无接触法测量多晶硅材料的少子扩散长度

用微波光电导谱仪无接触、非破坏性地测量了多晶硅的微波光电导谱,推导了由光电导谱计算多晶硅样品的少子扩散长度和表面复合速度的计算方法,并由此算得了样品的少子扩散长度和表面复合速度。测试区域是一个直径为3mm的圆斑。这是一种简便而又准确的测试方法。这样的方法还适用于GaAs薄片材料少子扩散长度的测量和计算。     

用微波光电导谱仪测量p—n结少子扩散长度

用微波光电导谱仪测量了一些pn结样品的微波光电导谱(MPCS),对于每一块样品光分别从p面和n面入射,因而可以测得不同的谱;讨论了从pn结的MPCS中计算p区、n区少子扩散长度的方法,并用计算机拟合得到这些样品的p区、n区少子扩散长度和表面复合速度等参数;由于是无接触测试,因此本方法可作为某些pn结器件制造工艺过程中寻找最佳工艺条件的一种监测手段。     

GaAs、Al_xGa_（1－x）As外延层少子扩散长度及霍耳迁移率的无接触测

用微波介质波导法无接触测试了生长在半绝缘衬底上的ＧａＡｓ、ＡｌｘＧａ１－ｘＡｓ外延层的微波光电导谱和横向磁阻，给出了从微波光电导谱计算少子扩散长度和从横向磁阻计算霍耳迁移率的方法，并且由此算得外延层的少于扩散长度和霍耳迁移率．本方法对被测样品的几何形状和尺寸无特殊要求，测试区域小于５×５ｍｍ２，具有无损伤、不污染的优点，并配有微机控制，测试迅速方便．     

GaAs,AlxGa1—xAs外延层少子扩散长度及霍耳迁移率的无接触测试

用微波介质波导法无接触测试了生长在半绝缘衬底上的ＧａＡｓ、ＡｌｘＧａ１－ｘＡｓ外延层的微波光是导谱和横向磁阻，给出了从微波光电导谱计算了少子扩散长度和从横向磁阻计算霍耳迁移率的方法，并且由此算得外延层的少子扩散长度和霍耳迁移度，本方法对波测样品的几何形状和尺寸无特殊要求，测试区域小于５×５ｍｍ＾２，具有无损伤，不污染的优点，并配有微机控制，测试迅速方便。     

有相异表面复合速度时半导体薄片少子连续方程的解及应用

本文给出了有相异表面复合速度时半导体薄片少子连续方程的一种新解法。数值计算结果表明,薄片的少子光电导衰退曲线可以用这种解的一次模和二次模之和来表示。可以使用这些结果讨论一些薄片的少子寿命和表面复合速度。     

微波反射光电导衰退技术在InGaAs台面结器件工艺中的应用

微波反射光电导衰退法是一种非接触式的半导体材料少子寿命表征手段,本文用微波反射光电导衰减法测试了台面InGaAs光电器件制备中各单项工艺(刻蚀、腐蚀、硫化)中InCaAs样品的少子寿命分布,结果表明,离子刻蚀使得样品少子寿命降低,非均匀性增大,而湿法腐蚀能够在一定程度上修复离子刻蚀带来的损伤,损伤区域中心的少子寿命增大,寿命分布也更加均匀,硫化钝化能够进一步提高损伤区域少子的寿命,却使寿命分布均匀性变差.可见,微波反射光电导衰减法可以简单无损地得到样品少子寿命分布,对工艺改进具有重要的指导意义.     

微波反射光电导衰退技术在InGaAs台面结器件工艺中的应用

微波反射光电导衰退法是一种非接触式的半导体材料少子寿命表征手段，本文用微波反射光电导衰减法测试了台面InGaAs光电器件制备中各单项工艺(刻蚀、腐蚀、硫化)中InCaAs样品的少子寿命分布，结果表明，离子刻蚀使得样品少子寿命降低，非均匀性增大，而湿法腐蚀能够在一定程度上修复离子刻蚀带来的损伤，损伤区域中心的少子寿命增大，寿命分布也更加均匀，硫化钝化能够进一步提高损伤区域少子的寿命，却使寿命分布均匀性变差。可见，微波反射光电导衰减法可以简单无损地得到样品少子寿命分布，对工艺改进具有重要的指导意义。     

量值恒定的表面光电压法测量半导体少子扩散长度的研究

为了在保持材料完整性的基础上,对单晶硅材料的质量进行评价,设计了一种利用表面光电压测量半导体少子扩散长度的系统.系统采用斩波器、单色仪和锁相放大器来获取半导体表面光电压信息,利用表面光电压与材料的光吸收系数的关系得出半导体少子扩散长度,重点阐述了系统的测量原理及各个模块的设计与实现方法.检测结果表明,量值恒定的表面光电压法用于测量半导体少子扩散长度能达到预期的效果.     

