检索结果-内蒙古大学图书馆

MRS Online Proceedings Library 1997年第1期482卷 648-659页

作者： S. Cmchibu T. Deguchi T. Sota K. Wada S. Nakamura Materials Department University of California Santa Barbara USA Faculty of Science and Technology Science University of Tokyo Chiba 278 Japan Department of Electrical Electronics and Computer Engineering Waseda University Tokyo 169 Japan Compound Semiconductor Materials Research NTT System Electronics Laboratories Kanagawa Japan Department of Research and Development Nichia Chemical Industries Ltd. Tokushima 774 Japan

Emission mechanisms of the device-quality quantum well (QW) structure and bulk three dimensional (3D) InGaN materials grown on sapphire substrates without any epitaxial lateral overgrown GaN (ELOG) base layers were investigated. The InxGx1−xN layers showed various degree of spatial potential (bandgap) fluctuation, which is probably due to a compositional inhomogeneity or monolayer thickness fluctuation produced by some kinetic driving forces initiated by the threading dislocations (TDs) or growth steps during the growth. The degree of fluctuation changed remarkably around nominal InN molar fraction x=0.2, which changes to nearly 8–10 % for the strained InxGa1−xN. This potential fluctuation induces energy tail states both in QW and 3D InGaN, showing a large Stokes-like shift combined with the red shift due to quantum confined Stark effect (QCSE) induced by the piezoelectric field. The spontaneous emission from undoped InGaN single quantum well (SQW) light-emitting diodes (LED’s), undoped 3D double heterostructure (DH) LED’s, and multiple quantum well (MQW) laser diode (LD) wafers was assigned as being due to the recombination of excitons localized at the potential minima, whose area was determined by cathodoluminescence (CL) mapping to vary from less than 60 nm to 300 nm in lateral size in the case of QW’s. The lasing mechanisms of the cw In0.15Gao.85N MQW LD’s having small potential fluctuation, whose bandgap broadenings are less than about 50 meV, can be described by the well-known electron-hole-plasma (EIHP) picture with Coulomb enhancement. The inhomogenous MQW LD’s are considered to lase by EHP in segmented QW’s or Q-disks. It is desirable to use entire QW planes with small potential inhomogeneity as gain media for higher performance LD operation.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Valence Band Physics in Wurtzite GaN

引用

MRS Online Proceedings Library 1997年第1期468卷 445-456页

作者： T. Azuhata T. Sota S. Chichibu A. Kuramata K. Horino M. Yamaguchi T. Yagi S. Nakamura Department of Electrical Electronics and Computer Engineering Waseda University Tokyo Japan Faculty of Science and Technology Science University of Tokyo Chiba Japan Optical Semiconductor Devices Laboratory Fujitsu Laboratories Ltd. Atsugi Kanagawa Japan Faculty of Engineering Hokkaido University Sapporo Japan Research Institute for Electronic Science Hokkaido University Sapporo Japan Department of Research and Development Nichia Chemical Industries Ltd. Tokushima Japan

We present a summary of recent progress towards the understanding of the valence-band physics in wurtzite GaN. Systematic studies have been performed on the strain dependence of the free exciton resonance energies by photoreflectance measurements using well-characterized samples. Analyzing the experimental data with the Hamiltonian appropriate for the valence bands, the values have been determined of the crystal field splitting, the spin-orbit splitting, the shear deformation potential constants, and the energy gap in the unstrained crystal. Discussions are given on the strain dependence of the energy gaps, of the effective masses, and of the binding energies for the free exciton ground states as well as on the valence band parameters. Using the obtained values and the generalized Elliott formula, the fundamental optical absorption spectra obtained experimentally were analyzed. The values of the elastic stiffness constants, which play a crucial role to determine the shear deformation potential constants, are also given.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Correction To "M-test: A Test Chip For Mems Material Property Measurement Using Electrostatically Actuated Test Structures"

引用

Journal of Microelectromechanical Systems 1997年第3期6卷 286-286页

作者： P.M. Osterberg S.D. Senturia Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA School of Engineering University of Portland Portland OR USA

