,分别通过磁控溅射和原位钝化方法生长CdTe/ZnS钝化膜层。采用半导体工艺在碲镉汞材料上制备了变面积光伏探测器。通过测试不同钝化膜层器件的暗电流,分析零偏电阻和面积乘积(R₀A)与周长面积之比(p/A)的关系。结果表明,磁控溅射生长钝化层的Si基碲镉汞器件存在较大的隧穿电流,而原位钝化生长钝化层的Si基碲镉汞器件能更有效地抑制表面漏电流。拟合器件R₀A因子随PN结面积的变化,得出原位生长钝化层的器件具有更好的钝化效果。变面积器件的制备和测试能够有效且直观地反映器件性能。     

软脆碲锌镉衬底的新型化学抛光技术研究

碲锌镉(CdZnTe)是液相外延碲镉汞(HgCdTe)薄膜的最佳衬底材料。获得高质量的CdZnTe衬底表面对于提升红外探测器的性能有着十分重大的意义。针对CdZnTe表面加工技术进行了研究,开发出一种新的化学抛光技术,使得抛光后的CdZnTe表面粗糙度Ra可达0.3 nm。     

CdZnTe(211)B衬底对MBE外延碲镉汞材料的影响分析

碲锌镉 CdZnTe（211）B 衬底广泛应用于碲镉汞（HgCdTe）分子束外延生长,其性能参数在很大程度上决定了碲镉汞分子束外延材料的质量。主要讨论了 CdZnTe（211）B 衬底几个关键性能参数对碲镉汞外延材料的影响,包括 Zn 组分及均匀性、缺陷（位错、孪晶及晶界和碲沉淀）以及表面状态（粗糙度和化学组成）,并且分析了对 CdZnTe（211）B 衬底进行筛分时各性能参数的评价方法和指标。     

HgCdTe/CdZnTe晶格失配与X光衍射貌相的关系研究

文章采用富Te水平推舟液相外延工艺在CdZnTe衬底上生长了HgCdTe外延薄膜.研究了外延薄膜/衬底晶格失配度、X光衍射貌相、红外焦平面器件探测率三者之间的关系.对于HgCdTe外延层的X光衍射貌相我们将其大致分为五类,分别是Crosshatch貌相、混合貌相、均匀背景貌相、Mosaic貌相以及由衬底质量问题引起的沟壑状貌相,采用Crosshatch貌相和混合貌相材料所制备的红外焦平面器件,平均来说其探测率(D*)较高.X射线双轴衍射的实验结果表明,当外延层与衬底的晶格失配度为～0.03%时,外延层会呈现明显的Crosshatch貌相;而当失配度减小时,会逐渐呈现出混合貌相、均匀背景貌相、直至失配度为负值时呈现Mosaic貌相.因此,对于特定截止波长的HgCdTe焦平面器件,可以通过控制HgCdTe/CdZnTe之间的失配,生长出符合我们要求的貌相的碲镉汞外延材料,从而来提高焦平面器件的性能.     

大面阵短波碲镉汞红外焦平面器件研究

随着红外焦平面技术的发展,大面阵红外焦平面器件在遥感、气象、资源普查和高分辨对地观测卫星上得到了广泛应用。因此,基于第三代红外焦平面技术的超大规模焦平面器件成为国内外研究热点。文中介绍了昆明物理研究所采用n-on-p技术路线成功研制的短波（Short Wave, SW） 2 k×2 k（18 μm,像元中心距）碲镉汞红外焦平面器件。短波2 k×2 k碲镉汞红外焦平面器件突破了大尺寸碲锌镉（CdZnTe）衬底制备和大面积液相外延薄膜材料生长技术,衬底尺寸由Φ75 mm增加到Φ90 mm,获得了高度均匀的大面积碲镉汞（HgCdTe）薄膜材料。通过大面阵器件工艺、大面阵倒装互连等技术攻关,最终获得了有效像元率大于99.9%、平均峰值探测率(D*)大于4×1012 (cm·Hz1/2)/W、暗电流密度在1 nA/cm2的高性能短波2 k×2 k（18 μm）碲镉汞红外焦平面器件。     

甚长波碲镉汞光伏探测器伏安特性分析

分析了注入同质结N on P和液相外延异质结P on N碲镉汞甚长波红外探测器在不同工作温度下的I V特性,并对R V特性进行了仿真计算,对比了扩散电流、产生-复合电流、表面漏电流、带间隧穿电流和缺陷辅助隧穿电流等暗电流对两种器件R V特性的不同影响。     

基于三代红外探测器的一种新型材料——硒镉汞

介绍了一种新型的红外探测器材料硒镉汞(HgCdSe)的最新研究进展,以及其所使用的衬底材料ZnTe/Si(211)和GaSb(211)的最新研究情况.通过与碲镉汞(HgCdTe)材料的对比可看出,硒镉汞材料的性能优良,比碲镉汞性能更稳定、更易生长,并且有较为成熟的衬底材料,辅以在同是汞基材料-碲镉汞上面所取得的生长经验,有望成为替代碲镉汞的下一代红外探测材料,极具应用前景.     

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.     

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.     

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.     

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.     

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.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-