微波反射光电导衰退技术在InGaAs台面结器件工艺中的应用

微波反射光电导衰退法是一种非接触式的半导体材料少子寿命表征手段，本文用微波反射光电导衰减法测试了台面InGaAs光电器件制备中各单项工艺（刻蚀、腐蚀、硫化）中InCaAs样品的少子寿命分布，结果表明，离子刻蚀使得样品少子寿命降低，非均匀性增大，而湿法腐蚀能够在一定程度上修复离子刻蚀带来的损伤，损伤区域中心的少子寿命增大，寿命分布也更加均匀，硫化钝化能够进一步提高损伤区域少子的寿命，却使寿命分布均匀性变差。可见，微波反射光电导衰减法可以简单无损地得到样品少子寿命分布，对工艺改进具有重要的指导意义。     

样品厚度对表面光电压法测试少子扩散长度的影响

本文定量分析了样品厚度d及单色光的透入深度α~(-1)对表面光电压法测试少于扩散长度的影响,并从实验上进行了验证.本文还讨论了样品厚度对两点法直读少子扩散长度测试结果的影响,并给出从测得的表观扩散长度定出真实扩散长度的方法.观察了光生非平衡载流子的注入水平对扩散长度测试结果的影响.     

用半导体中微波光吸收谱研究表面复合速度和扩散浓度(英文)

This paper presents a new method of analysis and measurement. When a semiconductor wafer is illuminated by microwave and light, the microwave transmission coefficient(MTC) through a sample is related to the wavelength of light. When the wavelength of light is continuously changed, the MTC is changed simultaneously. We have theoretically analyzed the relationship among the MTC and the diffusion length, and the lifetime of minority carrier and the surface recombination velocity. All these parameters can be determined by the microwave and light absorption spectroscopy. We made an instrument to measure the MTC at various light wavelengths. This is a contactless measuring method, with a measuring area being circular spot about 7mm2. The sample can be removed freely on the testboard. There is a calculating result with a minimal standard deviation by using a program of nonlinear curve fitting.     

Coupled-mode analysis of an electrooptic frequency shifter

In this paper, we present a semiclassical wave equation analysis using a coupled-mode expansion formalism to study the effect of a microwave field on a train of short optical pulses co-propagating in a traveling-wave modulator structure. This device can continuously shift the central frequency of light pulses. We demonstrate the effect of the applied field on the light spectrum, the dependence on the relation between microwave wavelength and pulse length, and the effect of changing the interaction length or the power of the applied microwave field. The results of the calculation of these effects are presented.     

激光辐射多功能集成防护镜

为了减少和避免激光和微波辐射眼损伤,设计研制了防激光、防微波、激光探测告警为一体的多功能防护镜。该防护镜由特定功能的光学部件和光电子模块组成,包括多功能复合防护镜片、镜架和激光探测报警系统。进行了多功能防护镜复合技术研究和防护性能测试。结果表明,该防护镜在激光波长532nm,1064nm,790nm,840nm的光密度为4.0～7.28;可见光积分透过率为18.7%;微波衰减大于20dB;报警系统在532nm,1064nm和840nm激光波长能提供自动检测和声光报警,报警器的探测灵敏度为10-7/cm2;该防护镜可承受1g质量、300m/s～400m/s速率的钢制球形破片的冲击;防护镜总质量小于200g,该防护镜防护波段宽、对激光和微波的衰减倍率高、防护角大、可见波段透光性好、可分体和组合使用、体积小、重量轻、便于佩戴、适用于个人佩戴防护和光电传感器的防护。在现代光学实验和各种激光与微波作业环境,以及反恐和公共安全中是不可缺少的防护器材。     

基于光纤环的可调谐微波光子滤波器

设计了2种基于光纤环和啁啾光栅（CFBGs）的无源可调谐微波光子滤波器的新颖结构。这两种结构的滤波器可通过改变输入光波长来实现滤波器自由频程（FSR）的调谐,其所需的FSR可通过光纤环中CFBs的写入位置来控制。研究结果表明,2种滤波器的结构是有效和可行的,在微波和毫米波光纤系统中有着潜在的应用价值。     

