磁控溅射ITO薄膜结构和性能的研究

利用中频脉冲磁控溅射工艺制备ITO薄膜,研究了在衬靶间距为60 mm、衬底温度为350℃、溅射功率为120 W、溅射气压为0.2 Pa的条件下,氧氩比(O2/Ar)、溅射时间对ITO薄膜表面形貌、膜厚、沉积速率及光电性能的影响。通过实验和分析,最终确定了在玻璃衬底上制备ITO薄膜的最佳氧氩比和溅射时间:氧氩比为0.4:40,溅射时间为45 min,获得了方阻为2.55Ω/□,电阻率为1.46×10-4Ω·cm,可见光范围内平均透过率为81.2%的薄膜。     

磁控溅射低阻ITO薄膜的气体参数优化

用直流磁控溅射系统在不同气压和氩氧流量比(V(Ar):V(O2),体积比)下制备铟锡氧化物(ITO)薄膜。测试了薄膜的方阻和透过率,得到不同沉积气压和V(Ar):V(O2)对薄膜电光特性的影响大小和趋势。X-射线衍射(XRD)测试表明ITO薄膜的晶粒尺寸随膜内氧的摩尔分数增加而增大,随氧气比例增加薄膜(400)晶向消失。优化参数为气压266.664 mPa,V(Ar):V(O2)=15:0,制备的ITO薄膜方阻为22Ω/□,在可见光区域平均透过率为85%。     

直流反应磁控溅射法制备锐钛矿TiO2薄膜

采用直流反应磁控溅射的方法，溅射高纯钛靶在玻璃衬底上制备了TiO2薄膜。用XRD测试了TiO2薄膜的结构，研究了工艺因素中衬底温度、溅射气压、氧氩气体流量比和退火温度对薄膜结构的影响。实验结果表明：衬底温度高于200℃、溅射气压不高于0．7Pa、氧氩流量比为1／4、退火温度为650℃时，锐钛矿TiO2薄膜更容易结晶。     

共溅射法制备ITO:Zr薄膜及其特性研究

采用ITO靶和Zr靶共溅射在玻璃衬底上沉积了ITO:Zr薄膜,研究了衬底温度、氧流量对ITO:Zr薄膜性能的影响.表征和对比了ITO:Zr薄膜晶体结构和表面粗糙度的变化ITO:Zr薄膜在低温生长时就可以得到良好的光电性能,衬底温度的提高显著改善了薄膜光电性能;一定范围的氧流量也可以改善薄膜的性能,但过量的氧却使得ITO:Zr薄膜的光性能变差.透射谱表明各参数的变化引起了明显的"Burstin Moss"效应.当优化溅射条件为工作气压0.5Pa、氧流量0.3 sccm、直流溅射功率45 W(ITO靶)和射频功率10 W(Z靶)、沉积速率8 nm/min和一定的衬底温度时,可以获得方阻10～20 Ω/sq和可见光透过率85%(含基底)以上的ITO:Zr薄膜.     

VOx薄膜的制备、电阻-温度特性及结构研究

VO2是一种热致相变材料.发生相变时,VO2的电阻、红外光透过率、反射率都会发生显著变化.采用直流反应磁控溅射法,通过改变氧氩比(O2:Ar)、工作气压、衬底温度等制备工艺参数,研究了工艺参数对VOx薄膜的结构、电阻-温度性能的影响.结果表明,当氧氩比为1.0:15、工作气压为2.0Pa时,制备的薄膜中VO2的含量较多;衬底温度为250℃时,制备的VOx薄膜的电阻一温度突变性能最佳.     