来源：评论

学校读者我要写书评

暂无评论

A sealed cavity TFR process for RF bandpass filters

A sealed cavity TFR process for RF bandpass filters

引用

1996 International Electron Devices Meeting

作者： Lutsky, JJ Naik, RS Reif, R Sodini, CG MIT Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Cambridge 02139 MA United States

ISBN: (纸本)0780333942

Thin film bulk acoustic wave resonators(TFRs) show considerable promise as a silicon compatible integrated solution for RF bandpass filters with center frequencies in the 1-2 GHz range. This paper presents a VLSI compatible sealed cavity TFR process using reactively sputtered AlN as the piezoelectric film. The devices are free-standing and have a fundamental longitudinal resonance at 1.36 GHz with an insertion loss of 3.5 dB, a K-eff(2) of .4%, and a Q(series) of 210.

关键词： Bandpass filters

来源：评论

学校读者我要写书评

暂无评论

Interaction of soliton with sinusoidal wave packet

引用

IEEE JOURNAL OF QUANTUM ELECTRONICS 1996年第6期32卷 917-924页

作者： Haus, HA Khatri, FI Wong, WS Ippen, EP Tamura, KR Department of Electrical Engineering and Computer Science Research Laboratory of Elecronics Massachusetts Institute of Technology Cambridge MA USA NTT Access Network Service Systems Laboratories Tokai Ibaraki Japan

The interaction of a soliton of the Nonlinear Schrodinger Equation (NSE) with a weak sinusoidal wave packet is treated analytically, The second-order soliton solution containing the original soliton and a perturbing soliton is expanded to first order in the amplitude of the perturbating soliton, From this expansion, one obtains the associate function of Gordon [4] and a continuous change of position and phase of the perturbed soliton, One finds that the soliton experiences a second-order change of velocity under the influence of the perturbation. This result is then used to derive the displacement due to a wave packet of general shape, which is also confirmed by computer simulation.

关键词： Solitons Frequency laboratories Optical fiber cables Acoustic pulses Schrodinger equation Neutron spin echo Shape computer simulation Computational modeling

来源：评论

学校读者我要写书评

暂无评论

Micromachined coplanar waveguides in CMOS technology

引用

IEEE MICROWAVE AND GUIDED WAVE LETTERS 1996年第10期6卷 380-382页

作者： Milanovic, V Gaitan, M Bowen, ED Zaghloul, ME Department of Electrical Engineering and Computer Science George Washington University Washington D.C. DC USA National Institute for Standards and Technology MD USA RF Microsystems Inc. San Diego CA USA

Coplanar waveguides were fabricated in standard complimentary metal-oxide semiconductor (CMOS) with postprocessing micromachining. IC's were designed with commercial CAD tools, fabricated through the MOSIS(1) service, and subsequently suspended by maskless top-side etching, Absence of the lossy silicon substrate after etching results in significantly improved insertion loss characteristics, dispersion characteristics, and phase velocity, Measurements were performed at frequencies from 1 to 40 GHz, before and after micromachining, These show improvement in loss characteristics of orders of magnitude, For the micromachined line, loss does not exceed 4 dB/cm. Before etching, loss as high as 38 dB/cm is measured, Phase velocity nu(p) approximate to 0.8 . c is achieved for the micromachined line.

关键词： CMOS technology Coplanar waveguides Etching Semiconductor waveguides Micromachining MOS devices Design automation Silicon Substrates Insertion loss

来源：评论

学校读者我要写书评

暂无评论

A new algorithm for NMOS AC hot-carrier lifetime prediction based on the dominant degradation asymptote

A new algorithm for NMOS AC hot-carrier lifetime prediction ...

引用

Annual International Symposium on Reliability Physics

作者： S.-W.A. Kim B. Menberu J.E. Chung Department of Electrical Engineering & Computer Science Microsystems Technology Laboratories Massachusetts Institute of Technology Cambridge MA USA

This study presents a new algorithm for improved prediction of AC hot-carrier lifetime. It is based on identifying and projecting the dominant degradation asymptote and accounts for the stress-bias-dependent degradation rate n, and the non-linearity of the degradation time-dependence. Detailed model parameter extraction and lifetime prediction procedures are explained, and applications of the new algorithm demonstrated. Significant differences in the predicted AC-lifetimes are found between the existing and the new algorithms over a wide range of CMOS inverter designs.

