磷化铟基高电子迁移率晶体管欧姆接触工艺

针对磷化铟(InP)基高电子迁移率晶体管(HEMT),进行了Ni/Ge/Au和Ni/Ge/Au/Ge/Ni/Au两种金属结构快速退火(10～40s)和长时间合金(10min)的实验.通过研究比较,得到了更适用于InP基HEMT器件制作的合金方法.利用Ni/Ge/Au/Ge/Ni/Au结构,在270℃下合金10min形成了典型值0.068Ω·mm的接触电阻.     

InAlAs/InGaAs/InP HEMT欧姆接触研究

应用Au/Ge/Ni系金属在InAlAs/InGaAs/InP HEMT上成功制作了良好的合金欧姆接触。采用WN和Ti双扩散阻挡层工艺优化欧姆接触,在样品上获得了最低9.01×10-8Ω.cm2的比接触电阻,对应的欧姆接触电阻为0.029Ω.mm。同时,在模拟后续工艺环境的20min250°C热处理后,器件的欧姆接触性能无显著变化,表明其具有一定的温度稳定性。     

InAs/InP量子点激光器中欧姆接触合金层特性研究

合金层与InAs/InP量子点激光器的接触电阻对激光 器的性能有很大影响,而接触电阻的 大小与合金材料、退火温度和退火时间有关。本文采用Au/Ni/Au/Ge做InAs/InP量子点激光 器的欧姆接触合金层,通过改变退 火温度和退火时间调节量子点激光器中接触电阻的阻值。实验发现,退火时间对接触电阻的 改变不 大,但是提高退火温度却能极大地降低接触电阻的阻值。实验获得了Au/Ni/Au/Ge 合金层与InAs/InP量子点激光器最佳欧姆接触条件,通过矩阵传输法测得相应接触电阻率为 1.34×10－6 Ω·cm²。在此条件下,制备激射中心波长为 1.577μm的多模量子点 激光器,室温下单面最大输出功率达到和超过39mW。     

InP基转移电子器件接触性能的优化研究

The effect of the annealing time and annealing temperature on Ni/Ge/Au electrode contacts deposited on the n-type InP contact layer has been studied using a circular transmission line model. The minimum specific contact resistance of 3.210 7 cm2was achieved on the low-doped n-type InP contact layer with a 40 s anneal at 425 ℃. In order to improve the ohmic contact and reduce the difficulty in the fabrication of the high doped InP epi-layer, the doping concentration in the InP contact layer was chosen to be 51018cm 3in the fabrication of transferred electronic devices. Excellent differential negative resistance properties were obtained by an electron beam evaporating the Ni/Ge/Au/Ge/Ni/Au composite electrode on an InP epi-layer with a 60 s anneal at 380 ℃.     

一种在砷化镓上形成欧姆接触的新型六层金属系统

研究了在砷化镓上欧姆接触形成机理,并提出了一种新型的欧姆接触六层金属系统(Ni/Ge/Au/Ge/Ni/Au).在n型GaAs样品上实验了在380～460℃合金温度和50～120 s合金时间下形成欧姆接触,在400℃、60 s下典型的欧姆接触值为2.1x10-7Ω·cm2,同时合金后表面形貌光滑、平整.     

Ge／Pt／Au,Ge／Au／Ni／Au—n型GaAs欧姆接触的对比研究

对用快速热合金方法（RTP）形成Ge/Pt/Au,Ge/Au/Ni/Au-n型GaAs欧姆接触进行了对比研究。实验结果表明，在合金形貌和欧姆接触特性兼顾的情况下，Ge/Pt/Au和Ge/Au/Ni/Au有不同的“温度－时间”窗口的接触电阻率。合金后，Auger能谱分析表明，Ge/Au/Ni/Au金属系统扩散进GaAs体内的净施主Ge浓度较高，因而接触电阻率较低。两种欧姆接触金属系统经高温存贮一定时间后，发现其接触电阻率都有所降低。     

基于Ti/Pt/Au欧姆接触金属系统的InP基HEMT器件

应用钛/铂/金(Ti/Pt/Au)金属系统在InP基HEMT制备工艺中形成了良好的欧姆接触,通过优化合金条件,获得了较低的欧姆接触电阻,并在此基础上对钛/铂/金欧姆接触形成机理进行了深入讨论。实验结果表明:在氮气气氛下进行温度300℃/30 s快速热退火后,得到欧姆接触最小电阻值为0.025Ω·mm。同时合金界面形态良好。制备出栅长1.0μm的InP基HEMT器件,测试结果表明器件具有良好的DC和RF特性,器件最大跨导(Gmmax)为672 mS/mm。饱和源漏电流IDSS为900 mA/mm,阈值电压为-0.8 V,单一的电流增益截止频率(fT)为40 GHz,最大晶振fmax为45 GHz。     

耿氏管的合金金属及正面反面工艺的研究

介绍了一种实现低成本、高功率、高散热性能耿氏管的工艺制备流程,利用分子束外延生长技术（MBE）在高掺杂的InP衬底上生长n n+型的一致性掺杂外延结构,在外延结构正面利用电子束蒸发Ge/Au/Ni/Au作为器件阴极和电镀金制备作为散热层,背面通过化学湿法腐蚀形成台面（MESA）。在不同的温度下进行了退火对比实验,研究了阴极合金形成良好欧姆接触的温度条件。结果表明:退火温度为450 ℃时形成的金属电极的接触效果最好。关于耿氏管的正面反面制备工艺简便易行,利用Ge/Au/Ni/Au制备金属电极得到了良好的欧姆接触性能,用氯基溶液进行了湿法腐蚀实验得到了较好的垂直台面（MESA）。该制备方法有望实现优良性能的耿氏器件。     

In0.53Ga0.47As/InP高速光电二极管材料生长及光电性能

利用低压MOCVD技术制备PIN结构的InP基InGaAs外延材料。采用分层吸收渐变电荷倍增(SAGCM)结构,通过两次Zn扩散、多层介质膜淀积、Au/Zn p型欧姆接触、Au/Ge/Ni n型欧姆接触等标准半导体平面工艺,设计制造正入射平面In_(0.53)Ga_(0.47)As/InP雪崩光电二极管器件。该器件采用与InP衬底晶格匹配的In_(0.53)Ga_(0.47)As材料做吸收层,InP材料做倍增层,同时引入InGaAsP梯度层。探测器件光敏面直径50μm,器件测试结果表明该器件光响应特性正常,击穿电压约43 V,在低于击穿电压3 V左右可以得到大约10 A/W的光响应度,在0 V到小于击穿电压1 V的偏压范围内,暗电流只有1 nA左右。光电二极管在8 GHz以下有平坦的增益,适用于5 Gbit/s光通信系统。     

Au/n-InP接触的热反应特性

研究了离子束溅射制备的Au /n-InP欧姆接触在退火前后的界面特性.400 ℃ 10 min退火后,比接触电阻比退火前降低了约两个数量级.利用俄歇电子能谱(AES)和X射线光电子能谱(XPS)研究了接触的表面和界面的冶金性质.实验结果表明在室温下InP中的In就可以扩散到接触的表面,退火后Au的价态升高,AuxIny合金中In的含量增加.退火后,在接触与n-InP的界面产生一个P聚集区,同时Au与InP反应生成Au2P3,金属-InP界面Au2P3的生成是比接触电阻降低的原因.     

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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