S波段大功率、高效率GaN HEMT器件研究

基于国产的SiC衬底GaN外延材料,研制出大栅宽GaN HEMT单胞管芯。通过使用源牵引和负载牵引技术仿真出所设计模型器件的输入输出阻抗,推导出本器件所用管芯的输入输出阻抗。使用多节λ/4阻抗变换线设计了宽带Wilkinson功率分配/合成器,对原理图进行仿真,优化匹配网络的S参数,对生成版图进行电磁场仿真,通过LC T型网络提升管芯输入输出阻抗。采用内匹配技术,成功研制出铜-钼-铜结构热沉封装的四胞内匹配GaN HEMT。在频率为2.7～3.5 GHz、脉宽为3 ms、占空比为50%、栅源电压Vgs为-3 V和漏源电压Vds为28 V下测试器件,得到最大输出功率Pout大于100 W(50 dBm),PAE大于47%,功率增益大于13 dB。     

1～4GHz 80W GaN超宽带功率放大器

基于南京电子器件研究所0.25μmGaN HEMT工艺平台,设计了一款工作频率为1~4GHz,连续波输出功率大于80W的超宽带功率放大器.放大器采用低通L-C匹配网络实现管芯输入输出阻抗到实阻抗的变换;并利用切比雪夫变换器结构实现超宽带匹配;以单路输入输出端口匹配到100Ω后,两路直接电路合成到50Ω的方法实现了大功率超宽带功放的功率合成.放大器偏置电压32V,静态电流0.4A.测试结果显示,在1~4GHz带宽内,放大器连续波输出功率大于49.05dBm （80.3W）,最高输出功率为50.6dBm （114.8W）,饱和功率增益大于9dB,功率平坦度小于±0.8dB,最大漏极效率为62.5%.     

S波段150W GaN内匹配功率放大器

介绍了一种S波段150W GaN内匹配功率放大器。器件采用0.25μm工艺GaN HEMT管芯,内匹配技术对单胞放大器进行输入输出匹配,然后用Wilkinson功率分配器对四路单胞功率放大器进行功率合成。放大器频带范围2.7~3.5GHz。工作电压28V,占空比10%,脉宽0.1ms。单胞放大器输入功率37dBm,输出功率46.5dBm以上,功率附加效率大于50%;合成放大器输入功率43dBm,输出功率51.8dBm(150 W)以上,功率附加效率超过40%。     

X波段60W高效率GaN HEMT功率MMIC

研制了一款采用0.25μm GaN功率MMIC工艺研制的X波段高效率功率放大器芯片。芯片采用三级放大拓扑结构设计。末级匹配电路采用电抗匹配方式兼顾输出功率和效率,同时优化驱动级和末级管芯栅宽比以及级间匹配电路,降低驱动级管芯电流。通过这两种技术途径有效提高芯片的功率附加效率。输入级和级间匹配电路采用有耗匹配方式,扩展工作带宽以及提高稳定性。芯片在8~12GHz频带范围内漏压28V,脉宽100μS,占空比10%工作条件下输出功率达到47.5~48.7dBm,功率增益大于20dB,功率附加效率40%~45%。芯片面积3.5mm×3.8mm,单位面积功率密度为5.57 W/mm2,连续波条件下热阻为1.7K/W。     

L波段GaN自偏压功率放大器

介绍了一款L波段自偏压内匹配功率放大器。器件采用0.25 μm工艺GaN高电子迁移率晶体管(HEMT)管芯，内匹配技术对单胞管芯进行输入输出匹配，放大器的工作频带范围为1.2~1.4 GHz。采用自偏压技术，单电源供电，使电路更为简洁，使用方便。工作电压为28 V，占空比为10%，脉宽为300 μs，在输入功率为26 dBm时，频带内输出功率在40 dBm以上，功率附加效率大于60%，充分显示了GaN功率器件在单电源模块中的性能优势。     

一种平衡式GaN内匹配宽带功率放大器设计

基于南京电子器件研究所的0.5μm GaN HEMT工艺平台,研制了一款2~5 GHz宽带固态功率放大器。采用低通L-C匹配网络消除虚部阻抗,并利用λ/4线实现宽带实阻抗到目标阻抗50Ω的匹配,最后通过3 dB Lange耦合器实现宽带平衡式功率合成设计。测试结果表明,功放在48 V漏电压、1 ms周期、10%射频脉冲时,在2~5GHz频带内,输出功率大于50 dBm(100 W),最高输出功率达到51.2 dBm(132 W),最大功率附加效率52%,合成效率典型值大于85%,二次谐波抑制度大于18 dBc,杂波抑制度大于60 dBc。     

X波段400 W GaN内匹配功率管北大核心CSCD

报道了X波段脉冲输出功率超过400 W的GaN HEMT内匹配功率管。该器件内部包含了4只14.4mm栅宽GaN HEMT管芯。输入输出同时采用了一级L-C阻抗变换和两级微带阻抗变换器。该器件在9.0~10.0GHz频带内,在漏极电压为50V、脉冲宽度100μs、占空比10%测试条件下,输出功率达到了400 W以上,功率增益大于9dB,附加效率高于37.7%,带内峰值输出功率450 W。     

一种高线性宽带功率合成的射频功率放大器北大核心

针对5G通信微基站,提出一种基于GaAs异质结双极晶体管(HBT)工艺,芯片面积为1.3 mm×1.4 mm的高线性宽带宽的射频功率放大器。该放大器采用了异相功率合成方式和J类输出匹配的方法,在两路功率放大器的输入输出端引入了90°相移以及J类模式确定最佳负载阻抗,以此实现高线性宽带宽的特性。在5 V电源和2.85 V偏置电压下,室温条件下测试结果表明,该功率放大器在2~3 GHz频带内,小信号增益为36±0.5 dB。然而在2.4~2.8 GHz频带内,该功率合成结构的功率放大器拥有饱和输出功率大于36 dBm,功率附加效率大于38%。在5G-NR,带宽100 MHz和4G-LTE、带宽20 MHz的调制信号下,在2.4~2.8 GHz工作频带测试,放大器的输出功率为22 dBm,邻近信道功率比(ACPR)约为-43 dBc。     

0.1～2.0 GHz 10W GaN单片行波放大器

报道了一款采用0.25μm GaN功率MMIC工艺研制的0.1~2.0 GHz超宽带功率放大器芯片。芯片采用非均匀分布式拓扑结构进行设计。在管芯栅极端设计稳定结构来提高电路的整体稳定性,在漏极端采用阻抗渐变的方式进行电路匹配,从而提高电路的效率。芯片漏压30 V、连续波条件下,在0.1~2.0 GHz频率范围内,线性增益大于18 d B,功率增益大于13 d B;在0.1~1.5 GHz频率范围内饱和输出功率大于10 W,功率附加效率大于55%,最高效率达到78%。芯片面积2.4 mm×1.9 mm。     

八胞合成X波段140W AlGaN/GaNHEMT的研究与应用

主要研究第三代半导体AlGaN/GaN功率管内匹配问题.采用8个2.5 mm GaN功率芯片设计、合成以及内匹配电路的测试,在漏极电压40 V,脉冲占空比10％,脉宽100μs的条件下进行功率匹配,实现了GaN功率HEMT在X波段8 GHz 140 W功率输出的内匹配电路,并使整个电路的输入、输出电路阻抗提升至50 Ω...     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

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.