成膜与热处理参数对溅射沉积ITO 膜电性能的影响

采用了补氧直流磁控反应溅射工艺制备ITO膜，在不同基片加热温度和补氧流量下获得最低方块电阻值的最佳制备工艺。对制备的ITO薄膜进行了退火热处理，研究不同温度热处理后膜的方块阻值的变化。实验表明，对一定的基片加热温度，ITO膜的方块电阻与溅射气氛中的补氧流量有关，并存在一个最佳补氧的值，在该条件下制备ITO的方块电阻最小，在膜厚为40nm埃时仅有不到100Ω／□。影响溅射沉积ITO透明导电薄膜方阻的，除了溅射沉积时基片的烘烤温度和补氧流量外，还包括后期大气退火热处理的温度。     

制备工艺对ITO薄膜的电阻率及沉积速率的影响

采用射频磁控溅射法制备了氧化铟锡[ITO,In2O3:SnO2=90:10(质量比)]薄膜,详细探讨了溅射气氛氧氩体积比、溅射功率及溅射气压对ITO薄膜电阻率和沉积速率的影响。结果表明:溅射工艺参数对ITO薄膜电阻率和沉积速率的影响十分明显。随着氧氩体积比的增大,样品的电阻率显著增大,沉积速率下降;随着溅射功率的增加,ITO薄膜的电阻率先减小后略微增大,沉积速率上升;随着溅射气压升高,ITO薄膜的电阻率先减小后增大,当溅射气压增大到较大值时,ITO薄膜的电阻率又开始减小,而沉积速率则先上升后下降。     

氧流量对ITO和ITO∶Zr薄膜性能的影响

利用双靶共溅法在玻璃衬底上沉积了Zr掺杂ITO薄膜,对比研究了在不同氧流量下ITO和ITO∶Zr薄膜性能的变化.Zr的掺入促进薄膜晶化的同时也导致了(400)晶面取向的加强,ITO∶Zr比ITO薄膜具有较低的表面粗糙度.氧流量的上升降低了方阻和载流子浓度,ITO∶Zr薄膜具有更高的载流子浓度.一定范围的氧流量可以改善薄膜的可见光透过率,但过量的氧却使得薄膜的光学性能变差.通过直接跃迁的模型得出ITO∶Zr比ITO薄膜具有更宽的光学禁带.共溅法制备的ITO∶Zr薄膜比ITO薄膜表现出更好的光电性能.     

掺Sn的In2O3透明导电膜生长优先取向对其光电性能的影响

采用反应热蒸发法制备掺Sn的In2O3(ITO)透明导电膜,系统研究了ITO薄膜生长的优先取向对其光电性能的影响.结果表明,ITO薄膜(400)取向的优先生长对其透过率影响很小,但可明显增加载流子迁移率,从而有效降低了薄膜的方块电阻.在两个相同的薄膜硅/单晶硅太阳能电池上分别沉积(222)和(400)ITO优先取向膜,光电转换效率分别为10.3%和12.9%,表明(400)取向更有利于提高电池效率.经优化,最佳衬底温度(Ts)为225℃,最佳氧流量(fO2)为4sccm.在优化的沉积条件下制备ITO薄膜,其电阻率可达到4.8×10-4Ω·cm,可见波段的透过率大于90%,性能指数为3.8×10-2□/Ω.     

掺Sn的In2O3透明导电膜生长优先取向对其光电性能的影响

采用反应热蒸发法制备掺Sn的In2O3(ITO)透明导电膜,系统研究了ITO薄膜生长的优先取向对其光电性能的影响.结果表明,ITO薄膜(400)取向的优先生长对其透过率影响很小,但可明显增加载流子迁移率,从而有效降低了薄膜的方块电阻.在两个相同的薄膜硅/单晶硅太阳能电池上分别沉积(222)和(400)ITO优先取向膜,光电转换效率分别为10.3%和12.9%,表明(400)取向更有利于提高电池效率.经优化,最佳衬底温度(Ts)为225℃,最佳氧流量(fO2)为4sccm.在优化的沉积条件下制备ITO薄膜,其电阻率可达到4.8×10-4Ω·cm,可见波段的透过率大于90%,性能指数为3.8×10-2□/Ω.     

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