高可靠性、高基频及小延时晶体滤波器

研究了一种高可靠性,高基频及小延时晶体滤波器的设计方法。采用减少晶体元件和在滤波器的幅频曲线上引入衰耗峰的方法,同时实现了滤波器的小延时和小矩形系数等指标。为了保证滤波器的高可靠性,采用离子刻蚀工艺加工了高基频晶体谐振器,并对磁芯采用充磁处理,实现了滤波器的全密封结构。该滤波器的工作频率为70 MHz,3dB带宽为151.4kHz,带内波动小于0.5dB,通带内(69.95~70.05 MHz)的群延时波动小于3μs,矩形系数小于2.8。     

低幅相畸变SAW滤波器技术研究

介绍了一种用于相控阵雷达的高相位一致性声表面波(SAW)滤波器,该种滤波器采用谐振型5换能器结构,基片材料为42°Y-X切型LiTaO3。通过对结构优化,提高了矩形系数,改善了群延时波动。制作出一款频率为500MHz,插入损耗1.2dB的滤波器,并该设计满足了相控阵雷达对声表面波滤波器高幅相一致性的要求,生产成品率提高。     

文摘选辑

(一)声表面波技术051 采用一步制作工艺的低损耗SAW器件——Lewis,M:《1983 Ultras.Symp Proc.》104—108本文叙述单相单向换能器的研制.这种设计用“抽样”换能器使换能器内没有反射器组.制作这样的器件只需要一步光刻即可.原型LiNbO~3器件具有极佳的通带性能,其插入损耗小于3dB.     

线形宽带超声相控阵换能器的声场分析

讨论了一种计算矩形活塞阵元声场脉冲响应函数的简便算法,通过对不同延时量的矩形活塞阵元声场脉冲响应函数进行叠加,得到线形换能器阵列的脉冲响应函数;再施以宽带脉冲激励函数,得到线形换能器阵列的声场分布。比较了3种不同换能器的脉冲响应及声场分布,该法对工业无损检测领域超声成像用换能器参数优化具有重要意义。     

针对级联型ⅡR滤波器群延时的均衡优化技术

为了减小由非恒定群延时所引起的滤波器的输出信号失真,本文提出一种适用于级联型无限长脉冲响应数字滤波器的群延时均衡优化方法.通过在级联型ⅡR数字滤波器每一级的输出插入全通均衡器,减小群延时在通带范围内的变化,进而减小滤波器的输出信号失真.对于本文提出的群延时优化方法,当采用1阶和2阶均衡器进行电路优化时,在0~100Hz的通带范围内,分别将群延时的变化量减小了28.19%和49.93%.基于0.18μm CMOS标准单元库进行逻辑综合与版图设计,最终得到整个滤波电路IP核版图的面积为0.1747mm².相比于已有文献方法,本文方法在群延时优化上效果显著,电路实现上功耗和面积较小,非常适合片上系统应用.     

兼顾群延时与宽带匹配的SiGe HBT LNA设计

选用SiGe HBT作为电路的有源器件,利用基极串联电感LB与反馈支路、晶体管Miller效应所产生的寄生电容形成的T型匹配网络取得了输入阻抗的良好匹配,并就基极串联电感值对系统群延时的影响进行了讨论,优化LB以满足兼容群延时与宽带匹配的要求.该放大器在3.1～10.6 GHz的带宽内增益达到12.7 dB,增益变化小于等于1.8 dB,噪声小于3.85 dB,群延时小于24 ps,静态功耗仅为6.3 mW.     

横向耦合谐振滤波器寄生模式抑制的研究

该文应用耦合模理论,重点研究了几个关键因素对横向耦合谐振滤波器高次模式对应旁瓣相对于主通带相对衰减量的影响.这几个关键因素包括相对膜厚、反射栅与换能器周期比、换能器间汇流条宽度等.研究表明,该文在设计频率为159.2 MHz的横向耦合谐振滤波器时,对高次模式引起的旁瓣作了抑制处理,该文给出了此滤波器的计算模拟结果和实验测试数据.实验器件匹配后具有高阻带抑制(通带外抑制达50 dB)、低插损(2.9 dB)和平坦的通带(通带波纹小于0.3 dB),1 dB带宽为130 kHz.     

电视机电路CAD中声表面波滤波器的黑盒模型

本文根据四端网络Y参数的理论建立了电视机图象中放声表面波滤波器的计算机黑盒模型。指出器件的等效四端网络中的Y_(21)应是端接阻抗的参变数,从而建立了修正公式。利用此模型可以计算整个中放电路系统的频率特性,并具有较高的精度,通带内幅频特性误差小于1dB,群延时误差约为20ns,进一步可用于对电路元件及SAW滤带器的参数作优化设计。     

基于序列锥规划方法的群延时约束等纹波有限冲激响应数字滤波器优化设计

有限冲激响应数字滤波器(FIR)的优化设计理论,一般是使设计的FIR滤波器频率响应与期望滤波器频率响应之间的误差最小并通过优化技术进行求解.但是已有的这些方法大都关注于通带和阻带内的幅频特性,而对于非线性群延时约束考虑较少,因此对于群延时要求较高的应用场合,这些方法是不适用的.该文提出了一种群延时约束的等纹波有限冲激响应数字滤波器设计新方法,该方法主要思想是采用泰勒级数近似将带有非线性群延时约束条件的原等纹波滤波器优化设计问题在好的初始迭代点附近转化为序列二阶锥规划子问题进行求解,较好的解决了对群延时要求较高的问题.仿真结果表明,该方法可以有效的减小滤波器群延时误差,最小化通带和阻带纹波,提高了滤波器的优化设计性能.     

60MHz高带外抑制,小型化SAW滤波器的研制

文章应用叉指对数少,带外抑制高,并可以修正通带倾斜的高斯组合函数,同海明函数抽指加权综合设计,在Y127.96°切X传播LiNbo_3基片上研制成功了∫_0=60MHz,B_(LdB)=2.5MHz,带外抑制大于40dB,高端48dB,插损小于13dB,矩形系数K(B_(-40)/B_(-3))=2.15,通带波动小于0.8dB,封装在TO-8外壳中的高性能SAW滤波器,满足了某通信机的使用要求。这种较理想的加权设计方式选择,达到了较满意的器件性能同较小体积的统一。应用于具有良好矩形系数,出现较严重通带倾斜的较窄带和窄带SAW滤波器的设计最为适合。在加权设计方式优选中,同凯塞尔窗截断辛格函数加权和可以修正通带倾斜的瓦塞尔函数加权,进行了理论计算以及试验结果分析对比。对具体设计作了较详细阐述。尤其对较复杂的抽指加权IDT设计程序作了简化,使CAD程序运算快、精确、实用。     

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.     

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.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and sub-pixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

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.     

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.