大功率SiC MESFET内匹配技术及测试电路研究

采用管壳内匹配及外电路匹配相结合的方法,成功制作四胞合成大功率高增益SiC MESFET.优化了芯片装配形式,采用内匹配技术提高了器件输入、输出阻抗.优化了测试电路结构,成功消除了输入信号对栅极偏置电压的影响,提高了电路稳定性.四胞器件在脉宽为300 μs、占空比为10%脉冲测试时,2 GHz Vds=50 V脉冲输出功率为129 W(51.1 dBm),线性增益为13.0 dB,功率附加效率为31.4%.     

2～8GHz宽带GaN功率放大器MMIC

基于0.25μm Ga N HEMT工艺,研制了一款两级拓扑放大结构的2~8 GHz宽带功率放大器MMIC(单片微波集成电路)。MMIC所用Ga N HEMT器件结构经过优化,提高了放大器的可靠性和性能;电路采用多极点电抗匹配网络,扩展了放大器的带宽,减小了电路的损耗。测试结果表明,在2~8 GHz测试频带内,在脉冲偏压28 V(脉宽1 ms,占空比30%)时,峰值输出功率大于30 W,功率附加效率大于25%,小信号增益大于24 d B,输入电压驻波比在2.8以下,在6 GHz处的峰值输出功率达到50 W,功率附加效率达到40%;在稳态偏压28 V时,连续波饱和输出功率大于20 W,功率附加效率大于20%。尺寸为4.0 mm×5.0 mm。     

2.14GHz GaN-HEMT脉冲功率放大器设计(英文)

设计了一款用于无线通信W-CDMA,工作在2.04~2.24GHz的脉冲功率放大器。采用微波仿真软件ADS对放大器的输入/输出阻抗匹配电路、偏置电路及其整体功放电路进行了仿真和优化。测试结果表明,在2.14GHz处的三阶交调值为32.14dBc,小信号增益为18dB,饱和输出功率为44dBm,功率附加效率达到55%。在2.04~2.14GHz频率范围的增益平坦度小于1dB。测试结果和仿真结果相近。     

Ku波段宽带氮化镓功率放大器MMIC

基于0.25μm栅长GaN HEMT工艺,采用三级放大拓扑结构设计了一款Ku波段GaN功率放大器.放大器设计从建立大信号模型出发,输出匹配网络和级间匹配网络均采用电抗匹配减小电路的损耗,从而提高整体放大器的功率效率.测试结果表明,该放大器在14.6~18GHz频带内,小信号增益30dB,脉冲饱和输出功率达15W,功率附加效率(PAE)大于32%;在14.8GHz频点处,放大器的峰值功率达19.5W,PAE达39%.该结果表明GaN MMIC具有高频高功率高效率的优势,具有广阔的应用前景.     

一种预失真可调InGaP/GaAs HBT射频功率放大器

提出了一种具有可调预失真功能的共集电极放大电路,对其动态偏置点及双负反馈回路进行了分析.AWR Microwave Office仿真表明:该预失真电路产生的增益扩展与负相位偏差可以补偿该功率放大器后级电路产生的增益压缩和正相位偏差,提高其线性度.采用该预失真电路作为输入级,设计了一款功率放大器,并基于截止频率为29.5 GHz的2 μm InGaP/GaAs HBT工艺成功流片.测试结果表明,该宽带放大器在3.5 V偏置电压下和1.3～2.0 GHz频段范围内功率增益可达27 dB,P1dB为28.6 dBm,最大功率附加效率为39%.     

6～18 GHz宽带GaN功率放大器MMIC

报道了一款采用三级拓扑结构的6～18 GHz宽带单片微波功率放大器芯片.放大器采用了微带结构,并使用电抗匹配进行设计,减小输出匹配电路的损耗和提高效率.经匹配优化后放大器在6～18 GHz整个频带内脉冲输出功率大于6 W,小信号增益达到25 dB,在14 GHz频点处峰值输出功率达到10 w,对应的功率附加效率为21%...     

一种0.13 μm CMOS K波段宽带功率放大器

基于0.13 μm CMOS工艺,采用多频点叠加的方式,设计了一种K波段宽带功率放大器。输入级采用晶体管源极感性退化方式,实现了宽带输入匹配。驱动级采用自偏置共源共栅放大器,为电路提供了较高的增益。输出级采用共源极放大器,保证电路具有较高的输出功率。后仿真结果表明,在26 GHz处,该功率放大器的增益为22 dB,－3 dB带宽覆盖范围为22.5~30.5 GHz,输出功率1 dB压缩点为8.51 dBm,饱和输出功率为11.6 dBm,峰值附加功率效率为18.7%。     

2～4GHz MMIC低噪声放大器

采用中国电子科技集团公司第十三研究所的GaAs PHEMT低噪声工艺,设计了一款2~4 GHz微波单片集成电路低噪声放大器(MMIC LNA)。该低噪声放大器采用两级级联的电路结构,第一级折中考虑了低噪声放大器的最佳噪声和最大增益,采用源极串联负反馈和输入匹配电路,实现噪声匹配和输入匹配。第二级采用串联、并联负反馈,提高电路的增益平坦度和稳定性。每一级采用自偏电路设计,实现单电源供电。MMIC芯片测试结果为:工作频率为2~4 GHz,噪声系数小于1.0 dB,增益大于27.5 dB,1 dB压缩点输出功率大于18 dBm,输入、输出回波损耗小于-10 dB,芯片面积为2.2 mm×1.2 mm。     

Ku波段内匹配高功率且PAE超过30%的GaN HEMTs放大器

本文报道了一款工作于Ku波段的高功率高效率的内匹配功率放大器。该放大器采用外延于6H-SiC衬底上的栅长为0.3um、栅宽为4mm的 AlGaN/GaN 高电子迁移率晶体管制作而成。为了改善电路的带宽,在输入输出匹配电路中分别采用了T型 预匹配网络。通过使用三维电磁仿真工具优化无源匹配网络,该放大器在Vds=30V、Vgs=-4V,占空比为10%的脉冲偏置下,获得了在13.8~14.3GHz的频率范围内最大输出功率为42.5dBm、功率附加效率为30%~36.4%以及线性增益为7~9.3dB的性能。以这样的功率和效率而言,该放大器功率密度达到4.45W/mm。     

1.8 GHz Doherty功率放大器小型化技术研究

基于In GaP/GaAs HBT工艺设计了一款工作在1. 8 GHz的三级Doherty功率放大器,第一、二级为驱动级,第三级为Doherty放大器。通过分析Doherty结构,在原有基础上重新设计Doherty电路,使用LC元件替代微带线,减小功率分配网络与合路匹配网络的面积,进而缩小整体电路的面积。将输入、输出匹配网络及功分、合路部分集成至基板上,整体封装尺寸5 mm×5 mm。测试结果表明,芯片输入、输出回波损耗优于-15 d B,放大器整体增益优于33 d B,3 d B压缩点输出功率35 d Bm,其中第三级Doherty放大器峰值功率附加效率(PAE) 47. 9%,8 d B回退点的功率附加效率32. 7%。     

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.     

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 subpixel 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。     

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.