用于太赫兹成像的CMOS肖特基二极管三维结构研究（英文）

提出了一种简单、科学、有效的高截止频率肖特基势垒二极管设计方法。通过SMIC 180 nm工艺制备的肖特基二极管的截止频率为800 GHz,分析测试结果和仿真数据优化后的肖特基势垒二极管截止频率可以达到1THz左右。完成了包括天线、匹配电路和肖特基势垒二极管的集成探测器,在220 GHz下其测试响应率可达130 V/W,等效噪声功率估计为400 pW/Hz~(1/2)。完成了陶瓷瓶内不可见液面的成像实验并取得了良好的效果。     

截止频率8.7 THz的平面肖特基势垒二极管

肖特基势垒二极管(SBD)具有强非线性效应、速度快及容易系统集成等特点,常用于微波、毫米波及太赫兹波的产生和检测。本文通过电子束光刻等技术制作出肖特基接触直径1 μm的二极管,并对二极管进行了直流测试和射频测试。经过直流测试,二极管的串联电阻为10.2 Ω,零偏结电容为1.76 fF,肖特基结截止频率达到了8.7 THz;相同管子的射频测试串联电阻为15.4 Ω,零偏结电容1.46 fF,肖特基结截止频率也达到了7 THz。     

低电阻GaN基太赫兹空气桥结构平面肖特基二极管

提出了通过增大欧姆接触电极包围角提高GaN基太赫兹肖特基二极管的截止频率的方法,该方法减小了空气桥结构平面肖特基二极管的串联电阻,进而提高了器件的截止频率.设计并制备了不同欧姆接触电极包围角的空气桥结构平面肖特基二极管,通过对器件Ⅰ-Ⅴ特性及C-V特性的测量,可知随着欧姆接触电极包围角的增大,肖特基二极管的串联电阻减小,而肖特基二极管的总电容并没有受影响.欧姆接触电极全包围结构的肖特基二极管截止频率为264 GHz,约为欧姆接触电极包围角为180°器件的1.6倍.     

用于太赫兹探测的InP基异维肖特基二极管

异维肖特基二极管(HDSD)是一种具有三维金属-二维半导体结的特殊的肖特基势垒二极管。由于具有较小的结电容和串联电阻,HDSD在太赫兹探测中很有应用潜力。本文研制了InP基HDSD,据我们所知相关工作尚未被报道过。与GaAs基HDSD相比,可以预期InP基HDSD有着更好的性能,一方面因为更高的电子迁移率和二维电子气(2DEG)浓度,另一方面因为更小的肖特基势垒高度。通过交流测量得到的截止频率高于500GHz,表明InP基HDSD具有应用于太赫兹探测的潜力。     

GaAs肖特基二极管外差接收系统用于托卡马克电子回旋辐射的诊断

本文给出了采用GaAs肖特基势垒二极管外差接收系统诊断CT-6托卡马克二次谐波非寻常模电子回旋辐射的实验结果。GaAs肖特基势垒二极管外差接收系统的工作频率为64～72GHz,其最小可探测功率小于10~(-10)W(中放带宽为500MHz),用于CT-6托卡马克电子回旋辐射的诊断具有足够的探测灵敏度、空间分辨率和时间分辨率。     

W 波段宽带高灵敏度功率检波器

在对肖特基二极管等效电路模型精确建模的基础上,设计并制作了W 波段宽带高灵敏度功率检波器。根据GaAs 低势垒肖特基二极管的物理结构,建立了二极管等效电路模型,并通过对W 波段检波器试验模块的研制和测试提取了准确的电路模型参数。最后,针对宽带工作要求,根据二极管等效电路模型,优化了射频阻抗匹配网络,使检波器工作频率能够覆盖78～98 GHz。测试结果表明,当输入功率为-30 dBm 时,82 GHz 处检波灵敏度达到了7000 mV/ mW,78～98 GHz 范围内检波灵敏度高于1500 mV/ mW,实测正切灵敏度优于-36 dBm。实测和仿真结果一致,验证了二极管等效电路模型的准确性。     

高截止频率肖特基二极管仿真模型研究

基于表面沟道型平面肖特基势垒二极管基本结构,采用GaAs 0.15μm伪高电子迁移率晶体管（pseudomorphic high electron mobility transistors, pHEMT）工艺制程,提出了一种垂直沟道长跨度空气桥的肖特基二极管模型.研究了不同阳极直径对肖特基二极管级联电阻的影响,对比分析了不同焊盘间距下肖特基二极管模型的S参数仿真结果,得到最优空气桥长度;仿真了最优焊盘间距下二极管肖特基结的TCAD模型,根据仿真得到的特性曲线提取肖特基二极管的SPICE参数.经实验测试,该二极管具有极低的零偏置结电容,截止频率高达9 THz,仿真结果与实测结果吻合度较高,可用于太赫兹频段上.     

金属/有机高分子膜/n-InP肖特基势垒

本文介绍用有机高分子膜(LB膜和聚酰亚胺)代替n型InP肖特基势垒二极管中的薄氧化层,所得到的肖特基势垒二极管的势垒高度大于0.7eV,反向漏电流小于2.3×10~(-5)A/cm~2,性能稳定.还叙述了有机高分子膜的制备方法,电学测量结果,并与金属/薄氧化膜/n-InP肖特基势垒进行了比较,同时讨论了该法的优缺点.     

基于肖特基二极管的670 GHz四次谐波混频器设计

常温固态太赫兹谐波混频器是太赫兹系统应用中的关键器件。介绍了一款基于肖特基二极管的670 GHz四次谐波混频器的仿真与设计。在高频结构仿真软件(HFSS)中对准垂直结构肖特基势垒变阻二极管进行三维结构建模,采用基于谐波平衡算法的整体综合仿真方法对混频器进行仿真和优化。结果表明：在功率为10 mW的167 GHz本振信号驱动下,混频器单边带变频损耗在637~697 GHz射频频率范围内小于13.8 dB,3 dB变频损耗带宽为60 GHz;最优单边带变频损耗在679 GHz为10.6 dB。     

220GHz 平衡式二倍频器设计

本文介绍一种基于平面肖特基势垒二极管的220GHz 平衡式二倍频器设计。通过输入、输出信号的电磁场模式 变化实现平衡结构,并控制偏置电压和输入功率使二极管工作于变容模式。采用HFSS 和ADS 联合仿真获得最佳二极管 嵌入电路,输入功率为50mW 时得到最佳变频效率为21%,在212GHz 至235GHz 范围内变频损耗优于8dB。     

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.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.