关键词： MOS devices Hot carriers Degradation Semiconductor device modeling Prediction algorithms Predictive models Parameter extraction Inverters Algorithm design and analysis computer science

来源：评论

学校读者我要写书评

暂无评论

A sealed cavity TFR process for RF bandpass filters

A sealed cavity TFR process for RF bandpass filters

引用

International Electron Devices Meeting (IEDM)

作者： J.J. Lutsky R.S. Naik R. Reif C.G. Sodini Department of Electrical Engineering and Computer Science M. I. T. MicroSystems Technology Laboratories Cambridge MA USA

Thin film bulk acoustic wave resonators (TFRs) show considerable promise as a silicon compatible integrated solution for RF bandpass filters with center frequencies in the 1-2 GHz range. This paper presents a VLSI compatible sealed cavity TFR process using reactively sputtered AlN as the piezoelectric film. The devices are free-standing and have a fundamental longitudinal resonance at 1.36 GHz with an insertion loss of 3.5 dB, a K/sub eff//sup 2/ of .4 %, and a Q/sub series/ of 210.

关键词： Radio frequency Band pass filters Piezoelectric films Semiconductor thin films Sputtering Acoustic waves Silicon Very large scale integration Resonance Insertion loss

来源：评论

学校读者我要写书评

暂无评论

Intermodulation analysis of FET resistive mixers using Volterra series

Intermodulation analysis of FET resistive mixers using Volte...

引用

Microwave, MTT-S International Symposium

作者： S. Peng P.J. McCleer G.I. Haddad Computer & Communication Research Laboratories Industrial Technology and Research Institute Taiwan Center for High Frequency Microelectronics Solid State Electronics Laboratory Department of Electrical Engineering and Computer Science University of Michigan USA

We have implemented the Volterra-series method to analyze intermodulation (IM) distortion in FET resistive mixers. The nonlinearities of the channel conductance of a NE71000 MESFET and a NE32400 HFET were first characterized using a low-frequency harmonic power measurement. The data was then used in a simulation program and results for two-tone IM distortion in X-band were compared with the measured data for both MESFET and HFET resistive mixer circuits. Very good agreement was achieved in each case. We have also shown by simulation that the two separate contributions to the third-order IM distortion from the mixing between the input signals themselves and the mixing between the input signals and the second-order mixing products have a very strong cancellation, which results in the low IM distortion in the FET resistive mixers observed in measurements.

关键词： FETs Harmonic analysis Intrusion detection HEMTs MODFETs Distortion measurement Frequency MESFETs Power system harmonics Power measurement

来源：评论

学校读者我要写书评

暂无评论

Room-temperature performance of double-fused 1.54 /spl mu/m vertical-cavity laser

Room-temperature performance of double-fused 1.54 /spl mu/m ...

引用

Indium Phosphide and Related Materials Conference

作者： D.I. Babic K. Streubel R.P. Mirin J. Piprek N.M. Margalit J.E. Bower E.L. Hu D.E. Mars L. Yang K. Carey Department of Electrical and Computer Engineering University of California Santa Barbara USA Department of Electronics Royal Institute of Technology Stockholm Sweden Materials Science Program University of Delaware Newark USA Hewlett Packard Laboratories Palo Alto CA USA

The progress in understanding wafer-fused vertical-cavity lasers and improvements in fabrication techniques have led to the realization of the first room-temperature continuous-wave operating 1.54-/spl mu/m vertical-cavity lasers. By demonstrating continuous-wave operation at room temperature using vertical-cavity lasers fabricated by two wafer fusion steps, we have shown that wafer fusion is a viable technique. The lasers comprise strain compensated InGaAsP quantum-well active layers sandwiched between two AlGaAs/GaAs quarter-wave mirrors. Characteristics discussed include cavity losses, the gain-current density relationship, and voltage-current characteristics.

关键词： Vertical cavity surface emitting lasers Mirrors Optical pulse generation Absorption Pulse measurements Quantum well lasers Doping Temperature Propagation losses Size measurement

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：