Design and simulation of micromechanical thermal converter for RF power sensor microsystem

This paper discusses the thermo-mechanical simulations performed with the aim to optimize the temperature distribution of the microwave power sensor (MPS) microsystem keeping the thermal stress as low as possible. The concept of the absorbed power measurement is based on a thermal conversion, where the dissipated or absorbed RF power is converted into the thermal power, inside a thermally isolated system, so-called the micromechanical thermal converter (MTC) device. A new MTC approach uses a GaAs with an active high electron mobility transistor (HEMT) heater. New technology of low stress polyimide has been used for MTC thermal isolation.By means of thermo-mechanical simulations, we propose a GaAs micromechanical thermal converter design and a layout of the active sensor elements (HEMT heater and a temperature sensor TS) placed on the MTC structure. Spatial temperature distribution, thermal time constant, thermal stress and displacement and the power to temperature characteristics are calculated from the heat distribution. These findings are compared with results of thermo-mechanical measurement of real micromachined MTC devices. The 3-D thermal and thermo-mechanical simulations were performed, using the CoventorWare simulator.     

适于蜂窝网的高效机器类通信业务调度机制

Cellular-based Machine-Type Communication (MTC) will become more and more important in the near future for the advantage of the long-distance wireless communication. However, a large number of MTC applications introduce heavy load to cellular network. MTC traffic scheduling schemes are proposed to avoid congestion in this paper. Our approaches are based on the delay-tolerance of MTC traffic. Some MTC traffic is postponed until the network load becomes light. Moreover, our scheme efficiently utilizes the bandwidth resources reserved for handover in traditional cellular network. Simulation results show that the utility usage of radio resources is improved and the congestion probability is reduced.     

可调谐微波光子带通滤波器的理论分析

提出一种基于啁啾光纤光栅（CFBG）的可调谐级联结构的微波光子滤波器。通过原理分析表明,这种滤波器在一定的宽频带范围内能通过调整光载波波长来实现调谐通带。仿真分析了滤波器的频率响应受光谱宽度的影响。结果表明这种可调谐滤波器级联结构是可行的。     

Lumped 50-Ω Arrays of SNS Josephson Junctions

For the first time, lumped series arrays of Josephson junctions have been fabricated with a transmission line-matched 50-Omega resistance. These arrays also have the thousands of junctions necessary to produce a metrologically significant voltage. This approach is expected to increase the output voltage per array and to optimize their performance for Josephson voltage standards. Traditional Josephson arrays for voltage standards have used distributed microwave structures, where array lengths are several multiples of the driving wavelength. The lumped arrays in this work have physical lengths shorter than a quarter of the microwave drive wavelength and total normal-state resistances nearly equal to the transmission line impedance. Fabrication of these arrays was made possible by use of a newly developed Nb-(MoSi₂-Nb)_n stacked junction technology. We present measurements of the microwave response of lumped arrays with total normal resistances up to 54 Omega and with various termination resistances. A simple numerical model is presented that accounts for the spatial distribution of the microwave current and for the nonuniformity of the junction critical currents. The resulting simulations agree well with experimental results     

Effect of the Copper Content on the Kinetics of the Microwave Photoconductivity of CIGS Solid Solutions

Semiconductors - The kinetics of the photoresponse of microwave photoconductivity (9 GHz, TE101-type cavity) on excitation by laser light pulses with a wavelength of 337 nm and a duration of 8 ns...     

Optical fiber Fabry-Perot cavities and recirculating delay lines astunable microwave filters

The radio frequency or microwave responses of single-mode fiber Fabry-Perot cavities and recirculating delay lines are studied. It is shown that fiber Fabry-Perot cavities may be used as bandpass filters and the recirculating delay lines as bandstop filters at radio or microwave frequencies. These electric filters are tunable by electrooptic effects since the bandpass or bandstop characteristic changes when the cavity or the delay line length is varied by a few tenths of an optical wavelength. The ultimate limit on speed of tuning is set by the coherence time of the light source. The dependence of the filter responses on the spectral purity of light is studied. Examples are given to illustrate the tunability of these electric filters. The availability of various components required to build the tunable RF or microwave filters is reviewed